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501.6
Interaction Effects in Nonlinear Models - Testing and Interpreting Core Assumptions of Situational Action Theory

However, several scholars have engaged in a discussion whether the model-inherent interaction has a meaningful interpretation. While some scholars argue that substantive interest is only on the interaction that arises from the product term variable and advocate removing the model-induced interaction from the total interaction effect (e.g. Bowen 2012), others adhere to the interpretation of the total effect (e.g. Ai & Norton 2003). So far, the discussion concerning the idea and interpretation of interaction in nonlinear models didn’t result in a common perspective.

To date, there is a lack of a systematically derived justification for one of the options, based on the combination of theoretical and methodological arguments. In order to overcome this shortcoming, we (1) develop a general perspective on the idea and meaning of interaction in nonlinear models, (2) target at developing an application scheme guiding researchers to the appropriate concept of interaction―either including the model-inherent interaction or separating it from the total interaction effect―, and (3) propose statistical tests that allow for an analysis of the interaction effect.

Situational Action Theory, a recently proposed and promising criminological theory (Wikström 2006, Wikström et al. 2012), will serve as theoretical exemplification.