Extending Validity Evidence for the MMPI-3: The Role of Collateral Report in Adult Assessment.

Integration of multiple data sources is central to evidence-based clinical psychological assessment. In adult assessments (in contrast to youth), data are typically obtained solely from clients; however, extant research suggests collateral ratings provide valuable additional information across the lifespan. The current study examined criterion-related and incremental validity of collateral-report via the ASEBA Adult Behavior Checklist (ABCL) in association with MMPI-3 Restructured Clinical and select Specific Problems Scales. We expected 1) modest correspondence between MMPI-3 scales and corresponding ABCL scales, consistent with meta-analytic findings on self*collateral correlations (e.g., Achenbach et al., 2005); and 2) collateral-report to significantly increment variance accounted for by self-report in predicting congruent MMPI-3 scales. The sample included 107 undergraduate students (61.8% White) who completed self-report measures and recruited a collateral reporter (mostly friends/roommates). Correlations between hypothesized MMPI-3 and ABCL scales ranged from -0.00 (ABCL Intrusive-MMPI-3 Activation) to .43 (ABCL Anxious-Depressed-MMPI-3 Demoralization). Incremental validity of collateral-report (small-medium effects) was demonstrated in seven of 12 models (58.3%). Findings indicate correspondence between ABCL collateral-report and congruent MMPI-3 scales is modest and variable and extend the criterion-related validity evidence available for the MMPI-3. Results are consistent with extant literature arguing that collateral-report provides unique incremental information, reaffirming the utility of multi-informant data in the adult assessment context.