Dyadic Data Analysis

Acknowledgment

Kenny, D. A., Kashy, D. A., & Cook, W. L. (2006). Dyadic data analysis. Guilford Press.

Visit: “David Kenny web page”

Map

Definitions

The dyad is the unit of interpersonal interaction

  • Partners
  • Friends
  • Family
  • Co-workers

Types of dyads

Distinguishable

  • There is a variable that can be used to differentiate between the two persons.

  • Husband and wife

  • First and second author

  • The advisor and PhD. Student

Indistinguishable

  • There is not a variable that can be used to differentiate between the two persons.

  • Twins

  • Best friends (mutually chosen)

  • Roommates

Dyad Variability

Between

  • Time together
  • Family income

Within

  • Time using the car (only one car)
  • Gender (heterosexual couple)

Mixed

  • Risk factor
  • Age

Interdependence

Non independence

“If the two scores from the two members of the dyad are non-independent, then those two scores are more similar to (or different from) from one another than are two scores from two people who are not members of the same dyad”.

  • More similar within the dyad than the average

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Exercise

Jamboard

Data structure

Type of models

  • Multilevel model
  • Structural Equation Model
  • Actor Partner Interdependence Model

Multilevel model

Data set

  • 10 cohabiting heterosexual couples.

Examine whether the contribution a person made to the household (a composite score based on financial contribution, as well as household labor) was associated with that person prediction for the relationship’s future - specifically, the likelihood of marriage within the next 5 years, measured as a percentage.

Cultural variation in the association.

The data

Note: women = -1 and men = 1, American = 1 and Asian =-1. Contribution is about the sample mean (so the interaction among predictors can be readily interpreted).

Things we can do

  • Estimate the mean for future.
  • Using contribution, estimate if more contributions-more positive future
  • Using culture, we can estimate differences between groups.
  • Finally, the interaction between culture, contribution and future.

Estimate a model using multiple regression

Characteristic Beta 95% CI1 p-value
(Intercept) 72 65, 79 <0.001
Contribution 0.56 -0.16, 1.3 0.12
Culture -9.5 -16, -2.6 0.010
Contribution * Culture 0.43 -0.29, 1.1 0.2
1 CI = Confidence Interval

Estimate a model using lmer (random effect)

  Future
Predictors Estimates CI p
(Intercept) 71.83 62.24 – 81.42 <0.001
Contribution 0.84 0.30 – 1.39 0.005
Culture -9.03 -18.62 – 0.55 0.063
Contribution * Culture 0.49 -0.06 – 1.04 0.077
Random Effects
σ2 43.76
τ00 Dyad 176.42
ICC 0.80
N Dyad 10
Observations 20
Marginal R2 / Conditional R2 0.468 / 0.894

Is the random effect significant?

Data: data_example
Models:
lmm_wrong: Future ~ Contribution + Culture + Contribution * Culture
lmm: Future ~ Contribution + Culture + Contribution * Culture + (1 | Dyad)
          npar    AIC    BIC  logLik deviance  Chisq Df Pr(>Chisq)   
lmm_wrong    5 168.52 173.50 -79.260   158.52                        
lmm          6 161.89 167.86 -74.943   149.89 8.6345  1   0.003299 **
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Interclass correlation

How many random effects are in this model?

Two random factors:

  • The dyadic covariance (the variance of the intercept)
  • The error variance

Compute Interclass Correlation Coefficient

Linear mixed model fit by REML ['lmerMod']
Formula: Future ~ (1 | Dyad)
   Data: data_example

REML criterion at convergence: 158.5

Scaled residuals: 
     Min       1Q   Median       3Q      Max 
-1.19559 -0.66688  0.06362  0.56923  1.33335 

Random effects:
 Groups   Name        Variance Std.Dev.
 Dyad     (Intercept) 255.5    15.983  
 Residual              82.3     9.072  
Number of obs: 20, groups:  Dyad, 10

Fixed effects:
            Estimate Std. Error t value
(Intercept)   71.100      5.446   13.05

255.5 / (255.5 + 82.3) = 0.7563647

R square

     R2m       R2c
[1,]   0 0.7563286

Compute ICC

Linear mixed model fit by REML ['lmerMod']
Formula: Future ~ Contribution + Culture + Contribution * Culture + (1 |  
    Dyad)
   Data: data_example

REML criterion at convergence: 142.9

Scaled residuals: 
    Min      1Q  Median      3Q     Max 
-1.5738 -0.5010  0.1035  0.3899  1.4818 

Random effects:
 Groups   Name        Variance Std.Dev.
 Dyad     (Intercept) 176.42   13.282  
 Residual              43.76    6.615  
Number of obs: 20, groups:  Dyad, 10

Fixed effects:
                     Estimate Std. Error t value
(Intercept)           71.8309     4.4696  16.071
Contribution           0.8448     0.2557   3.304
Culture               -9.0328     4.4696  -2.021
Contribution:Culture   0.4873     0.2557   1.906

Correlation of Fixed Effects:
            (Intr) Cntrbt Cultur
Contributin 0.050               
Culture     0.004  0.086        
Cntrbtn:Clt 0.086  0.587  0.050 

Compute ICC

  Future
Predictors Estimates CI p
(Intercept) 71.83 62.24 – 81.42 <0.001
Contribution 0.84 0.30 – 1.39 0.005
Culture -9.03 -18.62 – 0.55 0.063
Contribution * Culture 0.49 -0.06 – 1.04 0.077
Random Effects
σ2 43.76
τ00 Dyad 176.42
ICC 0.80
N Dyad 10
Observations 20
Marginal R2 / Conditional R2 0.468 / 0.894

How much variance is explained by the two predictors and the interaction?

1 - ((176.42 + 43.76) / (255.5 + 82.3)) = 34.8%

Actor-Partner Interdependence Model (APIM)

Actor-Partner Interdependence Model (APIM)

Actor Partner Interdependece Model

Actor-Partner Interdependence Model (APIM)

  • Pairwise data set
  • Distinguishable and indistinguishable
  • The trick for indistinguishable dyads is to constraint the parameters to be equal. It results in one actor effect and one partner effect.
  • The null model for dyadic analysis is not the all-free model. The null model should have constrained the means and variances of the actors.

Structural Equation Model Approach

Structural Equation Model Approach

Confirmatory Factor Analysis

Structural Equation Model Approach

SEM approach

Example in Mplus

  • Open dyadic.inp

  • Data are on dyadic_data.dta

  • Run

  • What is the correlation between dyads?

Aditional resources