Validity testing and beyond: Identifying and managing extraneous factors impacting interpretation of neuropsychological measures

Assessment of test validity is now a standard component of neuropsychological assessment. However, within a clinical, nonforensic setting, patients without clear incentive for intentional underperformance or exaggeration sometimes fall within established ranges for invalidity on validity test measures, resulting in interpretative challenges. This paper aims to provide an overview of the use of validity testing (VT) in the assessment of both intentional feigning of impairment and inadequate test engagement, factors that may impact both VT and neuropsychological test performance, and methods for promoting maximal engagement and effort during clinical evaluations. We discuss the evolution of VT in clinical neuropsychology documented in the literature as well as research addressing the impact of extraneous factors that may result in diminished test performances in a clinical context. We suggest strategies for managing some of these extraneous factors in terms of their impact on the overall evaluation, diagnostic formulation, and treatment planning. We include anecdotal examples in which validity testing may not be feasible or necessary, though with the understanding that our field has endorsed consensus statements on the use of VT in general. These consensus statements emphasize the necessity of routinely evaluating test validity, yet they also underscore the importance of interpreting findings within the broader clinical context. Within a clinical setting, neuropsychologists are equipped to interpret test data within the total context of the case and maximize patients' engagement to improve the degree of test validity in each evaluation.