library(tidyverse)
library(gtsummary)
library(psych)
library(multilevel)
library(performance)
library(sjPlot)
library(patchwork)
library(lavaan)
library(lavaanPlot)
library(semPlot)
library(semTools)
data<- read.csv("C:/Users/msaleeb/Downloads/Redcap Projects other than pregmpox/Self-management/Analysis-self management/Data-raw.csv",
                na.strings = "", stringsAsFactors = T)


manag<- data |> filter(redcap_repeat_instrument=="management_scale")

# To select only the self management questions
manag<- manag[,75:131]

## to remove the questions: specify where
manag <- manag[,-c(8,36)]
# Transform all 999 or 6 to NA (not applicable is considered as missing data)

manag <- manag |>
  mutate(
    across(Q1:Q27, ~ na_if(.x, 999))
  )

manag <- manag |>
  mutate(
    across(Q1:Q27, ~ na_if(.x, 6))
  )


manag <- manag |>
  mutate(
    across(Caregiver.Q1: Caregiver.Q28, ~ na_if(.x, 999))
  )

manag <- manag |>
  mutate(
    across(Caregiver.Q1: Caregiver.Q28, ~ na_if(.x, 6))
  )


## PWE
PWE <- manag |> filter(!is.na(Q1))
PWE <- PWE %>%
  dplyr::select(-Q3, -Q14, -Q20)
# Merge the responses for PWE and caregiver together

# Questions 3, 14, and 20 are removed from PWE because they didn' match anthing in the caregiver questionnaire

# All of the codes that contain # before are not executed


manag$Q1  <- coalesce(manag$Q1, manag$Caregiver.Q1)
manag$Q2  <- coalesce(manag$Q2,  manag$Caregiver.Q2)
#manag$Q3 <- coalesce(manag$Q3,  manag$Caregiver.Q3)
manag$Q4  <- coalesce(manag$Q4,  manag$Caregiver.Q4)
manag$Q5  <- coalesce(manag$Q5,  manag$Caregiver.Q5)
manag$Q6  <- coalesce(manag$Q6,  manag$Caregiver.Q6)
manag$Q7  <- coalesce(manag$Q7,  manag$Caregiver.Q7)
manag$Q8  <- coalesce(manag$Q8,  manag$Caregiver.Q8)
manag$Q9  <- coalesce(manag$Q9,  manag$Caregiver.Q9)
manag$Q10 <- coalesce(manag$Q10, manag$Caregiver.Q10)
manag$Q11 <- coalesce(manag$Q11, manag$Caregiver.Q11)
manag$Q12 <- coalesce(manag$Q12, manag$Caregiver.Q12)
manag$Q13 <- coalesce(manag$Q13, manag$Caregiver.Q13)
#manag$Q14 <- coalesce(manag$Q14, manag$Caregiver.Q14)
manag$Q15 <- coalesce(manag$Q15, manag$Caregiver.Q15)
manag$Q16 <- coalesce(manag$Q16, manag$Caregiver.Q16)
manag$Q17 <- coalesce(manag$Q17, manag$Caregiver.Q17)
manag$Q18 <- coalesce(manag$Q18, manag$Caregiver.Q18)
manag$Q19 <- coalesce(manag$Q19, manag$Caregiver.Q20)
#manag$Q20 <- coalesce(manag$Q20, manag$Caregiver.Q20)
manag$Q21 <- coalesce(manag$Q21, manag$Caregiver.Q21)
manag$Q22 <- coalesce(manag$Q22, manag$Caregiver.Q22)
manag$Q23 <- coalesce(manag$Q23, manag$Caregiver.Q23)
manag$Q24 <- coalesce(manag$Q24, manag$Caregiver.Q24)
manag$Q25 <- coalesce(manag$Q25, manag$Caregiver.Q25)
manag$Q26 <- coalesce(manag$Q26, manag$Caregiver.Q27)
manag$Q27 <- coalesce(manag$Q27, manag$Caregiver.Q28)

1 Descriptive stats for both PWE and caregiver

The Self-management questions: Q1: In the last 6 months, how often did you take your seizure medication the way the nurse or clinical officer prescribed it?

Q2: In the last 6 months, how often did you take seizure medicine at a fixed time linked to a daily routine? For example, after waking or breakfast, when going to sleep, after fetching water, or using any other way to remember.

Q3: In the last 6 months, how often did you have seizure medicine available and take it when you were away from home?

Q4: In the last 6 months, how often did you get seizure medicine before it was finished?

Q5: In the last 6 months, how often did you plan ahead such as planning money, transport, or timing to avoid running out of seizure medicine?

Q6: In the last 6 months, when medicine was not available at the clinic, how often did you get medicine from somewhere else to avoid interruption? For example, from a private pharmacy or informal seller, through borrowing or sharing, or by travelling to another facility.

Q7: In the last 6 months, how often did you put the seizure medicine in a safe, dry place so that it would not become spoiled or lost?

Q8: In the last 6 months, how often did you keep track of how often seizures happened? For example, by counting and recording or remembering how many seizures occurred per week or per month. Market days could be used as a weekly marker.

Q9: In the last 6 months, how often did you notice or record what type of seizures happened, as best as you could?

Q10: In the last 6 months, how often did you remember or record the time of day or the situation in which a seizure happened? For example, at night, when it was cold, or when eating.

Q11: How confident are you that you have ways to get help during a seizure?

Q12: How confident are you that you ensure that others in the household know what to do during a seizure?

Q13: How confident are you that you have taught others in the household how to prevent harmful actions during seizures, such as putting objects in the person’s mouth?

Q14: How confident are you that you follow advice from the nurse or clinical officer to reduce seizures, including taking medicines, getting enough sleep, and avoiding alcohol and other triggers?

Q15: In the last 6 months, how often did you limit your exposure to open fires or cooking?

Q16: In the last 6 months, how often did you limit bathing, water, river, or well activities to reduce the risk of drowning?

Q17: In the last 6 months, how often did you prevent dangerous climbing, such as climbing trees, ladders, or high places?

Q18: In the last 6 months, how often did you make your environment safer to reduce the risk of injuries? For example, by removing sharp objects or fire from the sleeping place.

Q19: In the last 6 months, how often did you attend clinic visits?

Q20: In the last 6 months, how often did you inform a health worker if your seizures increased or changed?

Q21: In the last 6 months, how often did you seek help before the planned clinic visit—from a clinic or health worker—if your seizures became worse or continued despite treatment?

Q22: In the last 6 months, how often did you inform a health worker about any new or concerning changes noticed after starting or changing medicine, such as sleepiness, dizziness, behavioral changes, or a rash—that is, suspected medicine side effects?

Q23: In the last 6 months, how often did you ask questions when the instructions were not clear?

Q24: In the last 6 months, how often did you check with a health worker before adding other medicines or traditional remedies, or before stopping seizure medication? For example, when a traditional leader advised you to stop taking seizure medication.

Q25: In the last 6 months, how often did you make sure that at least one other trusted person knew how to help during a seizure?

Q26: In the last 6 months, how often did you inform necessary people—such as family members or people at school or work—about your epilepsy when safety required it?

Q27: In the last 6 months, how often did you talk with other people with epilepsy outside your household?

1.1 Table 1: comparing the responses of PWE with the responses of both PWE+caregiver after merging the similar questions together

1.1.1 (questions 3, 14, 20 from PWE don’t have similar questions in caregiver questionnaire and question 26 in the caregiver questionnaire does not have a similar question in the PWE)

#--------------------------------------------------
# Variables common to both questionnaires
#--------------------------------------------------

management_items <- c(
  "Q1", "Q2", "Q4", "Q5", "Q6", "Q7",
  "Q8", "Q9", "Q10", "Q11", "Q12", "Q13",
  "Q15", "Q16", "Q17", "Q18", "Q19",
  "Q21", "Q22", "Q23", "Q24", "Q25",
  "Q26", "Q27"
)


#--------------------------------------------------
#  PWE-only descriptive table
#--------------------------------------------------

tbl_pwe <- PWE %>%
  gtsummary::select(all_of(management_items)) %>%
  tbl_summary(
    digits = list(all_categorical() ~ 1),
    missing_text = "Missing"
  ) %>%
  bold_labels() %>%
  italicize_levels()


#--------------------------------------------------
#  PWE + caregiver descriptive table
#--------------------------------------------------

tbl_manag <- manag %>%
   gtsummary::select(all_of(management_items)) %>%
  tbl_summary(
    digits = list(all_categorical() ~ 1),
    missing_text = "Missing"
  ) %>%
  bold_labels() %>%
  italicize_levels()


#--------------------------------------------------
# Put tables side by side
#--------------------------------------------------

tbl_combined <- tbl_merge(
  tbls = list(tbl_pwe, tbl_manag),
  tab_spanner = c(
    "**PWE**",
    "**PWE + Caregiver**"
  )
)

tbl_combined
Characteristic
PWE
PWE + Caregiver
N = 381 N = 1841
Q1

    1 1.0 (2.6%) 7.0 (3.8%)
    4 1.0 (2.6%) 2.0 (1.1%)
    5 36.0 (94.7%) 175.0 (95.1%)
Q2

    1 1.0 (2.6%) 7.0 (3.8%)
    4 1.0 (2.6%) 3.0 (1.6%)
    5 36.0 (94.7%) 174.0 (94.6%)
Q4

    1 4.0 (10.5%) 12.0 (6.5%)
    3 2.0 (5.3%) 6.0 (3.3%)
    4 3.0 (7.9%) 15.0 (8.2%)
    5 29.0 (76.3%) 150.0 (81.5%)
    2
1.0 (0.5%)
Q5

    1 8.0 (21.1%) 25.0 (13.6%)
    3 6.0 (15.8%) 54.0 (29.3%)
    4 3.0 (7.9%) 29.0 (15.8%)
    5 21.0 (55.3%) 73.0 (39.7%)
    2
3.0 (1.6%)
Q6

    1 2.0 (6.9%) 9.0 (8.0%)
    3 2.0 (6.9%) 5.0 (4.4%)
    4 6.0 (20.7%) 23.0 (20.4%)
    5 19.0 (65.5%) 74.0 (65.5%)
    Missing 9 71
    2
2.0 (1.8%)
Q7

    5 38.0 (100.0%) 178.0 (96.7%)
    1
4.0 (2.2%)
    2
2.0 (1.1%)
Q8

    3 1.0 (2.6%) 3.0 (1.6%)
    4 1.0 (2.6%) 17.0 (9.2%)
    5 36.0 (94.7%) 159.0 (86.4%)
    1
3.0 (1.6%)
    2
2.0 (1.1%)
Q9

    4 4.0 (12.1%) 16.0 (9.4%)
    5 29.0 (87.9%) 147.0 (86.0%)
    Missing 5 13
    1
5.0 (2.9%)
    3
3.0 (1.8%)
Q10

    3 1.0 (3.0%) 1.0 (0.6%)
    4 3.0 (9.1%) 15.0 (8.7%)
    5 29.0 (87.9%) 152.0 (88.4%)
    Missing 5 12
    1
3.0 (1.7%)
    2
1.0 (0.6%)
Q11

    3 4.0 (10.5%) 11.0 (6.0%)
    4 12.0 (31.6%) 92.0 (50.3%)
    5 22.0 (57.9%) 79.0 (43.2%)
    1
1.0 (0.5%)
    Missing
1
Q12

    2 1.0 (2.6%) 1.0 (0.5%)
    3 8.0 (21.1%) 56.0 (30.6%)
    4 1.0 (2.6%) 18.0 (9.8%)
    5 28.0 (73.7%) 107.0 (58.5%)
    1
1.0 (0.5%)
    Missing
1
Q13

    3 4.0 (10.5%) 13.0 (7.1%)
    4 9.0 (23.7%) 49.0 (26.8%)
    5 25.0 (65.8%) 115.0 (62.8%)
    1
6.0 (3.3%)
    Missing
1
Q15

    1 1.0 (2.6%) 10.0 (5.4%)
    3 3.0 (7.9%) 4.0 (2.2%)
    4 3.0 (7.9%) 19.0 (10.3%)
    5 31.0 (81.6%) 150.0 (81.5%)
    2
1.0 (0.5%)
Q16

    1 2.0 (5.3%) 11.0 (6.0%)
    3 1.0 (2.6%) 4.0 (2.2%)
    4 4.0 (10.5%) 15.0 (8.2%)
    5 31.0 (81.6%) 153.0 (83.2%)
    2
1.0 (0.5%)
Q17

    1 2.0 (5.3%) 9.0 (4.9%)
    3 1.0 (2.6%) 3.0 (1.6%)
    4 1.0 (2.6%) 14.0 (7.6%)
    5 34.0 (89.5%) 158.0 (85.9%)
Q18

    1 2.0 (5.3%) 4.0 (2.2%)
    4 4.0 (10.5%) 28.0 (15.2%)
    5 32.0 (84.2%) 146.0 (79.3%)
    2
1.0 (0.5%)
    3
5.0 (2.7%)
Q19

    4 2.0 (5.3%) 5.0 (2.7%)
    5 36.0 (94.7%) 171.0 (92.9%)
    1
3.0 (1.6%)
    2
3.0 (1.6%)
    3
2.0 (1.1%)
Q21

    1 1.0 (2.9%) 4.0 (2.4%)
    3 1.0 (2.9%) 1.0 (0.6%)
    4 3.0 (8.8%) 16.0 (9.4%)
    5 29.0 (85.3%) 145.0 (85.3%)
    Missing 4 14
    2
4.0 (2.4%)
Q22

    1 1.0 (3.2%) 2.0 (1.2%)
    3 2.0 (6.5%) 10.0 (6.1%)
    4 2.0 (6.5%) 10.0 (6.1%)
    5 26.0 (83.9%) 139.0 (85.3%)
    Missing 7 21
    2
2.0 (1.2%)
Q23

    1 1.0 (2.9%) 2.0 (1.3%)
    4 1.0 (2.9%) 2.0 (1.3%)
    5 33.0 (94.3%) 145.0 (94.2%)
    Missing 3 30
    2
3.0 (1.9%)
    3
2.0 (1.3%)
Q24

    1 1.0 (25.0%) 8.0 (30.8%)
    5 3.0 (75.0%) 15.0 (57.7%)
    Missing 34 158
    4
3.0 (11.5%)
Q25

    3 1.0 (2.6%) 10.0 (5.4%)
    4 4.0 (10.5%) 21.0 (11.4%)
    5 33.0 (86.8%) 150.0 (81.5%)
    1
2.0 (1.1%)
    2
1.0 (0.5%)
Q26

    1 1.0 (2.9%) 5.0 (3.0%)
    2 1.0 (2.9%) 1.0 (0.6%)
    3 2.0 (5.7%) 14.0 (8.3%)
    4 4.0 (11.4%) 19.0 (11.2%)
    5 27.0 (77.1%) 130.0 (76.9%)
    Missing 3 15
Q27

    3 1.0 (2.7%) 32.0 (17.5%)
    4 4.0 (10.8%) 14.0 (7.7%)
    5 32.0 (86.5%) 135.0 (73.8%)
    Missing 1 1
    1
1.0 (0.5%)
    2
1.0 (0.5%)
1 n (%)

2 Confirmatory Factor analysis

2.1 Model 1

In confirmatory factor analysis, the results are usually interpreted in several connected parts. First, we examine the overall model fit, which tells us whether the proposed factor structure adequately represents the observed data; in general,we expect to see that CFI and TLI (fit measures) at least 0.95 and both RMSEA and SRMR (the errors) are at most 0.08

Second, we examine the standardized factor loadings, which show how strongly each questionnaire item is related to its intended domain; ideally, these loadings should be statistically significant and reasonably high, indicating that the items are good indicators of their constructs.

