The direction of effects between parenting and adolescent affective well-being in everyday life is family specific.

Numerous theories and empirical studies have suggested that parents and their adolescent children reciprocally influence each other. As most studies have focused on group-level patterns, however, it remained unclear whether this was true for every family. To investigate potential heterogeneity in directionality, we applied a novel idiographic approach to examine the effects between parenting and adolescent well-being in each family separately. For 100 days, 159 Dutch adolescents (M = 13.31, 62% female) reported on affective well-being and four parenting dimensions. The family-specific effects of pre-registered ( https://osf.io/7n2jx/ ) dynamic structural equation models indeed revealed that a reciprocal day-to-day association between parenting and adolescent affective well-being was present only in some families, with the proportion of families displaying a reciprocal association varying across the four parenting dimensions (11-55%). In other families, either parenting predicted the adolescent's affective well-being (8-43%) or vice versa (10-27%), or no day-to-day associations were found (16-60%). Adolescents with higher trait levels of environmental sensitivity and neuroticism were more strongly affected by parenting. Thus, findings suggest that the ways in which parents and adolescents influence each other in everyday life are unique, stressing the need to move towards an idiographic parenting science.