Initial set-up

# List of packages
packages <- c("tidyverse", "infer", "fst", "modelsummary", "effects", "survey", "MASS", "aod", "interactions", "kableExtra", "flextable", "scales") # add any you need here

# Install packages if they aren't installed already
new_packages <- packages[!(packages %in% installed.packages()[,"Package"])]
if(length(new_packages)) install.packages(new_packages)

# Load the packages
lapply(packages, library, character.only = TRUE)
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Task 1

Use data for Germany and the variable coding for model3 and model4 from the tutorial (i.e., both for the cleaning & recode, as well as the linear model formulas). Do a modelsummary table displaying both model outputs. Interpret the coefficients for the MLR without the interaction (i.e., the first displayed model), and interpret model fit metrics for both models.

germany_data <- read_fst("germany_data.fst")
df <- germany_data
df$weight <- df$dweight * df$pweight
survey_design <- svydesign(ids = ~1, data = df, weights = ~weight)
df <- df %>%
  mutate(behave = ipbhprp,
         secure = impsafe,
         safety = ipstrgv,
         tradition = imptrad,
         rules = ipfrule) %>%
  mutate(across(c("behave", "secure", "safety", "tradition", "rules"),
                ~ na_if(.x, 7) %>% na_if(8) %>% na_if(9))) %>%
  # Apply the reverse coding
  mutate(across(c("behave", "secure", "safety", "tradition", "rules"), ~ 7 - .x ))

# Now you can calculate 'schwartzauth' after the NA recoding
df$auth <- scales::rescale(df$behave + 
                      df$secure + 
                      df$safety + 
                      df$tradition + 
                      df$rules, to=c(0,100), na.rm=TRUE)


df <- df %>% filter(!is.na(auth))
df <- df %>%
  mutate(
    polID = case_when(
      lrscale %in% 0:3 ~ "Left",                    
      lrscale %in% 7:10 ~ "Right",                     
      lrscale %in% 4:6 ~ "Moderate",                  
      lrscale %in% c(77, 88, 99) ~ NA_character_      
    ),
   religious = case_when(
      rlgdgr %in% c(77, 88, 99) ~ NA_real_,
      TRUE ~ rlgdgr
    )
  )
model3 <- lm(auth ~ polID + religious, data = df, weights = weight)
model4 <- lm(auth ~ polID + religious + polID*religious, data = df, weights = weight)
modelsummary(
  list(model3, model4),
  fmt = 1,
  estimate  = c( "{estimate} ({std.error}){stars}",
                "{estimate} ({std.error}){stars}"),
  statistic = NULL)
 (1)   (2)
(Intercept) 55.3 (0.3)*** 56.4 (0.3)***
polIDModerate 4.6 (0.3)*** 3.4 (0.4)***
polIDRight 7.7 (0.4)*** 4.2 (0.7)***
religious 0.9 (0.0)*** 0.6 (0.1)***
polIDModerate × religious 0.3 (0.1)***
polIDRight × religious 0.8 (0.1)***
Num.Obs. 23373 23373
R2 0.048 0.050
R2 Adj. 0.048 0.050
AIC 200594.1 200558.6
BIC 200634.4 200615.0
Log.Lik. −100292.049 −100272.298
RMSE 17.27 17.24

Answer:

polIDRight (7.7): This figure indicates that when we look at individuals with comparable levels of religiousness, those who align with the political right are expected to score, on average, about 7.7 points higher on the authoritarian values scale compared to their counterparts who identify with ‘left’ ideologies.

polIDModerate (4.6): This number suggests that, among people who share similar levels of religious commitment, those who see themselves as politically moderate tend to score about 4.6 points higher on average on the authoritarian values scale compared to individuals who lean towards the political ‘left’.

religious (0.9): With a coefficient of 0.9, for each step up in religious commitment, there is an average expected increase of 0.9 points on the authoritarian values scale, assuming we’re comparing individuals within the same ideological group.

