Advancing the Longitudinal Measurement of Physical Aggression from Age 3 to 15: Applications of Moderated Non-Linear Factor Analysis.

Physically aggressive behavior among children and adolescents is a longstanding concern, as documented in a large body of literature examining trajectories of aggressive behavior. However, aggression has been shown to present differently across the life course and is also likely to present differently across population subgroups, complexity that challenges the understanding and prevention of, and intervention in, problem behaviors. We therefore created covariate-informed trajectories of aggressive behaviors and identified subgroups representing heterogeneity in the development of girls' and boys' physically aggressive behaviors from ages 3 to 15 years. We used data from 3,263 families in the Future of Families and Child Well-being Study (waves 3-6, ages 3-15 years), a longitudinal birth cohort study following children born in large cities between 1998 and 2000 to mostly unmarried mothers. We used moderated non-linear factor analysis to generate factor scores of physically aggressive behaviors over time, separately for boys and girls, and then ran sex-separated latent growth models using the covariate-informed factor scores. Both girls and boys had three-class change trajectories. For adolescent girls, there is just one trajectory toward physically aggressive behavior (with the third classification as Desistors). For adolescent boys, there are two trajectories toward aggressive behavior (including Adolescent Onset). While universal programming that is not gender-responsive can meet the needs of young people who were classified as Persistors or in the Low Aggression group, we observed unique possible points of intervention and sex-specific needs. In response, we advise on interventions for young people, adults in youth-serving organizations, and structural-level considerations.