The Invariant Component Structure of the Personality Assessment Inventory (PAI) Full Scales

Abstract

We investigated methodological and sample-based characteristics that might contribute to discrepancies in the structure of the 22-scale Personality Assessment Inventory (PAI; Morey, 1991, 2007). In Study 1, we used parallel analysis, Velicer's minimum average partial procedure, and random variables to determine the appropriate number of principal components to retain in a clinical sample (N = 227). We retained 3 oblique dimensions that broadly emphasized (a) general distress, (b) elevated mood and dominance, and (c) substance abuse and psychopathy. In Study 2, we applied the same uniform criteria and procedures to 5 previously published samples and conducted orthogonal vector matrix comparisons to determine how congruent 3- and 4-dimensional structures were across samples. Results suggested the PAI has 3 dimensions that are highly congruent across samples. Using Morey's normative sample, we provide the formulas needed to compute T scores for each component so they can be used in clinical work with patients. We discuss clinical implications and directions for future PAI research.

Acknowledgments

Preliminary results were presented at the 2006 annual meeting of the Society for Personality Assessment, San Diego, California.

Editor's Note: Mark Blais served as the Editor with full decision authority over this manuscript.

Notes

^a Data for the ICN scale was unavailable

^b Alcohol Problems and Drug Problems scales were not included in analyses because of the nature of the sample

^c Based on 344 PAI items

^d Based on 160 PAI items

^e German version.

¹ The r between Negative Impression Management (NIM) and Positive Impression Management (PIM) in the clinical sample is −.45 not .45.

² The average absolute value of pattern matrix loadings for these random variables was |.09|, and the three highest loadings were |.26|, |.21|, and |.20|, respectively.

^a Percent of variance explained after oblique rotation.

³ The German PAI includes a revised ICN scale that is composed of the same number of items as the original PAI. However, it includes different items.

^a There was indeterminacy in some solutions, so values within .0006 of the minimum are provided

^b German version.

⁴ At the request of the Editor, we investigated PAI dimensional structure after excluding the INF and ICN scales. We extracted three components from the remaining 20 PAI scales, and each was highly correlated with a corresponding dimension reported in Table 2 (all rs = |.91|).