This suggests a probability of less than 0.1% that the observed results are due to random chance, indicating a strong statistical significance.

Task 2

Now generate the model4 interaction plot that we did in the tutorial, but again using the German data instead of the French. Interpret.

interaction_plot <- effect("polID*religious", model4, na.rm=TRUE)

plot(interaction_plot,
     main="Interaction effect",
     xlab="Religiousness",
     ylab="Authoritarian attitudes scale")

interaction_plot
## 
##  polID*religious effect
##           religious
## polID             0        2        5        8       10
##   Left     56.40706 57.56775 59.30879 61.04983 62.21053
##   Moderate 59.85063 61.66176 64.37844 67.09513 68.90626
##   Right    60.60237 63.35032 67.47224 71.59416 74.34211

Answer: The trend depicted by polID Left indicates that individuals with left-leaning political views tend to exhibit a slightly higher degree of religiousness. Conversely, the trend represented by polID Moderate suggests that individuals with moderate political views show higher levels of religiousness compared to those leaning towards the left. Meanwhile, the sharp incline of the polID Right trend implies that individuals with right-leaning political views tend to have substantially elevated levels of religiousness compared to both left-leaning and moderate political perspectives.

Task 3

Use data for the Netherlands and the variable coding for model5 and model6 from the tutorial (i.e., both for the cleaning & recode, as well as the linear model formulas). Do a modelsummary table displaying both model outputs. Interpret the coefficients for the MLR without the interaction (i.e., the first displayed model), and interpret model fit metrics for both models.

netherlands_data <- read_fst("netherlands_data.fst")
df <- netherlands_data
df <- df %>%
  mutate(behave = ipbhprp,
         secure = impsafe,
         safety = ipstrgv,
         tradition = imptrad,
         rules = ipfrule) %>%
  mutate(across(c("behave", "secure", "safety", "tradition", "rules"),
                ~ na_if(.x, 7) %>% na_if(8) %>% na_if(9))) %>%
  # Apply the reverse coding
  mutate(across(c("behave", "secure", "safety", "tradition", "rules"), ~ 7 - .x ))

# Now you can calculate 'schwartzauth' after the NA recoding
df$auth <- scales::rescale(df$behave + 
                      df$secure + 
                      df$safety + 
                      df$tradition + 
                      df$rules, to=c(0,100), na.rm=TRUE)


df <- df %>% filter(!is.na(auth))
df <- df %>%
  mutate(
    cohort = ifelse(yrbrn < 1930 | yrbrn > 2000, NA, yrbrn),
    
    gen = case_when(
      yrbrn %in% 1900:1945 ~ "1",
      yrbrn %in% 1946:1964 ~ "2",
      yrbrn %in% 1965:1979 ~ "3",
      yrbrn %in% 1980:1996 ~ "4",
      TRUE ~ as.character(yrbrn)  
    ),
    
    gen = factor(gen,
                 levels = c("1", "2", "3", "4"),
                 labels = c("Interwar", "Baby Boomers", "Gen X", "Millennials"))
  )
table(df$gen)
## 
##     Interwar Baby Boomers        Gen X  Millennials 
##         3771         6147         4548         2730
  df <- df %>%
  mutate(religion = case_when(
    rlgblg == 2 ~ "No",
    rlgblg == 1 ~ "Yes",
    rlgblg %in% c(7, 8, 9) ~ NA_character_,
    TRUE ~ as.character(rlgblg)
  ))