Third, we assess the correlations between the latent domains, where we expect the domains to be related but not so highly correlated, very high correlations between the domain may indicate poor discriminant validity.

Fourth, we inspect the residual variances, which represent the portion of each item that is not explained by its factor; these should remain positive, and negative values or standardized loadings above 1 may indicate an inadmissible solution such as a Heywood case.

For ordinal questionnaire data, we also examine the thresholds, which describe how respondents move between ordered response categories; these are mainly useful for understanding category use, skewness, and possible floor or ceiling effects rather than for judging model fit directly. Finally, after confirming that the factor structure is acceptable, we usually assess reliability and construct validity, including internal consistency measures such as ordinal Cronbach’s alpha or composite reliability, convergent validity using AVE, and discriminant validity to confirm that each domain is both measured consistently and sufficiently distinct from the other domains.

2.2 Model 1

items <- c(
   "Q1", "Q2", "Q4", "Q5", "Q6", "Q7",
  "Q8", "Q9", "Q10",
  "Q11", "Q12", "Q13", 
  "Q15", "Q16", "Q17", "Q18",
  "Q19", "Q21", "Q22", "Q23","Q24",
  "Q25", "Q26", "Q27"
)

model1 <- '
  DomainA =~  Q1+ Q2 
  DomainB =~  Q4 + Q5 + Q6 + Q7
  DomainC =~ Q8 + Q9 + Q10
  DomainD =~ Q11 + Q12 + Q13
  DomainE =~ Q15 + Q16 + Q17 + Q18
  DomainF =~ Q19  + Q21 + Q22 + Q23 +Q24
  DomainG =~ Q25  + Q26 + Q27 
'

fit1 <- cfa(
  model1,
  data      = manag,
  ordered   = items,
  estimator = "WLSMV",
  std.lv    = TRUE,
  missing   = "pairwise"
  
)

summary(
  fit1,
  fit.measures = TRUE,
  standardized = TRUE
)
## lavaan 0.6-19 ended normally after 44 iterations
## 
##   Estimator                                       DWLS
##   Optimization method                           NLMINB
##   Number of model parameters                       129
## 
##   Number of observations                           184
##   Number of missing patterns                        27
## 
## Model Test User Model:
##                                               Standard      Scaled
##   Test Statistic                               509.814     505.697
##   Degrees of freedom                               231         231
##   P-value (Chi-square)                           0.000       0.000
##   Scaling correction factor                                  1.384
##   Shift parameter                                          137.286
##     simple second-order correction                                
## 
## Model Test Baseline Model:
## 
##   Test statistic                             38494.663    9252.451
##   Degrees of freedom                               276         276
##   P-value                                        0.000       0.000
##   Scaling correction factor                                  4.258
## 
## User Model versus Baseline Model:
## 
##   Comparative Fit Index (CFI)                    0.993       0.969
##   Tucker-Lewis Index (TLI)                       0.991       0.963
##                                                                   
##   Robust Comparative Fit Index (CFI)                            NA
##   Robust Tucker-Lewis Index (TLI)                               NA
## 
## Root Mean Square Error of Approximation:
## 
##   RMSEA                                          0.081       0.081
##   90 Percent confidence interval - lower         0.072       0.071
##   90 Percent confidence interval - upper         0.091       0.090
##   P-value H_0: RMSEA <= 0.050                    0.000       0.000
##   P-value H_0: RMSEA >= 0.080                    0.592       0.551
##                                                                   
##   Robust RMSEA                                                  NA
##   90 Percent confidence interval - lower                        NA
##   90 Percent confidence interval - upper                        NA
##   P-value H_0: Robust RMSEA <= 0.050                            NA
##   P-value H_0: Robust RMSEA >= 0.080                            NA
## 
## Standardized Root Mean Square Residual:
## 
##   SRMR                                           0.126       0.126
## 
## Parameter Estimates:
## 
##   Parameterization                               Delta
##   Standard errors                           Robust.sem
##   Information                                 Expected
##   Information saturated (h1) model        Unstructured
## 
## Latent Variables:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   DomainA =~                                                            
##     Q1                1.015    0.008  132.800    0.000    1.015    1.015
##     Q2                0.980    0.009  106.840    0.000    0.980    0.980
##   DomainB =~                                                            
##     Q4                0.848    0.033   25.977    0.000    0.848    0.848
##     Q5                0.754    0.035   21.525    0.000    0.754    0.754
##     Q6                0.809    0.058   13.964    0.000    0.809    0.809
##     Q7                0.969    0.060   16.148    0.000    0.969    0.969
##   DomainC =~                                                            
##     Q8                0.947    0.028   33.563    0.000    0.947    0.947
##     Q9                0.859    0.050   17.247    0.000    0.859    0.859
##     Q10               0.922    0.034   26.914    0.000    0.922    0.922
##   DomainD =~                                                            
##     Q11               0.753    0.048   15.544    0.000    0.753    0.753
##     Q12               0.857    0.046   18.667    0.000    0.857    0.857
##     Q13               0.769    0.061   12.633    0.000    0.769    0.769
##   DomainE =~                                                            
##     Q15               0.928    0.024   38.633    0.000    0.928    0.928
##     Q16               0.971    0.018   55.274    0.000    0.971    0.971
##     Q17               0.910    0.027   33.927    0.000    0.910    0.910
##     Q18               0.888    0.046   19.352    0.000    0.888    0.888
##   DomainF =~                                                            
##     Q19               0.946    0.068   13.897    0.000    0.946    0.946
##     Q21               0.710    0.082    8.701    0.000    0.710    0.710
##     Q22               0.818    0.042   19.594    0.000    0.818    0.818
##     Q23               0.792    0.072   11.006    0.000    0.792    0.792
##     Q24               0.362    0.167    2.165    0.030    0.362    0.362
##   DomainG =~                                                            
##     Q25               0.844    0.038   22.402    0.000    0.844    0.844
##     Q26               0.672    0.071    9.489    0.000    0.672    0.672
##     Q27               0.669    0.041   16.438    0.000    0.669    0.669
## 
## Covariances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   DomainA ~~                                                            
##     DomainB           1.068    0.030   35.369    0.000    1.068    1.068
##     DomainC           0.898    0.043   20.949    0.000    0.898    0.898
##     DomainD           0.362    0.111    3.275    0.001    0.362    0.362
##     DomainE           0.709    0.099    7.151    0.000    0.709    0.709
##     DomainF           0.935    0.074   12.696    0.000    0.935    0.935
##     DomainG           0.531    0.126    4.218    0.000    0.531    0.531
##   DomainB ~~                                                            
##     DomainC           0.923    0.041   22.620    0.000    0.923    0.923
##     DomainD           0.436    0.053    8.158    0.000    0.436    0.436
##     DomainE           0.793    0.062   12.710    0.000    0.793    0.793
##     DomainF           0.851    0.069   12.365    0.000    0.851    0.851
##     DomainG           0.566    0.087    6.547    0.000    0.566    0.566
##   DomainC ~~                                                            
##     DomainD           0.419    0.056    7.509    0.000    0.419    0.419
##     DomainE           0.492    0.093    5.308    0.000    0.492    0.492
##     DomainF           0.785    0.084    9.297    0.000    0.785    0.785
##     DomainG           0.628    0.093    6.728    0.000    0.628    0.628
##   DomainD ~~                                                            
##     DomainE           0.268    0.080    3.356    0.001    0.268    0.268
##     DomainF           0.542    0.075    7.214    0.000    0.542    0.542
##     DomainG           0.905    0.058   15.739    0.000    0.905    0.905
##   DomainE ~~                                                            
##     DomainF           0.600    0.063    9.565    0.000    0.600    0.600
##     DomainG           0.686    0.068   10.031    0.000    0.686    0.686
##   DomainF ~~                                                            
##     DomainG           0.746    0.057   13.125    0.000    0.746    0.746
## 
## Thresholds:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##     Q1|t1            -1.774    0.171  -10.377    0.000   -1.774   -1.774
##     Q1|t2            -1.655    0.157  -10.522    0.000   -1.655   -1.655
##     Q2|t1            -1.774    0.171  -10.377    0.000   -1.774   -1.774
##     Q2|t2            -1.604    0.152  -10.548    0.000   -1.604   -1.604
##     Q4|t1            -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q4|t2            -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q4|t3            -1.263    0.125  -10.088    0.000   -1.263   -1.263
##     Q4|t4            -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q5|t1            -1.099    0.116   -9.463    0.000   -1.099   -1.099
##     Q5|t2            -1.027    0.113   -9.106    0.000   -1.027   -1.027
##     Q5|t3            -0.137    0.093   -1.470    0.142   -0.137   -0.137
##     Q5|t4             0.262    0.094    2.791    0.005    0.262    0.262
##     Q6|t1            -1.407    0.172   -8.166    0.000   -1.407   -1.407
##     Q6|t2            -1.297    0.162   -7.981    0.000   -1.297   -1.297
##     Q6|t3            -1.073    0.147   -7.319    0.000   -1.073   -1.073
##     Q6|t4            -0.398    0.122   -3.274    0.001   -0.398   -0.398
##     Q7|t1            -2.019    0.207   -9.732    0.000   -2.019   -2.019
##     Q7|t2            -1.844    0.180  -10.237    0.000   -1.844   -1.844
##     Q8|t1            -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q8|t2            -1.924    0.192  -10.032    0.000   -1.924   -1.924
##     Q8|t3            -1.712    0.164  -10.468    0.000   -1.712   -1.712
##     Q8|t4            -1.099    0.116   -9.463    0.000   -1.099   -1.099
##     Q9|t1            -1.892    0.194   -9.755    0.000   -1.892   -1.892
##     Q9|t2            -1.677    0.166  -10.127    0.000   -1.677   -1.677
##     Q9|t3            -1.079    0.119   -9.030    0.000   -1.079   -1.079
##     Q10|t1           -2.110    0.232   -9.083    0.000   -2.110   -2.110
##     Q10|t2           -1.991    0.210   -9.502    0.000   -1.991   -1.991
##     Q10|t3           -1.895    0.194   -9.777    0.000   -1.895   -1.895
##     Q10|t4           -1.194    0.125   -9.529    0.000   -1.194   -1.194
##     Q11|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q11|t2           -1.510    0.144  -10.503    0.000   -1.510   -1.510
##     Q11|t3            0.172    0.093    1.842    0.065    0.172    0.172
##     Q12|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q12|t2           -2.293    0.268   -8.568    0.000   -2.293   -2.293
##     Q12|t3           -0.476    0.097   -4.919    0.000   -0.476   -0.476
##     Q12|t4           -0.214    0.094   -2.284    0.022   -0.214   -0.214
##     Q13|t1           -1.841    0.180  -10.215    0.000   -1.841   -1.841
##     Q13|t2           -1.260    0.125  -10.051    0.000   -1.260   -1.260
##     Q13|t3           -0.328    0.095   -3.459    0.001   -0.328   -0.328
##     Q15|t1           -1.604    0.152  -10.548    0.000   -1.604   -1.604
##     Q15|t2           -1.557    0.148  -10.550    0.000   -1.557   -1.557
##     Q15|t3           -1.395    0.134  -10.399    0.000   -1.395   -1.395
##     Q15|t4           -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q16|t1           -1.557    0.148  -10.550    0.000   -1.557   -1.557
##     Q16|t2           -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q16|t3           -1.360    0.132  -10.333    0.000   -1.360   -1.360
##     Q16|t4           -0.960    0.110   -8.731    0.000   -0.960   -0.960
##     Q17|t1           -1.655    0.157  -10.522    0.000   -1.655   -1.655
##     Q17|t2           -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q17|t3           -1.074    0.115   -9.346    0.000   -1.074   -1.074
##     Q18|t1           -2.019    0.207   -9.732    0.000   -2.019   -2.019
##     Q18|t2           -1.924    0.192  -10.032    0.000   -1.924   -1.924
##     Q18|t3           -1.604    0.152  -10.548    0.000   -1.604   -1.604
##     Q18|t4           -0.819    0.105   -7.806    0.000   -0.819   -0.819
##     Q19|t1           -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q19|t2           -1.844    0.180  -10.237    0.000   -1.844   -1.844
##     Q19|t3           -1.712    0.164  -10.468    0.000   -1.712   -1.712
##     Q19|t4           -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q21|t1           -1.986    0.210   -9.462    0.000   -1.986   -1.986
##     Q21|t2           -1.674    0.166  -10.100    0.000   -1.674   -1.674
##     Q21|t3           -1.617    0.160  -10.135    0.000   -1.617   -1.617
##     Q21|t4           -1.049    0.118   -8.863    0.000   -1.049   -1.049
##     Q22|t1           -2.249    0.272   -8.281    0.000   -2.249   -2.249
##     Q22|t2           -1.968    0.211   -9.319    0.000   -1.968   -1.968
##     Q22|t3           -1.367    0.140   -9.738    0.000   -1.367   -1.367
##     Q22|t4           -1.048    0.121   -8.675    0.000   -1.048   -1.048
##     Q23|t1           -2.227    0.274   -8.141    0.000   -2.227   -2.227
##     Q23|t2           -1.846    0.197   -9.362    0.000   -1.846   -1.846
##     Q23|t3           -1.691    0.176   -9.598    0.000   -1.691   -1.691
##     Q23|t4           -1.568    0.162   -9.653    0.000   -1.568   -1.568
##     Q24|t1           -0.502    0.258   -1.946    0.052   -0.502   -0.502
##     Q24|t2           -0.194    0.248   -0.782    0.434   -0.194   -0.194
##     Q25|t1           -2.295    0.267   -8.581    0.000   -2.295   -2.295
##     Q25|t2           -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q25|t3           -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q25|t4           -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q26|t1           -1.887    0.194   -9.711    0.000   -1.887   -1.887
##     Q26|t2           -1.805    0.183   -9.889    0.000   -1.805   -1.805
##     Q26|t3           -1.183    0.126   -9.408    0.000   -1.183   -1.183
##     Q26|t4           -0.736    0.107   -6.893    0.000   -0.736   -0.736
##     Q27|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q27|t2           -2.293    0.268   -8.568    0.000   -2.293   -2.293
##     Q27|t3           -0.894    0.108   -8.295    0.000   -0.894   -0.894
##     Q27|t4           -0.636    0.100   -6.358    0.000   -0.636   -0.636
## 
## Variances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##    .Q1               -0.031                              -0.031   -0.031
##    .Q2                0.040                               0.040    0.040
##    .Q4                0.281                               0.281    0.281
##    .Q5                0.432                               0.432    0.432
##    .Q6                0.346                               0.346    0.346
##    .Q7                0.061                               0.061    0.061
##    .Q8                0.102                               0.102    0.102
##    .Q9                0.262                               0.262    0.262
##    .Q10               0.151                               0.151    0.151
##    .Q11               0.432                               0.432    0.432
##    .Q12               0.266                               0.266    0.266
##    .Q13               0.409                               0.409    0.409
##    .Q15               0.139                               0.139    0.139
##    .Q16               0.057                               0.057    0.057
##    .Q17               0.171                               0.171    0.171
##    .Q18               0.211                               0.211    0.211
##    .Q19               0.105                               0.105    0.105
##    .Q21               0.496                               0.496    0.496
##    .Q22               0.330                               0.330    0.330
##    .Q23               0.373                               0.373    0.373
##    .Q24               0.869                               0.869    0.869
##    .Q25               0.288                               0.288    0.288
##    .Q26               0.548                               0.548    0.548
##    .Q27               0.553                               0.553    0.553
##     DomainA           1.000                               1.000    1.000
##     DomainB           1.000                               1.000    1.000
##     DomainC           1.000                               1.000    1.000
##     DomainD           1.000                               1.000    1.000
##     DomainE           1.000                               1.000    1.000
##     DomainF           1.000                               1.000    1.000
##     DomainG           1.000                               1.000    1.000

The main problem concerned Domain A, which consisted of only Q1 and Q2. Both items had extremely high standardized factor loadings (Q1 = 1.015 and Q2 = 0.980), and Q1 had a negative residual variance (−0.031), indicating a Heywood case and suggesting that this two-item factor was not being estimated appropriately. In addition, the estimated correlation between Domain A and Domain B was 1.068, which exceeds the theoretical range of −1 to 1 and indicates that the two domains could not be empirically distinguished in this model.

