Performance validity test failure predicts suppression of neuropsychological test results in developmentally disabled children.

There is increasing awareness of the need to use Performance Validity Tests (PVTs) when assessing cognitive abilities in children. Since 1996, there has been an ongoing clinical study of the use of three PVTs with a consecutive series of 1,285 developmentally disabled children. In this study, we report on the results of these PVTs in children of many diagnostic categories. Failure rates on all three tests were very low. The mean scores on the effort measures in those passing the PVTs were extremely high. Failure on each PVT was found to be associated with a significant and widespread suppression of scores across a neuropsychological battery. Failure on even one PVT significantly suppresses ability test scores.