David S. Nichols

What Do the MMPI–2 Restructured Clinical Scales Reliably Measure? Answers From Multiple Research Settings

The Restructured Clinical (RC; Tellegen et al., 2003) scales were developed to improve measurement of the core constructs of the MMPI–2 (Butcher et al., 2001) Clinical scales by removing “demoralization,” hypothesized to affect these scales adversely. Using 25 samples with MMPI–2 responses from 78,159 subjects across diverse clinical settings, we found that each RC scale was highly correlated with a Supplementary, Content, or Personality Psychopathology 5 (PSY–5; Harkness, McNulty, & Ben-Porath, 1995) scale: higher, in fact, than the correlation between the RC scale and its parent scale. Furthermore, for over half the RC scales (i.e., RC1, RC3, RC7, RC8, and RCd), the correlations were strong enough to conclude that the RC scales replicate MMPI–2 scales with rich empirical foundations; the remaining RC scales were not redundant. Next, we examined reliability estimates using alpha coefficients and interitem correlations and did not reveal superior reliability for most of the RC scales over existing MMPI–2 scales.

The MMPI–2 Restructured Clinical (RC) Scales and Redundancy: Response to Tellegen, Ben-Porath, and Sellbom

In this article, we examine 5 criticisms of Tellegen, Ben-Porath, and Sellbom (2009/this issue) about our study demonstrating the redundant relationships of the Restructured Clinical (RC) scales with extant MMPI–2 scales. We discuss differences in univariate versus multivariate comparisons of the RC scales and our “proxy” scales using their data. We show that (a) both the RC and extant proxy scales identified in our analyses account for most of the variance in the Clinical scales; (b) the proxy scales are redundant with the RC scales; (c) the proxy scales matched the 6 RC scales in accounting for variance in the Clinical scales exactly in three cases, differed by ≤.02 in 2 cases, and reached a maximum of .11 in one case; (d) the item overlap between RC1 and HEA is not at issue but rather their correlation with Scale 1; and (e) the evidence for the construct validity of the RC scales is weak using findings on the incremental validity of RC4 as illustrative.

Construct drift in the MMPI‐2 restructured clinical scales: further evidence and a possible historic example

Construct drift (Nichols, 2006) describes the possibility that the MMPI-2 Reconstructed Clinical (RC) scales are less accurate measures of the primary traits than the original Clinical scales. The authors review the development of RC scales RC4, RC7, and RC9 and provide further evidence that these scales measure traits and behaviors that are not necessarily equivalent to those assessed by the original scales. Further, the development of the original Clinical Scale 7 is reviewed and evidence is provided that suggests that construct drift is not a new phenomenon, but may have been present in the development of the original scales. Suggestions for future research as well as cautions with regard to the clinical interpretation of the RC scales are provided.