Objective: To determine the proportion of the normal population expected to have false clinical scale elevations on the Personality Assessment Inventory (PAI: Morey, 1991) due to aggregation of Type I error. Past research has established that simultaneous interpretation of multiple scales increases the likelihood of Type I error, leading to the misclassification of a portion of the normal population as pathological. Data Selection: The PAI Professional Manual (1997) provides normative data for a sample of 1,000 census matched normal adults and 1,246 clinical patients. In addition, the interscale correlation matrices for the normative sample were provided by the PAI author, Les Morey, PhD, via personal communication. Data Synthesis: Cumulative frequencies of elevated PAI scales were generated for the normal population using Monte Carlo methodology in PASW Statistics 18 (SPSS Inc., released 2009). Please see Crawford et al. (2007) for a more detailed description of Monte Carlo simulation. Frequencies were generated using interscale correlations from the standardization sample for all PAI scales combined. Analyses revealed that 28.4% of the normal population have 1 or more incorrectly elevated clinical scale due to Type I error, leading to over-interpretation of psychopathology. Conclusion: More than one in four normal adults may be miscategorized as having features of a psychological disorder. These findings are consistent with a growing literature on rates of apparently abnormal scores in the normal population due to multiple score interpretation. Clinicians should use caution in interpreting multiple scores simultaneously, make careful use of extra-test data, and set appropriate T-score cutoffs to minimize misinterpretation.
Preserving Normal: Minimizing the Risk of Pathologizing Healthy Adults when using the Personality Assessment Inventory
A Lammy, A Odland; A-44
Preserving Normal: Minimizing the Risk of Pathologizing Healthy Adults when using the Personality Assessment Inventory. Arch Clin Neuropsychol 2015; 30 (6): 502. doi: 10.1093/arclin/acv047.44
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