Idiographic personality networks: Stability, variability and when they become problematic

Idiographic personality networks are gaining popularity for modeling individual differences, but their validity requires stability, which seems contradicted by theory and empirics. This study employs conventional idiographic network analysis to evaluate inter- and intra-individual variation in youngsters with a mild intellectual disability (N = 26; M_age = 23) who completed 60 daily self-reports. Results show high between-person heterogeneity in network structures, even within subgroups with a similar personality profile. Repeatedly estimating idiographic networks in a sliding 30-day window revealed within-person network variability throughout the 60 days. Both theory and our study suggest non-stationarity, which invalidates aggregated network estimates. This is problematic because capturing individuals’ stable personality networks is required to subsequently assess individual differences. We discuss implications for modeling and theory building.