Inspection of the item response distributions provided an important explanation for this problem. Approximately 95% of participants selected response category 5 for both Q1 and Q2, resulting in very limited variability in these items. Such extreme response concentration can produce unstable polychoric correlations and inflated factor loadings when ordinal CFA is used. Given the very similar response distributions of Q1 and Q2, their conceptual overlap, and the instability of the two-item Domain A factor, Q1 was removed and Q2 was reassigned to Domain B in Model 2. This modification is therefore based on both statistical evidence and the observed response distributions rather than solely on model-fit indices.

Additional concerns were observed in the correlations between some of the remaining domains. In particular, Domain D and Domain G were very highly correlated (r = 0.905), suggesting a potential discriminant-validity problem between these constructs. Other relatively high correlations included: Domain A–Domain C (r = 0.898), Domain A–Domain F (r = 0.935), Domain B–Domain C (r = 0.923), and Domain B–Domain F (r = 0.851). These correlations should therefore continue to be monitored after the restructuring of Domain A in Model 2.

Discriminant validity means that every domain should be distinguished from the other domain and the correlation between two domains should not be high

At the item level, most standardized factor loadings were strong. Particularly high loadings were observed for Q16 (0.971), Q7 (0.969), Q8 (0.947), and Q19 (0.946). In contrast, Q24 had a substantially weaker loading of 0.362, suggesting that it may represent its intended domain less strongly than the other items and should be examined further from both statistical and substantive perspectives. Finally, the model remained relatively complex for the available sample, with 184 participants and 129 estimated parameters, which may further contribute to instability when some ordinal response categories contain very few observations.

2.3 Model 2

model2 <- '
 
  DomainA=~  Q2+ Q4 + Q5 + Q6 + Q7
  DomainB =~ Q8 + Q9 + Q10
  DomainC =~ Q11 + Q12 + Q13
  DomainD =~ Q15 + Q16 + Q17 + Q18
  DomainE =~ Q19  + Q21 + Q22 + Q23 +Q24
  DomainF =~ Q25  + Q26 + Q27 
'

fit2 <- cfa(
  model2,
  data      = manag,
  ordered   = items,
  estimator = "WLSMV",
  std.lv    = TRUE,
  missing   = "pairwise"
  
)

summary(
  fit2,
  fit.measures = TRUE,
  standardized = TRUE
)
## lavaan 0.6-19 ended normally after 35 iterations
## 
##   Estimator                                       DWLS
##   Optimization method                           NLMINB
##   Number of model parameters                       120
## 
##   Number of observations                           184
##   Number of missing patterns                        27
## 
## Model Test User Model:
##                                               Standard      Scaled
##   Test Statistic                               488.888     478.163
##   Degrees of freedom                               215         215
##   P-value (Chi-square)                           0.000       0.000
##   Scaling correction factor                                  1.380
##   Shift parameter                                          123.957
##     simple second-order correction                                
## 
## Model Test Baseline Model:
## 
##   Test statistic                             13367.807    3526.873
##   Degrees of freedom                               253         253
##   P-value                                        0.000       0.000
##   Scaling correction factor                                  4.006
## 
## User Model versus Baseline Model:
## 
##   Comparative Fit Index (CFI)                    0.979       0.920
##   Tucker-Lewis Index (TLI)                       0.975       0.905
##                                                                   
##   Robust Comparative Fit Index (CFI)                            NA
##   Robust Tucker-Lewis Index (TLI)                               NA
## 
## Root Mean Square Error of Approximation:
## 
##   RMSEA                                          0.083       0.082
##   90 Percent confidence interval - lower         0.074       0.072
##   90 Percent confidence interval - upper         0.093       0.092
##   P-value H_0: RMSEA <= 0.050                    0.000       0.000
##   P-value H_0: RMSEA >= 0.080                    0.725       0.626
##                                                                   
##   Robust RMSEA                                                  NA
##   90 Percent confidence interval - lower                        NA
##   90 Percent confidence interval - upper                        NA
##   P-value H_0: Robust RMSEA <= 0.050                            NA
##   P-value H_0: Robust RMSEA >= 0.080                            NA
## 
## Standardized Root Mean Square Residual:
## 
##   SRMR                                           0.129       0.129
## 
## Parameter Estimates:
## 
##   Parameterization                               Delta
##   Standard errors                           Robust.sem
##   Information                                 Expected
##   Information saturated (h1) model        Unstructured
## 
## Latent Variables:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   DomainA =~                                                            
##     Q2                0.999    0.019   52.668    0.000    0.999    0.999
##     Q4                0.810    0.037   21.614    0.000    0.810    0.810
##     Q5                0.758    0.036   21.216    0.000    0.758    0.758
##     Q6                0.794    0.064   12.429    0.000    0.794    0.794
##     Q7                1.021    0.051   20.011    0.000    1.021    1.021
##   DomainB =~                                                            
##     Q8                0.947    0.029   32.457    0.000    0.947    0.947
##     Q9                0.860    0.050   17.329    0.000    0.860    0.860
##     Q10               0.921    0.034   27.499    0.000    0.921    0.921
##   DomainC =~                                                            
##     Q11               0.750    0.048   15.721    0.000    0.750    0.750
##     Q12               0.861    0.045   19.093    0.000    0.861    0.861
##     Q13               0.769    0.060   12.852    0.000    0.769    0.769
##   DomainD =~                                                            
##     Q15               0.927    0.024   38.688    0.000    0.927    0.927
##     Q16               0.971    0.018   55.329    0.000    0.971    0.971
##     Q17               0.912    0.027   34.140    0.000    0.912    0.912
##     Q18               0.886    0.045   19.592    0.000    0.886    0.886
##   DomainE =~                                                            
##     Q19               0.941    0.073   12.936    0.000    0.941    0.941
##     Q21               0.709    0.081    8.779    0.000    0.709    0.709
##     Q22               0.825    0.042   19.764    0.000    0.825    0.825
##     Q23               0.786    0.072   10.896    0.000    0.786    0.786
##     Q24               0.377    0.163    2.312    0.021    0.377    0.377
##   DomainF =~                                                            
##     Q25               0.843    0.038   22.382    0.000    0.843    0.843
##     Q26               0.675    0.069    9.718    0.000    0.675    0.675
##     Q27               0.667    0.041   16.455    0.000    0.667    0.667
## 
## Covariances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   DomainA ~~                                                            
##     DomainB           0.901    0.036   25.367    0.000    0.901    0.901
##     DomainC           0.435    0.059    7.395    0.000    0.435    0.435
##     DomainD           0.782    0.068   11.547    0.000    0.782    0.782
##     DomainE           0.882    0.069   12.772    0.000    0.882    0.882
##     DomainF           0.558    0.092    6.087    0.000    0.558    0.558
##   DomainB ~~                                                            
##     DomainC           0.419    0.056    7.518    0.000    0.419    0.419
##     DomainD           0.492    0.093    5.315    0.000    0.492    0.492
##     DomainE           0.786    0.084    9.313    0.000    0.786    0.786
##     DomainF           0.629    0.093    6.731    0.000    0.629    0.629
##   DomainC ~~                                                            
##     DomainD           0.268    0.080    3.361    0.001    0.268    0.268
##     DomainE           0.544    0.075    7.233    0.000    0.544    0.544
##     DomainF           0.905    0.057   15.820    0.000    0.905    0.905
##   DomainD ~~                                                            
##     DomainE           0.601    0.063    9.571    0.000    0.601    0.601
##     DomainF           0.687    0.068   10.087    0.000    0.687    0.687
##   DomainE ~~                                                            
##     DomainF           0.746    0.057   13.131    0.000    0.746    0.746
## 
## Thresholds:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##     Q2|t1            -1.774    0.171  -10.377    0.000   -1.774   -1.774
##     Q2|t2            -1.604    0.152  -10.548    0.000   -1.604   -1.604
##     Q4|t1            -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q4|t2            -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q4|t3            -1.263    0.125  -10.088    0.000   -1.263   -1.263
##     Q4|t4            -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q5|t1            -1.099    0.116   -9.463    0.000   -1.099   -1.099
##     Q5|t2            -1.027    0.113   -9.106    0.000   -1.027   -1.027
##     Q5|t3            -0.137    0.093   -1.470    0.142   -0.137   -0.137
##     Q5|t4             0.262    0.094    2.791    0.005    0.262    0.262
##     Q6|t1            -1.407    0.172   -8.166    0.000   -1.407   -1.407
##     Q6|t2            -1.297    0.162   -7.981    0.000   -1.297   -1.297
##     Q6|t3            -1.073    0.147   -7.319    0.000   -1.073   -1.073
##     Q6|t4            -0.398    0.122   -3.274    0.001   -0.398   -0.398
##     Q7|t1            -2.019    0.207   -9.732    0.000   -2.019   -2.019
##     Q7|t2            -1.844    0.180  -10.237    0.000   -1.844   -1.844
##     Q8|t1            -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q8|t2            -1.924    0.192  -10.032    0.000   -1.924   -1.924
##     Q8|t3            -1.712    0.164  -10.468    0.000   -1.712   -1.712
##     Q8|t4            -1.099    0.116   -9.463    0.000   -1.099   -1.099
##     Q9|t1            -1.892    0.194   -9.755    0.000   -1.892   -1.892
##     Q9|t2            -1.677    0.166  -10.127    0.000   -1.677   -1.677
##     Q9|t3            -1.079    0.119   -9.030    0.000   -1.079   -1.079
##     Q10|t1           -2.110    0.232   -9.083    0.000   -2.110   -2.110
##     Q10|t2           -1.991    0.210   -9.502    0.000   -1.991   -1.991
##     Q10|t3           -1.895    0.194   -9.777    0.000   -1.895   -1.895
##     Q10|t4           -1.194    0.125   -9.529    0.000   -1.194   -1.194
##     Q11|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q11|t2           -1.510    0.144  -10.503    0.000   -1.510   -1.510
##     Q11|t3            0.172    0.093    1.842    0.065    0.172    0.172
##     Q12|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q12|t2           -2.293    0.268   -8.568    0.000   -2.293   -2.293
##     Q12|t3           -0.476    0.097   -4.919    0.000   -0.476   -0.476
##     Q12|t4           -0.214    0.094   -2.284    0.022   -0.214   -0.214
##     Q13|t1           -1.841    0.180  -10.215    0.000   -1.841   -1.841
##     Q13|t2           -1.260    0.125  -10.051    0.000   -1.260   -1.260
##     Q13|t3           -0.328    0.095   -3.459    0.001   -0.328   -0.328
##     Q15|t1           -1.604    0.152  -10.548    0.000   -1.604   -1.604
##     Q15|t2           -1.557    0.148  -10.550    0.000   -1.557   -1.557
##     Q15|t3           -1.395    0.134  -10.399    0.000   -1.395   -1.395
##     Q15|t4           -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q16|t1           -1.557    0.148  -10.550    0.000   -1.557   -1.557
##     Q16|t2           -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q16|t3           -1.360    0.132  -10.333    0.000   -1.360   -1.360
##     Q16|t4           -0.960    0.110   -8.731    0.000   -0.960   -0.960
##     Q17|t1           -1.655    0.157  -10.522    0.000   -1.655   -1.655
##     Q17|t2           -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q17|t3           -1.074    0.115   -9.346    0.000   -1.074   -1.074
##     Q18|t1           -2.019    0.207   -9.732    0.000   -2.019   -2.019
##     Q18|t2           -1.924    0.192  -10.032    0.000   -1.924   -1.924
##     Q18|t3           -1.604    0.152  -10.548    0.000   -1.604   -1.604
##     Q18|t4           -0.819    0.105   -7.806    0.000   -0.819   -0.819
##     Q19|t1           -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q19|t2           -1.844    0.180  -10.237    0.000   -1.844   -1.844
##     Q19|t3           -1.712    0.164  -10.468    0.000   -1.712   -1.712
##     Q19|t4           -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q21|t1           -1.986    0.210   -9.462    0.000   -1.986   -1.986
##     Q21|t2           -1.674    0.166  -10.100    0.000   -1.674   -1.674
##     Q21|t3           -1.617    0.160  -10.135    0.000   -1.617   -1.617
##     Q21|t4           -1.049    0.118   -8.863    0.000   -1.049   -1.049
##     Q22|t1           -2.249    0.272   -8.281    0.000   -2.249   -2.249
##     Q22|t2           -1.968    0.211   -9.319    0.000   -1.968   -1.968
##     Q22|t3           -1.367    0.140   -9.738    0.000   -1.367   -1.367
##     Q22|t4           -1.048    0.121   -8.675    0.000   -1.048   -1.048
##     Q23|t1           -2.227    0.274   -8.141    0.000   -2.227   -2.227
##     Q23|t2           -1.846    0.197   -9.362    0.000   -1.846   -1.846
##     Q23|t3           -1.691    0.176   -9.598    0.000   -1.691   -1.691
##     Q23|t4           -1.568    0.162   -9.653    0.000   -1.568   -1.568
##     Q24|t1           -0.502    0.258   -1.946    0.052   -0.502   -0.502
##     Q24|t2           -0.194    0.248   -0.782    0.434   -0.194   -0.194
##     Q25|t1           -2.295    0.267   -8.581    0.000   -2.295   -2.295
##     Q25|t2           -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q25|t3           -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q25|t4           -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q26|t1           -1.887    0.194   -9.711    0.000   -1.887   -1.887
##     Q26|t2           -1.805    0.183   -9.889    0.000   -1.805   -1.805
##     Q26|t3           -1.183    0.126   -9.408    0.000   -1.183   -1.183
##     Q26|t4           -0.736    0.107   -6.893    0.000   -0.736   -0.736
##     Q27|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q27|t2           -2.293    0.268   -8.568    0.000   -2.293   -2.293
##     Q27|t3           -0.894    0.108   -8.295    0.000   -0.894   -0.894
##     Q27|t4           -0.636    0.100   -6.358    0.000   -0.636   -0.636
## 
## Variances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##    .Q2                0.002                               0.002    0.002
##    .Q4                0.343                               0.343    0.343
##    .Q5                0.425                               0.425    0.425
##    .Q6                0.369                               0.369    0.369
##    .Q7               -0.042                              -0.042   -0.042
##    .Q8                0.103                               0.103    0.103
##    .Q9                0.260                               0.260    0.260
##    .Q10               0.151                               0.151    0.151
##    .Q11               0.437                               0.437    0.437
##    .Q12               0.259                               0.259    0.259
##    .Q13               0.409                               0.409    0.409
##    .Q15               0.140                               0.140    0.140
##    .Q16               0.057                               0.057    0.057
##    .Q17               0.168                               0.168    0.168
##    .Q18               0.215                               0.215    0.215
##    .Q19               0.114                               0.114    0.114
##    .Q21               0.498                               0.498    0.498
##    .Q22               0.319                               0.319    0.319
##    .Q23               0.383                               0.383    0.383
##    .Q24               0.858                               0.858    0.858
##    .Q25               0.290                               0.290    0.290
##    .Q26               0.545                               0.545    0.545
##    .Q27               0.554                               0.554    0.554
##     DomainA           1.000                               1.000    1.000
##     DomainB           1.000                               1.000    1.000
##     DomainC           1.000                               1.000    1.000
##     DomainD           1.000                               1.000    1.000
##     DomainE           1.000                               1.000    1.000
##     DomainF           1.000                               1.000    1.000

Model 2 solved the original Q1 problem, but it did not improve the overall CFA fit and introduced/retained other important problems.

