1. Patterns of Actor and Partner Effects
David A. Kenny

2. You need to know the Actor Partner Interdependence Model!
APIM

3. APIM Patterns: Couple Model
Equal actor and partner effects: a = p
e.g., my depressive symptoms has the same effect on my quality of life as does my partner’s depressive symptoms on my quality of life
Average or sum as the predictor
Although measured individually, the predictor variable is a “dyadic” variable, not an individual one

4. APIM Patterns: Contrast
Model
Actor plus partner effects equals zero: a – p = 0
Klumb et al. (2006): time spent doing household labor on stress levels
The more household labor I do, the more stressed I feel.
The more household labor my partner does, the less stress I feel.
Difference score (actor X minus partner X) as the predictor

5. APIM Patterns: Actor or Partner Only
Actor Only
Actor present but no partner effect
Fix the partner effect to zero.
Partner Only
Partner present but no partner effect
Fix the actor effect to zero.
Relatively rare.

6. Testing Patterns Multilevel Modeling Structural Equation Modeling
Sum and difference approach
Structural Equation Modeling
Setting coefficients equal
Use of phantom variables
General approach to patterns: k

7. Sum and Difference Approach
Remove the actor and partner variables from the model.
Add to the model the Sum and the Difference score as predictors.
If Sum is present, but not the Difference, you have a couple model.
If Sum is not present, but the Difference is, you have a contrast model.

8. Acitelli Example Distinguishable Husbands Sum: 0.392, p < .001
Difference: 0.131, p = .088
Wives
Sum: 0.373, p < .001
Difference: 0.001, p = .986
Indistinguishable
Sum: 0.344, p < .001
Difference: 0.056, p = .052

9. Testing the Couple Model Using SEM
Actor effect equal to the partner effect.
Can be done by setting paths equal.
Distinguishable dyads
a1 = p12 and a2 = p21
Indistinguishable dyads
a = p

10. Acitelli Example Distinguishable Husbands: 0.346 Wives: 0.347
Test: c2(2) = 4.491, p = .106
Indistinguishable
Effect: 0.344
Test: c2(1) = 3.803, p = .051

11. Testing the Contrast Model Using SEM
Actor effect equal to the partner effect times minus 1.
Can be done by using a phantom variable.
Phantom variable
No conceptual meaning
Forces a constraint
Latent variable
No disturbance

12. Contrast Constraint Forced by Phantom Variables (P1 and P2)X1 a1 Y1 1 E1 -1 a2 P1 a1 P2 -1 X2 Y2 1 E2 a2
Now the indirect effect from X2 to Y1, p12 equals (-1)a1

13. Acitelli Example
c2(2) = , p < .001

14. Conclusion
Using patterns can link the APIM to theory and simplify the model. The k parameter is a general way to measure and test patterns Readings pp , in Dyadic Data Analysis by Kenny, Kashy, and Cook Kenny & Cook, (1999), Personal Relationships, 6, pp