Experiments in Daily Life: When Causal Within-Person Effects Do (Not) Translate Into Between-Person Differences

Abstract

Intensive longitudinal designs allow researchers to study the dynamics of psychological processes in daily life. Yet, because these methods are usually observational, they do not allow strong causal inferences. A promising solution is to incorporate (micro-)randomized interventions within intensive longitudinal designs to uncover within-person (Wp) causal effects. However, it remains unclear whether (or how) the resulting Wp causal effects translate into between-person (Bp) differences in outcomes. In this work, we show analytically and using simulated data that Wp causal effects translate into Bp differences if there are no counteracting forces that modulate this cross-level translation. Th..