Can faking be measured with dedicated validity scales? Within-Subject Trifactor Mixture Modeling applied to BIDR responses

A sample of 516 participants responded to the Balanced Inventory of Desirable Responding (BIDR) under answer honest and instructed faking conditions in a within-subjects design. We analyse these data with a novel application of trifactor modeling that models the two substantive factors measured by the BIDR – Self-Deceptive Enhancement (SDE) and Impression Management (IM), condition-related common factors and item specific factors. The model permits examination of invariance and change within subjects across conditions. Participants were able to significantly increase their SDE and IM in the instructed faking condition relative to the honest response condition. Mixture modeling confirmed the existence of a theoretical two-class solution comprised of approximately two thirds of ‘compliers’ and one third of ‘non-compliers’. Factor scores had good determinacy and correlations with observed scores were near unity for continuous scoring, supporting observed score interpretations of BIDR scales in high stakes settings. Correlations were somewhat lower for the dichotomous scoring protocol. Overall, results show that the BIDR scales function similarly as measures of socially desirable functioning in low and high stakes conditions. We discuss conditions under which we expect these results will and will not generalise to other validity scales.