Graham M. Silk-Eglit, Julie K. Lynch, Robert J. McCaffrey; Validation of Victoria Symptom Validity Test Cutoff Scores among Mild Traumatic Brain Injury Litigants Using a Known-Groups Design. Arch Clin Neuropsychol 2016; 31 (3): 231-245. doi: 10.1093/arclin/acv108
The Victoria Symptom Validity Test (VSVT) is one of the most accurate performance validity tests. Previous research has recommended several cutoffs for performance invalidity classification on the VSVT. However, only one of these studies used a known groups design and no study has investigated these cutoffs in an exclusively mild traumatic brain injury (mTBI) medico-legal sample. The current study used a known groups design to validate VSVT cutoffs among mild traumatic brain injury litigants and explored the best approach for using the multiple recommended cutoffs for this test. Cutoffs of <18 Hard items correct, <41 Total items correct, an Easy – Hard items correct difference >6, and <5 items correct on any block yielded the strongest classification accuracy. Using multiple cutoffs in conjunction reduced classification accuracy. Given convergence across studies, a cutoff of <18 Hard items correct is the most appropriate for use with mTBI litigants.