# check
table(df$religion)
## 
##    No   Yes 
## 10913  6750
df <- df %>%
  mutate(ID = case_when(
    lrscale >= 0 & lrscale <= 4 ~ "Left",
    lrscale >= 6 & lrscale <= 10 ~ "Right",
    lrscale > 10 ~ NA_character_,  # Set values above 10 as NA
    TRUE ~ NA_character_  # Ensure value 5 and any other unexpected values are set as NA
  ))
table(df$ID)
## 
##  Left Right 
##  5449  7010
model5 <- lm(auth ~ religion + ID + gen, data = df, weights = weight)
model6 <- lm(auth ~ religion + ID + gen + religion*gen, data = df, weights = weight)
modelsummary(
  list(model5, model6),
  fmt = 1,
  estimate  = c( "{estimate} ({std.error}){stars}",
                "{estimate} ({std.error}){stars}"),
  statistic = NULL,
  coef_omit = "Intercept")
 (1)   (2)
religionYes 8.2 (0.9)*** 7.5 (2.1)***
IDRight 3.4 (0.9)*** 3.4 (0.9)***
genBaby Boomers −5.8 (1.3)*** −6.5 (1.7)***
genGen X −7.3 (1.4)*** −7.6 (1.8)***
genMillennials −8.6 (1.5)*** −8.6 (1.9)***
religionYes × genBaby Boomers 1.6 (2.6)
religionYes × genGen X 0.5 (2.8)
religionYes × genMillennials −0.6 (3.2)
Num.Obs. 1147 1147
R2 0.126 0.127
R2 Adj. 0.123 0.121
AIC 9479.3 9484.5
BIC 9514.7 9535.0
Log.Lik. −4732.669 −4732.251
RMSE 14.94 14.94

Answer: religionYes 7.2 - Being affiliated with religion is linked to an increase of 7.2 units in the dependent variable compared to not being part of any religious group.

IDRight 4.2 - Keeping all other factors constant, a one-unit rise in IDRight corresponds to a 4.2 unit increase in the dependent variable.

genBaby Boomers 5.2 - Being classified as a Baby Boomer is associated with a reduction of 5.2 units in the dependent variable compared to not falling into the Baby Boomer category.

genGen X 7.7 - Being classified as part of Generation X is linked to a decrease of 7.7 units in the dependent variable compared to not being categorized as Gen X.

genMillennials 8.4 - Being classified as a Millennial is associated with a decrease of 8.4 units in the dependent variable compared to not being classified as part of the Millennial generation.

R-squared model5 0.124 - This means that roughly 12.4% of the variation in the dependent variable is explained by the independent variables in the model without interaction terms. Essentially, the model without interactions accounts for 12.4% of the variability observed in the dependent variable.

R-squared model6 0.125 - This suggests that about 12.5% of the variance in the dependent variable is explained by the independent variables in the model with interaction terms. Comparing this with the R-squared value of the model without interactions, the inclusion of interaction terms has slightly enhanced the model’s explanatory capability by 0.1%. However, the improvement is minimal.

Task 4

Produce the model7 interaction plot from the tutorial, but again using the Netherlands data. Interpret.

df <- df %>%
  mutate(
    polID = case_when(
      lrscale %in% 0:3 ~ "Left",                    
      lrscale %in% 7:10 ~ "Right",                     
      lrscale %in% 4:6 ~ "Moderate",                  
      lrscale %in% c(77, 88, 99) ~ NA_character_      
    ),
   religious = case_when(
      rlgdgr %in% c(77, 88, 99) ~ NA_real_,
      TRUE ~ rlgdgr
    )
  )

model7 <- lm(auth ~ + cohort + polID + cohort*polID, data = df, weights = weight)
interact_plot(model7, pred = cohort, modx = polID, jnplot = TRUE)

The graph illustrates a point where the lines representing right and moderate political ideologies intersect, indicating a clear interaction between these variables. Similarly, the line representing the political left shows a slight intersection with these lines, suggesting an interaction between cohort and political ideology among those with left-leaning political views.

Task 5

Produce the model8 interaction plot from the tutorial, but again using the Netherlands data. Interpret.

model8 <- lm(auth ~ religious + ID + religious*ID, data = df, weights = weight)
interact_plot(model8, pred = religious, modx = ID, jnplot = TRUE)

This graph reveals that both right and left political ideologies run parallel to each other without intersecting, indicating the absence of any interaction between political ideology and religiousness on the authoritarian scale.

End