The most important findings are:

Global fit became worse overall. The scaled CFI decreased from about 0.969 in Model 1 to 0.920 in Model 2, and scaled TLI decreased from 0.963 to 0.905. RMSEA remained borderline/poor at 0.082 (90% CI 0.072–0.092), and SRMR remained high at 0.129. Thus, although Model 2 is simpler, it does not reproduce the observed item relationships particularly well.

Moving Q2 into the first domain removed the previous impossible correlation above 1 between the first two factors. However, Q2 now loads almost perfectly on Domain A (0.999) and has essentially zero residual variance (0.002). This is not technically a negative variance, but it still indicates that Q2 behaves unusually strongly in the model.

More importantly, Q7 now produces a Heywood case: its standardized loading is 1.021 and its residual variance is −0.042. So removing Q1 did not completely eliminate the inadmissible-estimate problem; it shifted attention to Q7 within the revised first domain. We can see in table 1 that 96.7% of the people have chosen category 5 for Q7.

There are still discriminant-validity concerns. The correlation between Domain A and Domain B is 0.901, and Domain C and Domain F is 0.905. Domain A–Domain E is also high at 0.882.

Most item loadings are strong, but Q24 remains weak at 0.377, whereas Q16 (0.971), Q8 (0.947), and Q19 (0.941) are very strong. Model 2 is somewhat simpler, with 120 parameters for 184 participants, compared with 129 parameters in Model 1, but the sample-to-model-complexity issue remains relevant.

Let’s remove Q7 in model 3 and comapre the difference

2.4 Model 3

model3 <- '
 
  DomainA=~  Q2+ Q4 + Q5 + Q6 
  DomainB =~ Q8 + Q9 + Q10
  DomainC =~ Q11 + Q12 + Q13
  DomainD =~ Q15 + Q16 + Q17 + Q18
  DomainE =~ Q19  + Q21 + Q22 + Q23 +Q24
  DomainF =~ Q25  + Q26 + Q27 
'

fit3 <- cfa(
  model3,
  data      = manag,
  ordered   = items,
  estimator = "WLSMV",
  std.lv    = TRUE,
  missing   = "pairwise"
  
)

summary(
  fit3,
  fit.measures = TRUE,
  standardized = TRUE
)
## lavaan 0.6-19 ended normally after 33 iterations
## 
##   Estimator                                       DWLS
##   Optimization method                           NLMINB
##   Number of model parameters                       117
## 
##   Number of observations                           184
##   Number of missing patterns                        27
## 
## Model Test User Model:
##                                               Standard      Scaled
##   Test Statistic                               439.777     445.256
##   Degrees of freedom                               194         194
##   P-value (Chi-square)                           0.000       0.000
##   Scaling correction factor                                  1.297
##   Shift parameter                                          106.067
##     simple second-order correction                                
## 
## Model Test Baseline Model:
## 
##   Test statistic                             10901.805    3098.184
##   Degrees of freedom                               231         231
##   P-value                                        0.000       0.000
##   Scaling correction factor                                  3.722
## 
## User Model versus Baseline Model:
## 
##   Comparative Fit Index (CFI)                    0.977       0.912
##   Tucker-Lewis Index (TLI)                       0.973       0.896
##                                                                   
##   Robust Comparative Fit Index (CFI)                            NA
##   Robust Tucker-Lewis Index (TLI)                               NA
## 
## Root Mean Square Error of Approximation:
## 
##   RMSEA                                          0.083       0.084
##   90 Percent confidence interval - lower         0.073       0.074
##   90 Percent confidence interval - upper         0.094       0.094
##   P-value H_0: RMSEA <= 0.050                    0.000       0.000
##   P-value H_0: RMSEA >= 0.080                    0.703       0.752
##                                                                   
##   Robust RMSEA                                                  NA
##   90 Percent confidence interval - lower                        NA
##   90 Percent confidence interval - upper                        NA
##   P-value H_0: Robust RMSEA <= 0.050                            NA
##   P-value H_0: Robust RMSEA >= 0.080                            NA
## 
## Standardized Root Mean Square Residual:
## 
##   SRMR                                           0.126       0.126
## 
## Parameter Estimates:
## 
##   Parameterization                               Delta
##   Standard errors                           Robust.sem
##   Information                                 Expected
##   Information saturated (h1) model        Unstructured
## 
## Latent Variables:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   DomainA =~                                                            
##     Q2                1.094    0.037   29.377    0.000    1.094    1.094
##     Q4                0.833    0.040   20.556    0.000    0.833    0.833
##     Q5                0.814    0.036   22.930    0.000    0.814    0.814
##     Q6                0.824    0.066   12.574    0.000    0.824    0.824
##   DomainB =~                                                            
##     Q8                0.931    0.033   27.819    0.000    0.931    0.931
##     Q9                0.867    0.053   16.442    0.000    0.867    0.867
##     Q10               0.931    0.041   22.575    0.000    0.931    0.931
##   DomainC =~                                                            
##     Q11               0.753    0.048   15.616    0.000    0.753    0.753
##     Q12               0.859    0.045   18.946    0.000    0.859    0.859
##     Q13               0.767    0.059   13.029    0.000    0.767    0.767
##   DomainD =~                                                            
##     Q15               0.927    0.024   37.995    0.000    0.927    0.927
##     Q16               0.972    0.018   54.679    0.000    0.972    0.972
##     Q17               0.913    0.027   34.311    0.000    0.913    0.913
##     Q18               0.884    0.045   19.731    0.000    0.884    0.884
##   DomainE =~                                                            
##     Q19               0.936    0.075   12.547    0.000    0.936    0.936
##     Q21               0.711    0.081    8.811    0.000    0.711    0.711
##     Q22               0.829    0.041   20.070    0.000    0.829    0.829
##     Q23               0.782    0.072   10.859    0.000    0.782    0.782
##     Q24               0.385    0.160    2.403    0.016    0.385    0.385
##   DomainF =~                                                            
##     Q25               0.841    0.038   22.026    0.000    0.841    0.841
##     Q26               0.676    0.069    9.860    0.000    0.676    0.676
##     Q27               0.668    0.041   16.394    0.000    0.668    0.668
## 
## Covariances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   DomainA ~~                                                            
##     DomainB           0.785    0.057   13.865    0.000    0.785    0.785
##     DomainC           0.355    0.070    5.037    0.000    0.355    0.355
##     DomainD           0.757    0.062   12.310    0.000    0.757    0.757
##     DomainE           0.835    0.064   12.944    0.000    0.835    0.835
##     DomainF           0.476    0.088    5.423    0.000    0.476    0.476
##   DomainB ~~                                                            
##     DomainC           0.418    0.056    7.510    0.000    0.418    0.418
##     DomainD           0.494    0.093    5.316    0.000    0.494    0.494
##     DomainE           0.788    0.084    9.338    0.000    0.788    0.788
##     DomainF           0.630    0.094    6.718    0.000    0.630    0.630
##   DomainC ~~                                                            
##     DomainD           0.268    0.080    3.357    0.001    0.268    0.268
##     DomainE           0.544    0.075    7.277    0.000    0.544    0.544
##     DomainF           0.905    0.057   15.870    0.000    0.905    0.905
##   DomainD ~~                                                            
##     DomainE           0.602    0.063    9.594    0.000    0.602    0.602
##     DomainF           0.687    0.068   10.086    0.000    0.687    0.687
##   DomainE ~~                                                            
##     DomainF           0.746    0.057   13.128    0.000    0.746    0.746
## 
## Thresholds:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##     Q2|t1            -1.774    0.171  -10.377    0.000   -1.774   -1.774
##     Q2|t2            -1.604    0.152  -10.548    0.000   -1.604   -1.604
##     Q4|t1            -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q4|t2            -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q4|t3            -1.263    0.125  -10.088    0.000   -1.263   -1.263
##     Q4|t4            -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q5|t1            -1.099    0.116   -9.463    0.000   -1.099   -1.099
##     Q5|t2            -1.027    0.113   -9.106    0.000   -1.027   -1.027
##     Q5|t3            -0.137    0.093   -1.470    0.142   -0.137   -0.137
##     Q5|t4             0.262    0.094    2.791    0.005    0.262    0.262
##     Q6|t1            -1.407    0.172   -8.166    0.000   -1.407   -1.407
##     Q6|t2            -1.297    0.162   -7.981    0.000   -1.297   -1.297
##     Q6|t3            -1.073    0.147   -7.319    0.000   -1.073   -1.073
##     Q6|t4            -0.398    0.122   -3.274    0.001   -0.398   -0.398
##     Q8|t1            -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q8|t2            -1.924    0.192  -10.032    0.000   -1.924   -1.924
##     Q8|t3            -1.712    0.164  -10.468    0.000   -1.712   -1.712
##     Q8|t4            -1.099    0.116   -9.463    0.000   -1.099   -1.099
##     Q9|t1            -1.892    0.194   -9.755    0.000   -1.892   -1.892
##     Q9|t2            -1.677    0.166  -10.127    0.000   -1.677   -1.677
##     Q9|t3            -1.079    0.119   -9.030    0.000   -1.079   -1.079
##     Q10|t1           -2.110    0.232   -9.083    0.000   -2.110   -2.110
##     Q10|t2           -1.991    0.210   -9.502    0.000   -1.991   -1.991
##     Q10|t3           -1.895    0.194   -9.777    0.000   -1.895   -1.895
##     Q10|t4           -1.194    0.125   -9.529    0.000   -1.194   -1.194
##     Q11|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q11|t2           -1.510    0.144  -10.503    0.000   -1.510   -1.510
##     Q11|t3            0.172    0.093    1.842    0.065    0.172    0.172
##     Q12|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q12|t2           -2.293    0.268   -8.568    0.000   -2.293   -2.293
##     Q12|t3           -0.476    0.097   -4.919    0.000   -0.476   -0.476
##     Q12|t4           -0.214    0.094   -2.284    0.022   -0.214   -0.214
##     Q13|t1           -1.841    0.180  -10.215    0.000   -1.841   -1.841
##     Q13|t2           -1.260    0.125  -10.051    0.000   -1.260   -1.260
##     Q13|t3           -0.328    0.095   -3.459    0.001   -0.328   -0.328
##     Q15|t1           -1.604    0.152  -10.548    0.000   -1.604   -1.604
##     Q15|t2           -1.557    0.148  -10.550    0.000   -1.557   -1.557
##     Q15|t3           -1.395    0.134  -10.399    0.000   -1.395   -1.395
##     Q15|t4           -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q16|t1           -1.557    0.148  -10.550    0.000   -1.557   -1.557
##     Q16|t2           -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q16|t3           -1.360    0.132  -10.333    0.000   -1.360   -1.360
##     Q16|t4           -0.960    0.110   -8.731    0.000   -0.960   -0.960
##     Q17|t1           -1.655    0.157  -10.522    0.000   -1.655   -1.655
##     Q17|t2           -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q17|t3           -1.074    0.115   -9.346    0.000   -1.074   -1.074
##     Q18|t1           -2.019    0.207   -9.732    0.000   -2.019   -2.019
##     Q18|t2           -1.924    0.192  -10.032    0.000   -1.924   -1.924
##     Q18|t3           -1.604    0.152  -10.548    0.000   -1.604   -1.604
##     Q18|t4           -0.819    0.105   -7.806    0.000   -0.819   -0.819
##     Q19|t1           -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q19|t2           -1.844    0.180  -10.237    0.000   -1.844   -1.844
##     Q19|t3           -1.712    0.164  -10.468    0.000   -1.712   -1.712
##     Q19|t4           -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q21|t1           -1.986    0.210   -9.462    0.000   -1.986   -1.986
##     Q21|t2           -1.674    0.166  -10.100    0.000   -1.674   -1.674
##     Q21|t3           -1.617    0.160  -10.135    0.000   -1.617   -1.617
##     Q21|t4           -1.049    0.118   -8.863    0.000   -1.049   -1.049
##     Q22|t1           -2.249    0.272   -8.281    0.000   -2.249   -2.249
##     Q22|t2           -1.968    0.211   -9.319    0.000   -1.968   -1.968
##     Q22|t3           -1.367    0.140   -9.738    0.000   -1.367   -1.367
##     Q22|t4           -1.048    0.121   -8.675    0.000   -1.048   -1.048
##     Q23|t1           -2.227    0.274   -8.141    0.000   -2.227   -2.227
##     Q23|t2           -1.846    0.197   -9.362    0.000   -1.846   -1.846
##     Q23|t3           -1.691    0.176   -9.598    0.000   -1.691   -1.691
##     Q23|t4           -1.568    0.162   -9.653    0.000   -1.568   -1.568
##     Q24|t1           -0.502    0.258   -1.946    0.052   -0.502   -0.502
##     Q24|t2           -0.194    0.248   -0.782    0.434   -0.194   -0.194
##     Q25|t1           -2.295    0.267   -8.581    0.000   -2.295   -2.295
##     Q25|t2           -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q25|t3           -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q25|t4           -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q26|t1           -1.887    0.194   -9.711    0.000   -1.887   -1.887
##     Q26|t2           -1.805    0.183   -9.889    0.000   -1.805   -1.805
##     Q26|t3           -1.183    0.126   -9.408    0.000   -1.183   -1.183
##     Q26|t4           -0.736    0.107   -6.893    0.000   -0.736   -0.736
##     Q27|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q27|t2           -2.293    0.268   -8.568    0.000   -2.293   -2.293
##     Q27|t3           -0.894    0.108   -8.295    0.000   -0.894   -0.894
##     Q27|t4           -0.636    0.100   -6.358    0.000   -0.636   -0.636
## 
## Variances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##    .Q2               -0.197                              -0.197   -0.197
##    .Q4                0.307                               0.307    0.307
##    .Q5                0.337                               0.337    0.337
##    .Q6                0.321                               0.321    0.321
##    .Q8                0.132                               0.132    0.132
##    .Q9                0.248                               0.248    0.248
##    .Q10               0.133                               0.133    0.133
##    .Q11               0.433                               0.433    0.433
##    .Q12               0.262                               0.262    0.262
##    .Q13               0.412                               0.412    0.412
##    .Q15               0.141                               0.141    0.141
##    .Q16               0.056                               0.056    0.056
##    .Q17               0.167                               0.167    0.167
##    .Q18               0.219                               0.219    0.219
##    .Q19               0.123                               0.123    0.123
##    .Q21               0.495                               0.495    0.495
##    .Q22               0.313                               0.313    0.313
##    .Q23               0.389                               0.389    0.389
##    .Q24               0.851                               0.851    0.851
##    .Q25               0.292                               0.292    0.292
##    .Q26               0.543                               0.543    0.543
##    .Q27               0.554                               0.554    0.554
##     DomainA           1.000                               1.000    1.000
##     DomainB           1.000                               1.000    1.000
##     DomainC           1.000                               1.000    1.000
##     DomainD           1.000                               1.000    1.000
##     DomainE           1.000                               1.000    1.000
##     DomainF           1.000                               1.000    1.000

The scaled CFI is now 0.912, TLI 0.896, RMSEA 0.084 (90% CI 0.074–0.094), and SRMR 0.126. Therefore, removing Q7 did not improve overall model fit; CFI, TLI, and RMSEA became slightly worse, while SRMR improved only minimally and remains well above the usual 0.08 threshold.

