A robust five-factor structure of the 16PF: Strong evidence from independent rotation and confirmatory factorial invariance procedures

Establishing factorial invariance across samples and forms has important implications for efforts to build a taxonomy of personality traits. These methods provide a strong test of measurement properties and, if factorial invariance obtains, allow meaningful factor comparisons across groups. Results are presented for an invariant second-order factor structure in two forms (Form C and Clinical Analysis Questionnaire) of the 16PF and across six independent samples: four samples consisting of male and female police applicants (combined N = 15,332) and two samples of male felons (combined N = 15,460). Independently rotated common factor analyses indicated that six previously reported factors (Extraversion, Anxiety, Control, Independence, Sensitive Awareness, and Intelligence) were well-replicated in all samples. A restricted factor solution (salient loadings only) with identical factor loadings (metric factorial invariance) was found to hold remarkably well across all samples. Further constraints on the factor model known as ‘strict factorial invariance’ (Meredith, 1993; invariant factor loadings, mean intercepts, and unique variances) were found to provide a good fit to the data within police applicant and felon samples. The findings from this study offer strong evidence in support of a stable five-factor personality structure of the 16PF across different forms and people.