The ecological validity of the IOP-29: A follow-up study using the MMPI-2-RF and the SIMS as criterion variables

Current guidelines for conducting symptom validity assessments require that professionals administer multiple symptom validity tests (SVTs) and that the SVTs selected for their evaluations provide nonredundant information. However, not many SVTs are currently available, and most of them rely on the same, (in)frequency-based, feigning detection strategy. In this context, the Inventory of Problems (IOP-29) could be a valuable addition to the assessor's toolbox because of its brevity (29 items) and its different approach to assessing the credibility of presented symptoms. As its ecological validity has been poorly investigated, the present study used a criterion groups design to examine the classification accuracy of the IOP-29 in a data set of 174 court-ordered psychological evaluations focused on psychological injury. The validity scales of the Minnesota Multiphasic Personality Inventory-2 Restructured Form and the total score of the Structured Inventory of Malingered Symptoms were used as criterion variables. Overall, the results of this study confirm that the IOP-29 is an effective measure (1.70 ≤ d ≤ 2.67) that provides valuable information when added to the multimethod assessment of symptom validity in civil forensic contexts. (PsycInfo Database Record (c) 2023 APA, all rights reserved).