More importantly, there is still a Heywood case, but now it involves Q2. Its standardized loading increased from 0.999 in Model 2 to 1.094, which is above 1, and its residual variance is now −0.197. This is actually a stronger warning than the Q7 problem in Model 2. So Q7 itself was probably not the fundamental source of the instability.

There is one useful improvement: the correlations involving the revised first domain decreased. For example, Domain A–Domain B fell from 0.901 to 0.785, and Domain A–Domain E fell from 0.882 to 0.835. Thus, removing Q7 improved the separation of Domain A from some other domains. However, Domain C–Domain F remains extremely high at 0.905, so that discriminant-validity issue is completely unchanged.

Most of the remaining loadings are strong. Q4–Q6 now load 0.833, 0.814, and 0.824 on Domain A, respectively. Q16 remains very strong at 0.972. Q24 remains the weakest item, with a standardized loading of only 0.385

I will remove Q2 in model 4

2.5 Model 4

model4 <- '
 
  DomainA =~ Q4 + Q5 + Q6 
  DomainB =~ Q8 + Q9 + Q10
  DomainC =~ Q11 + Q12 + Q13
  DomainD =~ Q15 + Q16 + Q17 + Q18
  DomainE =~ Q19  + Q21 + Q22 + Q23 +Q24
  DomainF =~ Q25  + Q26 + Q27 

'

fit4 <- cfa(
  model4,
  data      = manag,
  ordered   = items,
  estimator = "WLSMV",
  std.lv    = TRUE,
  missing   = "pairwise"
  
)

summary(
  fit4,
  fit.measures = TRUE,
  standardized = TRUE
)
## lavaan 0.6-19 ended normally after 28 iterations
## 
##   Estimator                                       DWLS
##   Optimization method                           NLMINB
##   Number of model parameters                       114
## 
##   Number of observations                           184
##   Number of missing patterns                        27
## 
## Model Test User Model:
##                                               Standard      Scaled
##   Test Statistic                               426.691     434.786
##   Degrees of freedom                               174         174
##   P-value (Chi-square)                           0.000       0.000
##   Scaling correction factor                                  1.241
##   Shift parameter                                           91.080
##     simple second-order correction                                
## 
## Model Test Baseline Model:
## 
##   Test statistic                              9472.306    2833.183
##   Degrees of freedom                               210         210
##   P-value                                        0.000       0.000
##   Scaling correction factor                                  3.531
## 
## User Model versus Baseline Model:
## 
##   Comparative Fit Index (CFI)                    0.973       0.901
##   Tucker-Lewis Index (TLI)                       0.967       0.880
##                                                                   
##   Robust Comparative Fit Index (CFI)                            NA
##   Robust Tucker-Lewis Index (TLI)                               NA
## 
## Root Mean Square Error of Approximation:
## 
##   RMSEA                                          0.089       0.090
##   90 Percent confidence interval - lower         0.078       0.080
##   90 Percent confidence interval - upper         0.100       0.101
##   P-value H_0: RMSEA <= 0.050                    0.000       0.000
##   P-value H_0: RMSEA >= 0.080                    0.921       0.948
##                                                                   
##   Robust RMSEA                                                  NA
##   90 Percent confidence interval - lower                        NA
##   90 Percent confidence interval - upper                        NA
##   P-value H_0: Robust RMSEA <= 0.050                            NA
##   P-value H_0: Robust RMSEA >= 0.080                            NA
## 
## Standardized Root Mean Square Residual:
## 
##   SRMR                                           0.131       0.131
## 
## Parameter Estimates:
## 
##   Parameterization                               Delta
##   Standard errors                           Robust.sem
##   Information                                 Expected
##   Information saturated (h1) model        Unstructured
## 
## Latent Variables:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   DomainA =~                                                            
##     Q4                0.850    0.046   18.357    0.000    0.850    0.850
##     Q5                0.816    0.035   23.583    0.000    0.816    0.816
##     Q6                0.821    0.070   11.718    0.000    0.821    0.821
##   DomainB =~                                                            
##     Q8                0.927    0.037   25.230    0.000    0.927    0.927
##     Q9                0.877    0.053   16.608    0.000    0.877    0.877
##     Q10               0.923    0.038   24.193    0.000    0.923    0.923
##   DomainC =~                                                            
##     Q11               0.751    0.048   15.752    0.000    0.751    0.751
##     Q12               0.862    0.045   19.203    0.000    0.862    0.862
##     Q13               0.766    0.058   13.216    0.000    0.766    0.766
##   DomainD =~                                                            
##     Q15               0.925    0.025   37.459    0.000    0.925    0.925
##     Q16               0.972    0.018   53.874    0.000    0.972    0.972
##     Q17               0.914    0.027   34.272    0.000    0.914    0.914
##     Q18               0.886    0.044   19.949    0.000    0.886    0.886
##   DomainE =~                                                            
##     Q19               0.929    0.084   11.096    0.000    0.929    0.929
##     Q21               0.712    0.079    9.001    0.000    0.712    0.712
##     Q22               0.843    0.041   20.444    0.000    0.843    0.843
##     Q23               0.765    0.074   10.388    0.000    0.765    0.765
##     Q24               0.389    0.160    2.436    0.015    0.389    0.389
##   DomainF =~                                                            
##     Q25               0.842    0.038   22.010    0.000    0.842    0.842
##     Q26               0.676    0.068   10.004    0.000    0.676    0.676
##     Q27               0.667    0.041   16.373    0.000    0.667    0.667
## 
## Covariances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   DomainA ~~                                                            
##     DomainB           0.725    0.070   10.376    0.000    0.725    0.725
##     DomainC           0.349    0.068    5.162    0.000    0.349    0.349
##     DomainD           0.787    0.060   13.128    0.000    0.787    0.787
##     DomainE           0.813    0.070   11.640    0.000    0.813    0.813
##     DomainF           0.473    0.086    5.512    0.000    0.473    0.473
##   DomainB ~~                                                            
##     DomainC           0.420    0.056    7.510    0.000    0.420    0.420
##     DomainD           0.495    0.093    5.322    0.000    0.495    0.495
##     DomainE           0.789    0.084    9.342    0.000    0.789    0.789
##     DomainF           0.631    0.094    6.720    0.000    0.631    0.631
##   DomainC ~~                                                            
##     DomainD           0.268    0.080    3.369    0.001    0.268    0.268
##     DomainE           0.546    0.075    7.311    0.000    0.546    0.546
##     DomainF           0.904    0.057   15.925    0.000    0.904    0.904
##   DomainD ~~                                                            
##     DomainE           0.605    0.063    9.553    0.000    0.605    0.605
##     DomainF           0.687    0.068   10.119    0.000    0.687    0.687
##   DomainE ~~                                                            
##     DomainF           0.746    0.057   13.103    0.000    0.746    0.746
## 
## Thresholds:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##     Q4|t1            -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q4|t2            -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q4|t3            -1.263    0.125  -10.088    0.000   -1.263   -1.263
##     Q4|t4            -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q5|t1            -1.099    0.116   -9.463    0.000   -1.099   -1.099
##     Q5|t2            -1.027    0.113   -9.106    0.000   -1.027   -1.027
##     Q5|t3            -0.137    0.093   -1.470    0.142   -0.137   -0.137
##     Q5|t4             0.262    0.094    2.791    0.005    0.262    0.262
##     Q6|t1            -1.407    0.172   -8.166    0.000   -1.407   -1.407
##     Q6|t2            -1.297    0.162   -7.981    0.000   -1.297   -1.297
##     Q6|t3            -1.073    0.147   -7.319    0.000   -1.073   -1.073
##     Q6|t4            -0.398    0.122   -3.274    0.001   -0.398   -0.398
##     Q8|t1            -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q8|t2            -1.924    0.192  -10.032    0.000   -1.924   -1.924
##     Q8|t3            -1.712    0.164  -10.468    0.000   -1.712   -1.712
##     Q8|t4            -1.099    0.116   -9.463    0.000   -1.099   -1.099
##     Q9|t1            -1.892    0.194   -9.755    0.000   -1.892   -1.892
##     Q9|t2            -1.677    0.166  -10.127    0.000   -1.677   -1.677
##     Q9|t3            -1.079    0.119   -9.030    0.000   -1.079   -1.079
##     Q10|t1           -2.110    0.232   -9.083    0.000   -2.110   -2.110
##     Q10|t2           -1.991    0.210   -9.502    0.000   -1.991   -1.991
##     Q10|t3           -1.895    0.194   -9.777    0.000   -1.895   -1.895
##     Q10|t4           -1.194    0.125   -9.529    0.000   -1.194   -1.194
##     Q11|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q11|t2           -1.510    0.144  -10.503    0.000   -1.510   -1.510
##     Q11|t3            0.172    0.093    1.842    0.065    0.172    0.172
##     Q12|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q12|t2           -2.293    0.268   -8.568    0.000   -2.293   -2.293
##     Q12|t3           -0.476    0.097   -4.919    0.000   -0.476   -0.476
##     Q12|t4           -0.214    0.094   -2.284    0.022   -0.214   -0.214
##     Q13|t1           -1.841    0.180  -10.215    0.000   -1.841   -1.841
##     Q13|t2           -1.260    0.125  -10.051    0.000   -1.260   -1.260
##     Q13|t3           -0.328    0.095   -3.459    0.001   -0.328   -0.328
##     Q15|t1           -1.604    0.152  -10.548    0.000   -1.604   -1.604
##     Q15|t2           -1.557    0.148  -10.550    0.000   -1.557   -1.557
##     Q15|t3           -1.395    0.134  -10.399    0.000   -1.395   -1.395
##     Q15|t4           -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q16|t1           -1.557    0.148  -10.550    0.000   -1.557   -1.557
##     Q16|t2           -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q16|t3           -1.360    0.132  -10.333    0.000   -1.360   -1.360
##     Q16|t4           -0.960    0.110   -8.731    0.000   -0.960   -0.960
##     Q17|t1           -1.655    0.157  -10.522    0.000   -1.655   -1.655
##     Q17|t2           -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q17|t3           -1.074    0.115   -9.346    0.000   -1.074   -1.074
##     Q18|t1           -2.019    0.207   -9.732    0.000   -2.019   -2.019
##     Q18|t2           -1.924    0.192  -10.032    0.000   -1.924   -1.924
##     Q18|t3           -1.604    0.152  -10.548    0.000   -1.604   -1.604
##     Q18|t4           -0.819    0.105   -7.806    0.000   -0.819   -0.819
##     Q19|t1           -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q19|t2           -1.844    0.180  -10.237    0.000   -1.844   -1.844
##     Q19|t3           -1.712    0.164  -10.468    0.000   -1.712   -1.712
##     Q19|t4           -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q21|t1           -1.986    0.210   -9.462    0.000   -1.986   -1.986
##     Q21|t2           -1.674    0.166  -10.100    0.000   -1.674   -1.674
##     Q21|t3           -1.617    0.160  -10.135    0.000   -1.617   -1.617
##     Q21|t4           -1.049    0.118   -8.863    0.000   -1.049   -1.049
##     Q22|t1           -2.249    0.272   -8.281    0.000   -2.249   -2.249
##     Q22|t2           -1.968    0.211   -9.319    0.000   -1.968   -1.968
##     Q22|t3           -1.367    0.140   -9.738    0.000   -1.367   -1.367
##     Q22|t4           -1.048    0.121   -8.675    0.000   -1.048   -1.048
##     Q23|t1           -2.227    0.274   -8.141    0.000   -2.227   -2.227
##     Q23|t2           -1.846    0.197   -9.362    0.000   -1.846   -1.846
##     Q23|t3           -1.691    0.176   -9.598    0.000   -1.691   -1.691
##     Q23|t4           -1.568    0.162   -9.653    0.000   -1.568   -1.568
##     Q24|t1           -0.502    0.258   -1.946    0.052   -0.502   -0.502
##     Q24|t2           -0.194    0.248   -0.782    0.434   -0.194   -0.194
##     Q25|t1           -2.295    0.267   -8.581    0.000   -2.295   -2.295
##     Q25|t2           -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q25|t3           -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q25|t4           -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q26|t1           -1.887    0.194   -9.711    0.000   -1.887   -1.887
##     Q26|t2           -1.805    0.183   -9.889    0.000   -1.805   -1.805
##     Q26|t3           -1.183    0.126   -9.408    0.000   -1.183   -1.183
##     Q26|t4           -0.736    0.107   -6.893    0.000   -0.736   -0.736
##     Q27|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q27|t2           -2.293    0.268   -8.568    0.000   -2.293   -2.293
##     Q27|t3           -0.894    0.108   -8.295    0.000   -0.894   -0.894
##     Q27|t4           -0.636    0.100   -6.358    0.000   -0.636   -0.636
## 
## Variances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##    .Q4                0.277                               0.277    0.277
##    .Q5                0.335                               0.335    0.335
##    .Q6                0.325                               0.325    0.325
##    .Q8                0.140                               0.140    0.140
##    .Q9                0.231                               0.231    0.231
##    .Q10               0.147                               0.147    0.147
##    .Q11               0.436                               0.436    0.436
##    .Q12               0.257                               0.257    0.257
##    .Q13               0.414                               0.414    0.414
##    .Q15               0.145                               0.145    0.145
##    .Q16               0.055                               0.055    0.055
##    .Q17               0.165                               0.165    0.165
##    .Q18               0.216                               0.216    0.216
##    .Q19               0.136                               0.136    0.136
##    .Q21               0.493                               0.493    0.493
##    .Q22               0.290                               0.290    0.290
##    .Q23               0.414                               0.414    0.414
##    .Q24               0.848                               0.848    0.848
##    .Q25               0.290                               0.290    0.290
##    .Q26               0.544                               0.544    0.544
##    .Q27               0.555                               0.555    0.555
##     DomainA           1.000                               1.000    1.000
##     DomainB           1.000                               1.000    1.000
##     DomainC           1.000                               1.000    1.000
##     DomainD           1.000                               1.000    1.000
##     DomainE           1.000                               1.000    1.000
##     DomainF           1.000                               1.000    1.000

The model fit measures are still unacceptable

To investigate where and why the CFA model was not fitting the data well after looking at the overall fit indices. Modification indices (modindices code) are diagnostic statistics that help identify possible sources of local misfit, such as an item that may also relate to another domain (cross-loading) or two items that may share additional information not explained by their common factor (correlated residuals). sort. = TRUE arranges the results from the largest modification index to the smallest, allowing us to focus first on the most important sources of misfit, while minimum.value = 10 restricts the output to relatively substantial modification indices and avoids reviewing many trivial suggestions.

