Partner effects in relationship research: Conceptual issues, analytic difficulties, and illustrations

This article discusses the conceptual meaning of partner effects, which occur when one person is affected by the behavior or characteristics of his or her partner. We show that partner effects can be used to validate the presence of a relationship and can elaborate the particular nature of that relationship. We discuss possible moderation of partner effects and show that many theoretical variables in relationship research (e.g., similarity) can be viewed as the interactions of partner effects with other variables. We present three extended examples that illustrate the importance of partner effects.