The role of common method variance in MMPI-2-RF response option augmentation.

Abstract

Several studies have shown that response option augmentation (ROA), or increasing the number of response options of the Minnesota Multiphasic Personality Inventory (MMPI)-2-RF, improves the reliability of scale scores but does not improve convergent validity. However, these studies have not taken into account the response format of criterion measures, which may represent a form of common method variance (CMV). This study examined ROA with the MMPI-2-RF to determine whether number of response options is a source of CMV that may have affected previous estimates of convergent validity. The study used a repeated measures design with self-report and informant-report measures to examine differences between reliability and validity on scores from ROA and standard dichotomous MMPI-2-RF RC scales. Results replicate those of previous studies, suggesting that ROA with the MMPI-2-RF leads to small increases in internal consistency, but near-zero gains in convergent validity. Results are unable to support the proposition that CMV, due either to respondent or number of response options, meaningfully inflates correlations between measures with identical number of response options. These results consistently showing no meaningful increase in convergent validity across several studies may have implications for test authors deciding on the number of response options. Limitations and future directions are also discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).