modindices(fit4, sort. = TRUE, minimum.value = 10)
##         lhs op rhs      mi    epc sepc.lv sepc.all sepc.nox
## 289 DomainF =~ Q18 109.745 -0.790  -0.790   -0.790   -0.790
## 235 DomainC =~ Q18 101.107 -0.608  -0.608   -0.608   -0.608
## 273 DomainE =~ Q18  77.735 -0.742  -0.742   -0.742   -0.742
## 217 DomainB =~ Q18  65.097 -0.674  -0.674   -0.674   -0.674
## 226 DomainC =~  Q4  54.237  0.536   0.536    0.536    0.536
## 261 DomainE =~  Q4  36.997  0.994   0.994    0.994    0.994
## 301      Q4 ~~ Q12  34.833  0.446   0.446    1.670    1.670
## 277 DomainF =~  Q4  33.629  0.524   0.524    0.524    0.524
## 339      Q6 ~~ Q13  27.860 -0.448  -0.448   -1.220   -1.220
## 401     Q11 ~~ Q13  27.858 -0.368  -0.368   -0.867   -0.867
## 418     Q12 ~~ Q18  26.753 -0.409  -0.409   -1.740   -1.740
## 476     Q18 ~~ Q27  24.701 -0.350  -0.350   -1.010   -1.010
## 244 DomainD =~  Q4  19.756 -0.678  -0.678   -0.678   -0.678
## 283 DomainF =~ Q11  19.369  0.532   0.532    0.532    0.532
## 208 DomainB =~  Q4  18.128  0.601   0.601    0.601    0.601
## 228 DomainC =~  Q6  17.851 -0.327  -0.327   -0.327   -0.327
## 503     Q25 ~~ Q27  16.452 -0.408  -0.408   -1.016   -1.016
## 284 DomainF =~ Q12  15.996 -0.526  -0.526   -0.526   -0.526
## 286 DomainF =~ Q15  15.585  0.311   0.311    0.311    0.311
## 474     Q18 ~~ Q25  15.507 -0.280  -0.280   -1.118   -1.118
## 504     Q26 ~~ Q27  15.302  0.397   0.397    0.724    0.724
## 263 DomainE =~  Q6  14.546 -0.708  -0.708   -0.708   -0.708
## 271 DomainE =~ Q16  14.211  0.330   0.330    0.330    0.330
## 250 DomainD =~ Q11  14.025  0.208   0.208    0.208    0.208
## 414     Q12 ~~ Q13  13.657  0.346   0.346    1.061    1.061
## 425     Q12 ~~ Q26  13.330 -0.255  -0.255   -0.683   -0.683
## 227 DomainC =~  Q5  12.999 -0.257  -0.257   -0.257   -0.257
## 232 DomainC =~ Q15  12.369  0.222   0.222    0.222    0.222
## 215 DomainB =~ Q16  12.029  0.306   0.306    0.306    0.306
## 303      Q4 ~~ Q15  12.028 -0.241  -0.241   -1.202   -1.202
## 451     Q16 ~~ Q18  11.956  0.267   0.267    2.442    2.442
## 501     Q24 ~~ Q27  11.557  0.372   0.372    0.542    0.542
## 234 DomainC =~ Q17  11.064  0.208   0.208    0.208    0.208
## 279 DomainF =~  Q6  10.938 -0.306  -0.306   -0.306   -0.306
## 288 DomainF =~ Q17  10.839  0.259   0.259    0.259    0.259
## 287 DomainF =~ Q16  10.724  0.272   0.272    0.272    0.272
## 404     Q11 ~~ Q17  10.685  0.249   0.249    0.927    0.927
## 233 DomainC =~ Q16  10.587  0.219   0.219    0.219    0.219
## 441     Q15 ~~ Q18  10.463  0.268   0.268    1.516    1.516

Q18 has several cross-loadings on more than one domain because the wording of Q18 is more general than the other questions in the same domain.

Q15–Q17 each assess a specific safety behavior:

Q15: limiting exposure to fire/cooking Q16: limiting water-related activities Q17: preventing dangerous climbing

But Q18 is different: “How often did you make your environment safer to reduce the risk of injuries?”with examples such as removing sharp objects or fire from the sleeping place.

This is much more general and encompassing. It could reflect an overall tendency toward epilepsy self-management or risk prevention, rather than only the specific “safety in daily life” construct.

I will remove Q18 in model 5

2.6 Model 5

model5 <- '
 
  DomainA =~ Q4 + Q5 + Q6 
  DomainB =~ Q8 + Q9 + Q10
  DomainC =~ Q11 + Q12 + Q13
  DomainD =~ Q15 + Q16 + Q17 
  DomainE =~ Q19  + Q21 + Q22 + Q23 +Q24
  DomainF =~ Q25  + Q26 + Q27 

'

fit5 <- cfa(
  model5,
  data      = manag,
  ordered   = items,
  estimator = "WLSMV",
  std.lv    = TRUE,
  missing   = "pairwise"
  
)

summary(
  fit5,
  fit.measures = TRUE,
  standardized = TRUE
)
## lavaan 0.6-19 ended normally after 28 iterations
## 
##   Estimator                                       DWLS
##   Optimization method                           NLMINB
##   Number of model parameters                       109
## 
##   Number of observations                           184
##   Number of missing patterns                        27
## 
## Model Test User Model:
##                                               Standard      Scaled
##   Test Statistic                               283.515     319.693
##   Degrees of freedom                               155         155
##   P-value (Chi-square)                           0.000       0.000
##   Scaling correction factor                                  1.173
##   Shift parameter                                           77.989
##     simple second-order correction                                
## 
## Model Test Baseline Model:
## 
##   Test statistic                              8543.999    2684.484
##   Degrees of freedom                               190         190
##   P-value                                        0.000       0.000
##   Scaling correction factor                                  3.349
## 
## User Model versus Baseline Model:
## 
##   Comparative Fit Index (CFI)                    0.985       0.934
##   Tucker-Lewis Index (TLI)                       0.981       0.919
##                                                                   
##   Robust Comparative Fit Index (CFI)                            NA
##   Robust Tucker-Lewis Index (TLI)                               NA
## 
## Root Mean Square Error of Approximation:
## 
##   RMSEA                                          0.067       0.076
##   90 Percent confidence interval - lower         0.055       0.064
##   90 Percent confidence interval - upper         0.080       0.088
##   P-value H_0: RMSEA <= 0.050                    0.013       0.000
##   P-value H_0: RMSEA >= 0.080                    0.044       0.308
##                                                                   
##   Robust RMSEA                                                  NA
##   90 Percent confidence interval - lower                        NA
##   90 Percent confidence interval - upper                        NA
##   P-value H_0: Robust RMSEA <= 0.050                            NA
##   P-value H_0: Robust RMSEA >= 0.080                            NA
## 
## Standardized Root Mean Square Residual:
## 
##   SRMR                                           0.121       0.121
## 
## Parameter Estimates:
## 
##   Parameterization                               Delta
##   Standard errors                           Robust.sem
##   Information                                 Expected
##   Information saturated (h1) model        Unstructured
## 
## Latent Variables:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   DomainA =~                                                            
##     Q4                0.843    0.044   19.297    0.000    0.843    0.843
##     Q5                0.818    0.034   23.716    0.000    0.818    0.818
##     Q6                0.827    0.069   11.995    0.000    0.827    0.827
##   DomainB =~                                                            
##     Q8                0.932    0.035   26.448    0.000    0.932    0.932
##     Q9                0.872    0.052   16.870    0.000    0.872    0.872
##     Q10               0.924    0.037   24.946    0.000    0.924    0.924
##   DomainC =~                                                            
##     Q11               0.766    0.048   16.107    0.000    0.766    0.766
##     Q12               0.847    0.044   19.072    0.000    0.847    0.847
##     Q13               0.764    0.056   13.636    0.000    0.764    0.764
##   DomainD =~                                                            
##     Q15               0.945    0.025   37.777    0.000    0.945    0.945
##     Q16               0.979    0.019   52.373    0.000    0.979    0.979
##     Q17               0.936    0.026   35.386    0.000    0.936    0.936
##   DomainE =~                                                            
##     Q19               0.932    0.082   11.398    0.000    0.932    0.932
##     Q21               0.715    0.077    9.234    0.000    0.715    0.715
##     Q22               0.838    0.042   20.090    0.000    0.838    0.838
##     Q23               0.769    0.074   10.351    0.000    0.769    0.769
##     Q24               0.392    0.159    2.469    0.014    0.392    0.392
##   DomainF =~                                                            
##     Q25               0.842    0.041   20.591    0.000    0.842    0.842
##     Q26               0.708    0.066   10.689    0.000    0.708    0.708
##     Q27               0.644    0.042   15.223    0.000    0.644    0.644
## 
## Covariances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   DomainA ~~                                                            
##     DomainB           0.726    0.070   10.403    0.000    0.726    0.726
##     DomainC           0.354    0.068    5.223    0.000    0.354    0.354
##     DomainD           0.820    0.063   12.940    0.000    0.820    0.820
##     DomainE           0.812    0.070   11.672    0.000    0.812    0.812
##     DomainF           0.476    0.085    5.571    0.000    0.476    0.476
##   DomainB ~~                                                            
##     DomainC           0.418    0.056    7.493    0.000    0.418    0.418
##     DomainD           0.401    0.104    3.866    0.000    0.401    0.401
##     DomainE           0.788    0.085    9.303    0.000    0.788    0.788
##     DomainF           0.629    0.094    6.697    0.000    0.629    0.629
##   DomainC ~~                                                            
##     DomainD           0.160    0.089    1.797    0.072    0.160    0.160
##     DomainE           0.546    0.075    7.304    0.000    0.546    0.546
##     DomainF           0.906    0.057   15.956    0.000    0.906    0.906
##   DomainD ~~                                                            
##     DomainE           0.526    0.075    7.006    0.000    0.526    0.526
##     DomainF           0.505    0.085    5.946    0.000    0.505    0.505
##   DomainE ~~                                                            
##     DomainF           0.750    0.057   13.116    0.000    0.750    0.750
## 
## Thresholds:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##     Q4|t1            -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q4|t2            -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q4|t3            -1.263    0.125  -10.088    0.000   -1.263   -1.263
##     Q4|t4            -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q5|t1            -1.099    0.116   -9.463    0.000   -1.099   -1.099
##     Q5|t2            -1.027    0.113   -9.106    0.000   -1.027   -1.027
##     Q5|t3            -0.137    0.093   -1.470    0.142   -0.137   -0.137
##     Q5|t4             0.262    0.094    2.791    0.005    0.262    0.262
##     Q6|t1            -1.407    0.172   -8.166    0.000   -1.407   -1.407
##     Q6|t2            -1.297    0.162   -7.981    0.000   -1.297   -1.297
##     Q6|t3            -1.073    0.147   -7.319    0.000   -1.073   -1.073
##     Q6|t4            -0.398    0.122   -3.274    0.001   -0.398   -0.398
##     Q8|t1            -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q8|t2            -1.924    0.192  -10.032    0.000   -1.924   -1.924
##     Q8|t3            -1.712    0.164  -10.468    0.000   -1.712   -1.712
##     Q8|t4            -1.099    0.116   -9.463    0.000   -1.099   -1.099
##     Q9|t1            -1.892    0.194   -9.755    0.000   -1.892   -1.892
##     Q9|t2            -1.677    0.166  -10.127    0.000   -1.677   -1.677
##     Q9|t3            -1.079    0.119   -9.030    0.000   -1.079   -1.079
##     Q10|t1           -2.110    0.232   -9.083    0.000   -2.110   -2.110
##     Q10|t2           -1.991    0.210   -9.502    0.000   -1.991   -1.991
##     Q10|t3           -1.895    0.194   -9.777    0.000   -1.895   -1.895
##     Q10|t4           -1.194    0.125   -9.529    0.000   -1.194   -1.194
##     Q11|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q11|t2           -1.510    0.144  -10.503    0.000   -1.510   -1.510
##     Q11|t3            0.172    0.093    1.842    0.065    0.172    0.172
##     Q12|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q12|t2           -2.293    0.268   -8.568    0.000   -2.293   -2.293
##     Q12|t3           -0.476    0.097   -4.919    0.000   -0.476   -0.476
##     Q12|t4           -0.214    0.094   -2.284    0.022   -0.214   -0.214
##     Q13|t1           -1.841    0.180  -10.215    0.000   -1.841   -1.841
##     Q13|t2           -1.260    0.125  -10.051    0.000   -1.260   -1.260
##     Q13|t3           -0.328    0.095   -3.459    0.001   -0.328   -0.328
##     Q15|t1           -1.604    0.152  -10.548    0.000   -1.604   -1.604
##     Q15|t2           -1.557    0.148  -10.550    0.000   -1.557   -1.557
##     Q15|t3           -1.395    0.134  -10.399    0.000   -1.395   -1.395
##     Q15|t4           -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q16|t1           -1.557    0.148  -10.550    0.000   -1.557   -1.557
##     Q16|t2           -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q16|t3           -1.360    0.132  -10.333    0.000   -1.360   -1.360
##     Q16|t4           -0.960    0.110   -8.731    0.000   -0.960   -0.960
##     Q17|t1           -1.655    0.157  -10.522    0.000   -1.655   -1.655
##     Q17|t2           -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q17|t3           -1.074    0.115   -9.346    0.000   -1.074   -1.074
##     Q19|t1           -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q19|t2           -1.844    0.180  -10.237    0.000   -1.844   -1.844
##     Q19|t3           -1.712    0.164  -10.468    0.000   -1.712   -1.712
##     Q19|t4           -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q21|t1           -1.986    0.210   -9.462    0.000   -1.986   -1.986
##     Q21|t2           -1.674    0.166  -10.100    0.000   -1.674   -1.674
##     Q21|t3           -1.617    0.160  -10.135    0.000   -1.617   -1.617
##     Q21|t4           -1.049    0.118   -8.863    0.000   -1.049   -1.049
##     Q22|t1           -2.249    0.272   -8.281    0.000   -2.249   -2.249
##     Q22|t2           -1.968    0.211   -9.319    0.000   -1.968   -1.968
##     Q22|t3           -1.367    0.140   -9.738    0.000   -1.367   -1.367
##     Q22|t4           -1.048    0.121   -8.675    0.000   -1.048   -1.048
##     Q23|t1           -2.227    0.274   -8.141    0.000   -2.227   -2.227
##     Q23|t2           -1.846    0.197   -9.362    0.000   -1.846   -1.846
##     Q23|t3           -1.691    0.176   -9.598    0.000   -1.691   -1.691
##     Q23|t4           -1.568    0.162   -9.653    0.000   -1.568   -1.568
##     Q24|t1           -0.502    0.258   -1.946    0.052   -0.502   -0.502
##     Q24|t2           -0.194    0.248   -0.782    0.434   -0.194   -0.194
##     Q25|t1           -2.295    0.267   -8.581    0.000   -2.295   -2.295
##     Q25|t2           -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q25|t3           -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q25|t4           -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q26|t1           -1.887    0.194   -9.711    0.000   -1.887   -1.887
##     Q26|t2           -1.805    0.183   -9.889    0.000   -1.805   -1.805
##     Q26|t3           -1.183    0.126   -9.408    0.000   -1.183   -1.183
##     Q26|t4           -0.736    0.107   -6.893    0.000   -0.736   -0.736
##     Q27|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q27|t2           -2.293    0.268   -8.568    0.000   -2.293   -2.293
##     Q27|t3           -0.894    0.108   -8.295    0.000   -0.894   -0.894
##     Q27|t4           -0.636    0.100   -6.358    0.000   -0.636   -0.636
## 
## Variances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##    .Q4                0.290                               0.290    0.290
##    .Q5                0.331                               0.331    0.331
##    .Q6                0.316                               0.316    0.316
##    .Q8                0.132                               0.132    0.132
##    .Q9                0.239                               0.239    0.239
##    .Q10               0.146                               0.146    0.146
##    .Q11               0.414                               0.414    0.414
##    .Q12               0.283                               0.283    0.283
##    .Q13               0.417                               0.417    0.417
##    .Q15               0.106                               0.106    0.106
##    .Q16               0.041                               0.041    0.041
##    .Q17               0.124                               0.124    0.124
##    .Q19               0.132                               0.132    0.132
##    .Q21               0.488                               0.488    0.488
##    .Q22               0.299                               0.299    0.299
##    .Q23               0.409                               0.409    0.409
##    .Q24               0.846                               0.846    0.846
##    .Q25               0.291                               0.291    0.291
##    .Q26               0.499                               0.499    0.499
##    .Q27               0.585                               0.585    0.585
##     DomainA           1.000                               1.000    1.000
##     DomainB           1.000                               1.000    1.000
##     DomainC           1.000                               1.000    1.000
##     DomainD           1.000                               1.000    1.000
##     DomainE           1.000                               1.000    1.000
##     DomainF           1.000                               1.000    1.000

After removing Q18 from the Safety in Daily Life domain, the CFA showed a substantial improvement in overall model fit. The scaled CFI increased to 0.934 and the scaled TLI to 0.919, while the scaled RMSEA decreased to 0.076 (90% CI: 0.064–0.088). The SRMR also decreased to 0.121, although it remained above the commonly recommended threshold, indicating some residual local misfit.

