The Actor–Partner Interdependence Model for Longitudinal Dyadic Data: An Implementation in the SEM Framework

Abstract

In dyadic research, the actor–partner interdependence model (APIM) is widely used to model the effect of a predictor measured across dyad members on one’s own and one’s partner outcome. When such dyadic data are measured repeatedly over time, both the non-independence within couples and the non-independence over time need to be accounted for. In this paper, we present a longitudinal extension of the APIM, the L-APIM, that allows for both stable and time-varying sources of non-independence. Its implementation is readily available in multilevel software, such as proc mixed in SAS, but is lacking in the structural equation modeling (SEM) framework. We tackle the computational challenges associated with its SEM-implementation and propose a user-friendly free application for the L-APIM, which can be found at http://fgisteli.shinyapps.io/Shiny_LDD. As an illustration, we explore the actor and partner effects of positive relationship feelings on next day’s intimacy using 3-week diary data of 66 heterosexual couples.

Keywords:

• longitudinal actor–partner interdependence model
• longitudinal dyadic data
• multilevel modeling
• structural equation modeling

Acknowledgments

The authors would like to thank Prof. Dr. M. Dewitte for the permission to use the LDD on sexual behavior in Flanders as motivating example in this article and as illustrative example in the online application.

Additional information

Funding

This research was supported by a grant of the Ghent University Special Research Fund, grant number BOF.STA.2015.0008.01.