Validation of the Hungarian FAD-GF and BAFFS in a Multi-Informant Clinical Sample of Families of Adolescents

Family functioning is central to youth adaptation, yet brief measures require validation across informants and clinical contexts. This study evaluated the Hungarian 12-item Family Assessment Device–General Functioning Scale (FAD-GF) and the three-item Brief Assessment of Family Functioning Scale (BAFFS) in 562 respondents from 213 families of adolescents with autism spectrum disorder (ASD), anorexia nervosa (AN), or diabetes mellitus (DM). Analyses included cluster-adjusted ordinal confirmatory and multigroup CFA, exploratory factor and general-factor analyses, internal-consistency estimation, and cluster-robust external-association tests. Prespecified FAD-GF models showed inadequate fit, but exploratory analyses indicated a dominant general factor accompanied by recurring local dependencies. An exploratory one-factor model with seven simultaneously estimated residual covariances showed broadly acceptable fit (CFI = 0.962, TLI = 0.946, RMSEA = 0.078, SRMR = 0.034). Internal consistency was high for the FAD-GF (α = 0.893, ωT = 0.896) and acceptable for the BAFFS (α = 0.747, ωT = 0.756). The FAD-GF supported partial scalar invariance across parents and adolescents, strict invariance across fathers and mothers, and scalar but not strict invariance across ASD and AN parents. The BAFFS supported scalar but not strict invariance across fathers and mothers and metric but not scalar invariance across ASD and AN parents; adolescent-group solutions were inadmissible, and its just-identified CFA could not test unidimensionality. Both scales showed expected associations with stress, well-being, relationship satisfaction, and coping. The findings support use of the FAD-GF total score, whereas the BAFFS is better retained as a brief observed index, particularly in parental reports, pending further cross-group validation.