The removal of Q18 was supported both statistically and conceptually: unlike Q15–Q17, which assess specific safety behaviors related to fire, water and climbing, Q18 used broader wording concerning general environmental injury prevention and had previously shown large modification indices suggesting relationships with multiple domains. Following its removal, the remaining Safety in Daily Life items showed very strong standardized factor loadings (Q15 = 0.945, Q16 = 0.979, Q17 = 0.936).

No Heywood cases were observed in the revised model. Most other items also demonstrated satisfactory to strong loadings, although Q24 remained comparatively weak (0.392). A remaining concern was the very high correlation between Domain C and Domain F (r = 0.906), suggesting limited discriminant validity between these constructs. However, because the alternative model combining these two domains produced poorer overall fit, retaining them as theoretically distinct factors appears preferable.

modindices(fit5, sort. = TRUE, minimum.value = 10)
##         lhs op rhs     mi    epc sepc.lv sepc.all sepc.nox
## 216 DomainC =~  Q4 55.839  0.518   0.518    0.518    0.518
## 265 DomainF =~  Q4 44.138  0.564   0.564    0.564    0.564
## 250 DomainE =~  Q4 35.990  0.842   0.842    0.842    0.842
## 288      Q4 ~~ Q12 33.767  0.436   0.436    1.525    1.525
## 233 DomainD =~  Q4 31.237 -0.819  -0.819   -0.819   -0.819
## 324      Q6 ~~ Q13 27.431 -0.445  -0.445   -1.227   -1.227
## 382     Q11 ~~ Q13 25.636 -0.361  -0.361   -0.869   -0.869
## 470     Q25 ~~ Q27 20.085 -0.435  -0.435   -1.053   -1.053
## 199 DomainB =~  Q4 19.089  0.530   0.530    0.530    0.530
## 218 DomainC =~  Q6 18.703 -0.329  -0.329   -0.329   -0.329
## 471     Q26 ~~ Q27 16.120  0.412   0.412    0.762    0.762
## 235 DomainD =~  Q6 15.108  0.762   0.762    0.762    0.762
## 252 DomainE =~  Q6 15.020 -0.661  -0.661   -0.661   -0.661
## 267 DomainF =~  Q6 14.557 -0.346  -0.346   -0.346   -0.346
## 271 DomainF =~ Q11 13.952  0.549   0.549    0.549    0.549
## 217 DomainC =~  Q5 13.407 -0.250  -0.250   -0.250   -0.250
## 394     Q12 ~~ Q13 11.801  0.319   0.319    0.930    0.930
## 468     Q24 ~~ Q27 11.231  0.367   0.367    0.521    0.521
## 404     Q12 ~~ Q26 11.051 -0.237  -0.237   -0.632   -0.632
## 287      Q4 ~~ Q11 10.495  0.270   0.270    0.779    0.779
## 266 DomainF =~  Q5 10.480 -0.275  -0.275   -0.275   -0.275
## 400     Q12 ~~ Q22 10.286 -0.256  -0.256   -0.881   -0.881
## 272 DomainF =~ Q12 10.228 -0.500  -0.500   -0.500   -0.500

Q4 showed a pronounced ceiling effect, with 81.5% of respondents selecting the highest response category and very sparse responses in some lower categories, particularly category 2 (0.5%). This restricted variability may contribute to unstable polychoric correlations and the large modification indices observed for Q4.

2.7 Model 6

model6 <- '
 
  DomainA =~   Q5 + Q6 
  DomainB =~ Q8 + Q9 + Q10
  DomainC =~ Q11 + Q12 + Q13
  DomainD =~ Q15 + Q16 + Q17 
  DomainE =~ Q19  + Q21 + Q22 + Q23 + Q24
  DomainF =~ Q25  + Q26 + Q27 

'

fit6 <- cfa(
  model6,
  data      = manag,
  ordered   = items,
  estimator = "WLSMV",
  std.lv    = TRUE,
  missing   = "pairwise"
  
)

summary(
  fit6,
  fit.measures = TRUE,
  standardized = TRUE
)
## lavaan 0.6-19 ended normally after 29 iterations
## 
##   Estimator                                       DWLS
##   Optimization method                           NLMINB
##   Number of model parameters                       104
## 
##   Number of observations                           184
##   Number of missing patterns                        27
## 
## Model Test User Model:
##                                               Standard      Scaled
##   Test Statistic                               192.961     236.442
##   Degrees of freedom                               137         137
##   P-value (Chi-square)                           0.001       0.000
##   Scaling correction factor                                  1.132
##   Shift parameter                                           65.926
##     simple second-order correction                                
## 
## Model Test Baseline Model:
## 
##   Test statistic                              7634.590    2478.616
##   Degrees of freedom                               171         171
##   P-value                                        0.000       0.000
##   Scaling correction factor                                  3.234
## 
## User Model versus Baseline Model:
## 
##   Comparative Fit Index (CFI)                    0.993       0.957
##   Tucker-Lewis Index (TLI)                       0.991       0.946
##                                                                   
##   Robust Comparative Fit Index (CFI)                            NA
##   Robust Tucker-Lewis Index (TLI)                               NA
## 
## Root Mean Square Error of Approximation:
## 
##   RMSEA                                          0.047       0.063
##   90 Percent confidence interval - lower         0.030       0.049
##   90 Percent confidence interval - upper         0.062       0.076
##   P-value H_0: RMSEA <= 0.050                    0.603       0.060
##   P-value H_0: RMSEA >= 0.080                    0.000       0.017
##                                                                   
##   Robust RMSEA                                                  NA
##   90 Percent confidence interval - lower                        NA
##   90 Percent confidence interval - upper                        NA
##   P-value H_0: Robust RMSEA <= 0.050                            NA
##   P-value H_0: Robust RMSEA >= 0.080                            NA
## 
## Standardized Root Mean Square Residual:
## 
##   SRMR                                           0.110       0.110
## 
## Parameter Estimates:
## 
##   Parameterization                               Delta
##   Standard errors                           Robust.sem
##   Information                                 Expected
##   Information saturated (h1) model        Unstructured
## 
## Latent Variables:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   DomainA =~                                                            
##     Q5                0.839    0.048   17.319    0.000    0.839    0.839
##     Q6                0.842    0.062   13.599    0.000    0.842    0.842
##   DomainB =~                                                            
##     Q8                0.955    0.036   26.873    0.000    0.955    0.955
##     Q9                0.868    0.052   16.591    0.000    0.868    0.868
##     Q10               0.901    0.038   23.587    0.000    0.901    0.901
##   DomainC =~                                                            
##     Q11               0.763    0.047   16.376    0.000    0.763    0.763
##     Q12               0.850    0.043   19.909    0.000    0.850    0.850
##     Q13               0.764    0.053   14.545    0.000    0.764    0.764
##   DomainD =~                                                            
##     Q15               0.941    0.026   35.791    0.000    0.941    0.941
##     Q16               0.981    0.019   51.048    0.000    0.981    0.981
##     Q17               0.939    0.027   35.264    0.000    0.939    0.939
##   DomainE =~                                                            
##     Q19               0.918    0.083   11.037    0.000    0.918    0.918
##     Q21               0.704    0.078    9.005    0.000    0.704    0.704
##     Q22               0.851    0.041   20.717    0.000    0.851    0.851
##     Q23               0.767    0.073   10.525    0.000    0.767    0.767
##     Q24               0.413    0.152    2.718    0.007    0.413    0.413
##   DomainF =~                                                            
##     Q25               0.835    0.042   19.981    0.000    0.835    0.835
##     Q26               0.711    0.066   10.842    0.000    0.711    0.711
##     Q27               0.647    0.042   15.430    0.000    0.647    0.647
## 
## Covariances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##   DomainA ~~                                                            
##     DomainB           0.723    0.085    8.476    0.000    0.723    0.723
##     DomainC           0.560    0.072    7.729    0.000    0.560    0.560
##     DomainD           0.661    0.088    7.495    0.000    0.661    0.661
##     DomainE           0.821    0.075   11.016    0.000    0.821    0.821
##     DomainF           0.484    0.088    5.518    0.000    0.484    0.484
##   DomainB ~~                                                            
##     DomainC           0.420    0.056    7.529    0.000    0.420    0.420
##     DomainD           0.398    0.103    3.865    0.000    0.398    0.398
##     DomainE           0.788    0.085    9.263    0.000    0.788    0.788
##     DomainF           0.629    0.094    6.701    0.000    0.629    0.629
##   DomainC ~~                                                            
##     DomainD           0.160    0.089    1.801    0.072    0.160    0.160
##     DomainE           0.548    0.075    7.352    0.000    0.548    0.548
##     DomainF           0.905    0.056   16.086    0.000    0.905    0.905
##   DomainD ~~                                                            
##     DomainE           0.526    0.075    6.995    0.000    0.526    0.526
##     DomainF           0.506    0.085    5.939    0.000    0.506    0.506
##   DomainE ~~                                                            
##     DomainF           0.752    0.057   13.108    0.000    0.752    0.752
## 
## Thresholds:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##     Q5|t1            -1.099    0.116   -9.463    0.000   -1.099   -1.099
##     Q5|t2            -1.027    0.113   -9.106    0.000   -1.027   -1.027
##     Q5|t3            -0.137    0.093   -1.470    0.142   -0.137   -0.137
##     Q5|t4             0.262    0.094    2.791    0.005    0.262    0.262
##     Q6|t1            -1.407    0.172   -8.166    0.000   -1.407   -1.407
##     Q6|t2            -1.297    0.162   -7.981    0.000   -1.297   -1.297
##     Q6|t3            -1.073    0.147   -7.319    0.000   -1.073   -1.073
##     Q6|t4            -0.398    0.122   -3.274    0.001   -0.398   -0.398
##     Q8|t1            -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q8|t2            -1.924    0.192  -10.032    0.000   -1.924   -1.924
##     Q8|t3            -1.712    0.164  -10.468    0.000   -1.712   -1.712
##     Q8|t4            -1.099    0.116   -9.463    0.000   -1.099   -1.099
##     Q9|t1            -1.892    0.194   -9.755    0.000   -1.892   -1.892
##     Q9|t2            -1.677    0.166  -10.127    0.000   -1.677   -1.677
##     Q9|t3            -1.079    0.119   -9.030    0.000   -1.079   -1.079
##     Q10|t1           -2.110    0.232   -9.083    0.000   -2.110   -2.110
##     Q10|t2           -1.991    0.210   -9.502    0.000   -1.991   -1.991
##     Q10|t3           -1.895    0.194   -9.777    0.000   -1.895   -1.895
##     Q10|t4           -1.194    0.125   -9.529    0.000   -1.194   -1.194
##     Q11|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q11|t2           -1.510    0.144  -10.503    0.000   -1.510   -1.510
##     Q11|t3            0.172    0.093    1.842    0.065    0.172    0.172
##     Q12|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q12|t2           -2.293    0.268   -8.568    0.000   -2.293   -2.293
##     Q12|t3           -0.476    0.097   -4.919    0.000   -0.476   -0.476
##     Q12|t4           -0.214    0.094   -2.284    0.022   -0.214   -0.214
##     Q13|t1           -1.841    0.180  -10.215    0.000   -1.841   -1.841
##     Q13|t2           -1.260    0.125  -10.051    0.000   -1.260   -1.260
##     Q13|t3           -0.328    0.095   -3.459    0.001   -0.328   -0.328
##     Q15|t1           -1.604    0.152  -10.548    0.000   -1.604   -1.604
##     Q15|t2           -1.557    0.148  -10.550    0.000   -1.557   -1.557
##     Q15|t3           -1.395    0.134  -10.399    0.000   -1.395   -1.395
##     Q15|t4           -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q16|t1           -1.557    0.148  -10.550    0.000   -1.557   -1.557
##     Q16|t2           -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q16|t3           -1.360    0.132  -10.333    0.000   -1.360   -1.360
##     Q16|t4           -0.960    0.110   -8.731    0.000   -0.960   -0.960
##     Q17|t1           -1.655    0.157  -10.522    0.000   -1.655   -1.655
##     Q17|t2           -1.512    0.144  -10.534    0.000   -1.512   -1.512
##     Q17|t3           -1.074    0.115   -9.346    0.000   -1.074   -1.074
##     Q19|t1           -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q19|t2           -1.844    0.180  -10.237    0.000   -1.844   -1.844
##     Q19|t3           -1.712    0.164  -10.468    0.000   -1.712   -1.712
##     Q19|t4           -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q21|t1           -1.986    0.210   -9.462    0.000   -1.986   -1.986
##     Q21|t2           -1.674    0.166  -10.100    0.000   -1.674   -1.674
##     Q21|t3           -1.617    0.160  -10.135    0.000   -1.617   -1.617
##     Q21|t4           -1.049    0.118   -8.863    0.000   -1.049   -1.049
##     Q22|t1           -2.249    0.272   -8.281    0.000   -2.249   -2.249
##     Q22|t2           -1.968    0.211   -9.319    0.000   -1.968   -1.968
##     Q22|t3           -1.367    0.140   -9.738    0.000   -1.367   -1.367
##     Q22|t4           -1.048    0.121   -8.675    0.000   -1.048   -1.048
##     Q23|t1           -2.227    0.274   -8.141    0.000   -2.227   -2.227
##     Q23|t2           -1.846    0.197   -9.362    0.000   -1.846   -1.846
##     Q23|t3           -1.691    0.176   -9.598    0.000   -1.691   -1.691
##     Q23|t4           -1.568    0.162   -9.653    0.000   -1.568   -1.568
##     Q24|t1           -0.502    0.258   -1.946    0.052   -0.502   -0.502
##     Q24|t2           -0.194    0.248   -0.782    0.434   -0.194   -0.194
##     Q25|t1           -2.295    0.267   -8.581    0.000   -2.295   -2.295
##     Q25|t2           -2.137    0.230   -9.285    0.000   -2.137   -2.137
##     Q25|t3           -1.471    0.140  -10.501    0.000   -1.471   -1.471
##     Q25|t4           -0.897    0.108   -8.342    0.000   -0.897   -0.897
##     Q26|t1           -1.887    0.194   -9.711    0.000   -1.887   -1.887
##     Q26|t2           -1.805    0.183   -9.889    0.000   -1.805   -1.805
##     Q26|t3           -1.183    0.126   -9.408    0.000   -1.183   -1.183
##     Q26|t4           -0.736    0.107   -6.893    0.000   -0.736   -0.736
##     Q27|t1           -2.545    0.349   -7.288    0.000   -2.545   -2.545
##     Q27|t2           -2.293    0.268   -8.568    0.000   -2.293   -2.293
##     Q27|t3           -0.894    0.108   -8.295    0.000   -0.894   -0.894
##     Q27|t4           -0.636    0.100   -6.358    0.000   -0.636   -0.636
## 
## Variances:
##                    Estimate  Std.Err  z-value  P(>|z|)   Std.lv  Std.all
##    .Q5                0.297                               0.297    0.297
##    .Q6                0.292                               0.292    0.292
##    .Q8                0.087                               0.087    0.087
##    .Q9                0.247                               0.247    0.247
##    .Q10               0.189                               0.189    0.189
##    .Q11               0.418                               0.418    0.418
##    .Q12               0.277                               0.277    0.277
##    .Q13               0.417                               0.417    0.417
##    .Q15               0.115                               0.115    0.115
##    .Q16               0.038                               0.038    0.038
##    .Q17               0.118                               0.118    0.118
##    .Q19               0.156                               0.156    0.156
##    .Q21               0.505                               0.505    0.505
##    .Q22               0.275                               0.275    0.275
##    .Q23               0.412                               0.412    0.412
##    .Q24               0.830                               0.830    0.830
##    .Q25               0.302                               0.302    0.302
##    .Q26               0.495                               0.495    0.495
##    .Q27               0.582                               0.582    0.582
##     DomainA           1.000                               1.000    1.000
##     DomainB           1.000                               1.000    1.000
##     DomainC           1.000                               1.000    1.000
##     DomainD           1.000                               1.000    1.000
##     DomainE           1.000                               1.000    1.000
##     DomainF           1.000                               1.000    1.000

Following the removal of Q4, model fit improved substantially. The scaled CFI increased to 0.957 and the scaled TLI to 0.946, while the scaled RMSEA decreased to 0.063 (90% CI: 0.049–0.076). The SRMR also improved to 0.110, although it remained above the commonly recommended threshold, suggesting some remaining local misfit.

The removal of Q4 was supported by its highly skewed response distribution, with 81.5% of respondents selecting the highest category, as well as large modification indices indicating substantial relationships with multiple domains. Following its removal, the remaining two indicators of Domain A, Q5 and Q6, showed strong standardized loadings of 0.839 and 0.842, respectively.

The remaining items generally demonstrated satisfactory to very strong loadings, with the exception of Q24, which remained comparatively weak at 0.413.

A high latent correlation between Domain C and Domain F persisted (r = 0.905), indicating limited discriminant validity between these two theoretically distinct domains.

Interpretation

Confirmatory factor analysis using WLSMV estimation supported a six-factor structure with generally acceptable model fit. The scaled comparative fit index (CFI) was 0.957, the Tucker–Lewis index (TLI) was 0.946, and the scaled root mean square error of approximation (RMSEA) was 0.063 (90% CI: 0.049–0.076). The standardized root mean square residual (SRMR) was 0.110, indicating some remaining local model misfit. Standardized factor loadings were generally strong, ranging from 0.647 to 0.981 for most indicators. Q24 was the principal exception, with a comparatively weak standardized loading of 0.413. All residual variances were positive and no standardized loading exceeded 1, indicating an admissible solution without Heywood cases. Correlations among the latent factors ranged from 0.160 to 0.905. The particularly high correlation between Domains C and F (r = 0.905) suggested limited discriminant validity between these dimensions. Nevertheless, because an alternative model combining these domains produced poorer model fit and the constructs are theoretically distinct, retaining them as separate domains was considered preferable. Overall, the revised six-factor model demonstrated satisfactory factorial validity, while the elevated SRMR, weak performance of Q24, the two-item composition of Domain A, and the high correlation between Domains C and F should be acknowledged as remaining psychometric limitations.

2.8 Figure 1. CFA of the final 6- domains model

lavaanPlot(
  model = fit6,
  coefs = TRUE,
  stand = TRUE,
  covs = TRUE,
  stars = c("latent", "covs"),
  digits = 2,
  graph_options = list(
    rankdir = "LR",
    overlap = "false"
  ),
  node_options = list(
    shape = "box",
    fontname = "Helvetica"
  ),
  edge_options = list(
    color = "black",
    fontname = "Helvetica"
  )
)

3 Reliability analysis

We expect to see that cronbach’s alpha and omega measures for every domain to be at least 0.7 and the average variance extracted (AVE) for every domain to be more than 0.5

compRelSEM(fit6)
## DomainA DomainB DomainC DomainD DomainE DomainF 
##   0.741   0.860   0.789   0.922   0.731   0.699
reliability(fit6)
##             DomainA   DomainB   DomainC   DomainD   DomainE   DomainF
## alpha            NA        NA        NA 0.9075025        NA        NA
## alpha.ord 0.8275202 0.9305316 0.8099855 0.9660125 0.8327077 0.7012064
## omega     0.7413312 0.8510297 0.7465223 0.9187148 0.6982229 0.6347317
## omega2    0.7413312 0.8510297 0.7465223 0.9187148 0.6982229 0.6347317
## omega3    0.7413312 0.8595379 0.7885224 0.9220089 0.7309306 0.6992183
## avevar    0.7057914 0.8256329 0.6292729 0.9095602 0.5643116 0.5405085

Internal consistency was generally satisfactory across the six domains. Ordinal Cronbach’s alpha coefficients ranged from 0.701 to 0.966, indicating acceptable to excellent internal consistency. Composite reliability estimates were similarly satisfactory, with omega-based coefficients ranging approximately from 0.699 to 0.922 when accounting for the measurement model. Domain D demonstrated the highest reliability, whereas Domain F showed the weakest reliability and was close to the conventional threshold for acceptability. Average variance extracted (AVE) ranged from 0.541 to 0.910 and exceeded 0.50 for all domains, providing evidence of adequate convergent validity. Overall, the results support satisfactory reliability and convergent validity of the six-domain structure, although Domain F warrants some caution because of its comparatively lower reliability.

4 Split-half reliability

For each domain, the items were divided into two halves, and the correlation between the two halves was assessed. A high correlation between the two sets of items indicates that they measure the construct consistently and therefore provides evidence of the questionnaire’s internal consistency reliability.

library(psych)

# Domain A
R_A <- psych::polychoric(manag[, c("Q5", "Q6")])$rho
splitHalf(R_A, raw = FALSE, brute = TRUE)
## Split half reliabilities  
## Call: splitHalf(r = R_A, raw = FALSE, brute = TRUE)
## 
## Maximum split half reliability (lambda 4) =  0.83
## Guttman lambda 6                          =  0.71
## Average split half reliability            =  0.83
## Guttman lambda 3 (alpha)                  =  0.83
## Guttman lambda 2                          =  0.83
## Minimum split half reliability  (beta)    =  0.83
## Average interitem r =  0.71  with median =  0.71
# Domain B
R_B <- psych::polychoric(manag[, c("Q8", "Q9", "Q10")])$rho
splitHalf(R_B, raw = FALSE, brute = TRUE)
## Split half reliabilities  
## Call: splitHalf(r = R_B, raw = FALSE, brute = TRUE)
## 
## Maximum split half reliability (lambda 4) =  0.84
## Guttman lambda 6                          =  0.9
## Average split half reliability            =  0.83
## Guttman lambda 3 (alpha)                  =  0.93
## Guttman lambda 2                          =  0.93
## Minimum split half reliability  (beta)    =  0.81
## Average interitem r =  0.82  with median =  0.81
# Domain C
R_C <- psych::polychoric(manag[, c("Q11", "Q12", "Q13")])$rho
splitHalf(R_C, raw = FALSE, brute = TRUE)
## Split half reliabilities  
## Call: splitHalf(r = R_C, raw = FALSE, brute = TRUE)
## 
## Maximum split half reliability (lambda 4) =  0.8
## Guttman lambda 6                          =  0.77
## Average split half reliability            =  0.72
## Guttman lambda 3 (alpha)                  =  0.81
## Guttman lambda 2                          =  0.81
## Minimum split half reliability  (beta)    =  0.63
## Average interitem r =  0.59  with median =  0.58
# Domain D
R_D <- psych::polychoric(manag[, c("Q15", "Q16", "Q17")])$rho
splitHalf(R_D, raw = FALSE, brute = TRUE)
## Split half reliabilities  
## Call: splitHalf(r = R_D, raw = FALSE, brute = TRUE)
## 
## Maximum split half reliability (lambda 4) =  0.88
## Guttman lambda 6                          =  0.96
## Average split half reliability            =  0.86
## Guttman lambda 3 (alpha)                  =  0.97
## Guttman lambda 2                          =  0.97
## Minimum split half reliability  (beta)    =  0.85
## Average interitem r =  0.9  with median =  0.92
# Domain E
R_E <- psych::polychoric(
  manag[, c("Q19", "Q21", "Q22", "Q23", "Q24")]
)$rho
splitHalf(R_E, raw = FALSE, brute = TRUE)
## Split half reliabilities  
## Call: splitHalf(r = R_E, raw = FALSE, brute = TRUE)
## 
## Maximum split half reliability (lambda 4) =  0.92
## Guttman lambda 6                          =  0.86
## Average split half reliability            =  0.8
## Guttman lambda 3 (alpha)                  =  0.83
## Guttman lambda 2                          =  0.85
## Minimum split half reliability  (beta)    =  0.65
## Average interitem r =  0.5  with median =  0.58
# Domain F
R_F <- psych::polychoric(manag[, c("Q25", "Q26", "Q27")])$rho
splitHalf(R_F, raw = FALSE, brute = TRUE)
## Split half reliabilities  
## Call: splitHalf(r = R_F, raw = FALSE, brute = TRUE)
## 
## Maximum split half reliability (lambda 4) =  0.83
## Guttman lambda 6                          =  0.73
## Average split half reliability            =  0.62
## Guttman lambda 3 (alpha)                  =  0.7
## Guttman lambda 2                          =  0.73
## Minimum split half reliability  (beta)    =  0.44
## Average interitem r =  0.44  with median =  0.48

Split-half reliability provided additional evidence of internal consistency across the domains. Average split-half coefficients were 0.83 for Domain A, 0.83 for Domain B, 0.72 for Domain C, 0.86 for Domain D, and 0.80 for Domain E.

Reliability was highly stable across alternative splits for Domains B and D, whereas greater variability was observed for Domains C and E. Domain D showed exceptionally high inter-item correlations (average r = 0.90), suggesting substantial homogeneity and possible item redundancy. Overall, the split-half results were consistent with the ordinal alpha and composite reliability findings and supported satisfactory internal consistency of the retained domains.

5 Convegent validity

Convergent validity means that all the items (questions) included in one domain are highly correlated with each other

Average Variance Extracted (AVE) metric tells how much of the variance in the items of a domain is explained by the latent construct, on average. An AVE around 0.50 or higher is commonly taken as evidence that the construct explains at least half of the variance in its indicators (questions).

AVE(fit6,return.df = T)
## DomainA DomainB DomainC DomainD DomainE DomainF 
##   0.706   0.826   0.629   0.910   0.564   0.541

The AVE for every domain exceeded 0.5 and this demonstrate evidence of adequate convergent validity

6 Discriminant validity

Convergent validity means that we have evidence that every domain is distinct from the other domains because we suppose that every domain measures a different construct, so we expect to see low reliability between the domains.

discriminantValidity(fit6)
##        lhs op     rhs       est    ci.lower  ci.upper  Df AIC BIC    Chisq
## 1  DomainA ~~ DomainB 0.7229679  0.55579574 0.8901401 138  NA  NA 198.8454
## 2  DomainA ~~ DomainC 0.5597477  0.41779651 0.7016989 138  NA  NA 216.8033
## 3  DomainA ~~ DomainD 0.6613662  0.48842675 0.8343056 138  NA  NA 205.3352
## 4  DomainA ~~ DomainE 0.8208498  0.67479946 0.9669002 138  NA  NA 194.1217
## 5  DomainA ~~ DomainF 0.4836148  0.31183886 0.6553907 138  NA  NA 214.6615
## 6  DomainB ~~ DomainC 0.4196631  0.31041613 0.5289102 138  NA  NA 285.6658
## 7  DomainB ~~ DomainD 0.3977083  0.19604035 0.5993763 138  NA  NA 290.0279
## 8  DomainB ~~ DomainE 0.7878262  0.62113280 0.9545197 138  NA  NA 197.3800
## 9  DomainB ~~ DomainF 0.6293857  0.44529049 0.8134810 138  NA  NA 209.7944
## 10 DomainC ~~ DomainD 0.1600292 -0.01413494 0.3341933 138  NA  NA 449.0970
## 11 DomainC ~~ DomainE 0.5479917  0.40189694 0.6940864 138  NA  NA 237.5345
## 12 DomainC ~~ DomainF 0.9051793  0.79488681 1.0154718 138  NA  NA 192.9607
## 13 DomainD ~~ DomainE 0.5261440  0.37872682 0.6735612 138  NA  NA 258.3560
## 14 DomainD ~~ DomainF 0.5060387  0.33902785 0.6730496 138  NA  NA 232.2185
## 15 DomainE ~~ DomainF 0.7519407  0.63950400 0.8643774 138  NA  NA 198.1075
##       Chisq diff Df diff   Pr(>Chisq)
## 1   4.291483e+00       1 3.830375e-02
## 2   1.939298e+01       1 1.063973e-05
## 3   7.158750e+00       1 7.459917e-03
## 4   1.104717e+00       1 2.932332e-01
## 5   2.138103e+01       1 3.764778e-06
## 6   6.564601e+01       1 5.396403e-16
## 7   2.372893e+01       1 1.109030e-06
## 8   1.926025e+00       1 1.651940e-01
## 9   8.470037e+00       1 3.610441e-03
## 10  7.584588e+01       1 3.066922e-18
## 11  2.205480e+01       1 2.649757e-06
## 12 -9.631277e-10       1 1.000000e+00
## 13  2.269532e+01       1 1.898294e-06
## 14  2.289906e+01       1 1.707356e-06
## 15  6.826933e+00       1 8.979330e-03
HTMT <- htmt(
  model6,
  data     = manag,
  ordered  = items,
  missing  = "pairwise",
  absolute = TRUE,
  htmt2    = TRUE
)

round(HTMT, 3)
##         DomanA DomanB DomanC DomanD DomanE DomanF
## DomainA  1.000                                   
## DomainB  0.721  1.000                            
## DomainC  0.540  0.408  1.000                     
## DomainD  0.606  0.355  0.166  1.000              
## DomainE  0.970  0.776  0.653  0.451  1.000       
## DomainF  0.517  0.752  1.060  0.564  1.094  1.000

Discriminant validity was supported for most pairs of latent constructs based on comparisons of estimated factor correlations with the 0.90 criterion. Twelve of the 15 domain pairs demonstrated correlations significantly below 0.90. However, discriminant validity was not clearly established between Domains A and E (r = 0.821, p = .293) or between Domains B and E (r = 0.788, p = .165). The strongest concern was observed between Domains C and F, which showed a latent correlation of 0.905 and therefore failed to demonstrate discriminant validity. Overall, the findings indicate adequate differentiation among most domains, with substantial overlap particularly between Domains C and F.