The Use of Multiple Performance Validity Tests

Abstract

Performance validity tests (PVTs) have become an important part of the neuropsychologist's armamentarium, especially where financial gain is an issue. It has been argued that the addition of more and more PVTs to a battery strengthens the confirmation of an overall diagnosis of lack of credibility. It has been suggested that a criterion of two or more, or three or more, failed PVTs is a good predictor of a genuine lack of effort on the part of the client. However, the validity of a diagnosis of lack of performance validity depends upon the number of tests administered as well as the number of tests failed. This can be calculated by computing the binomial equation across the specific number of tests administered relative to the specific number of failed tests. This computation assumes that false-positives for a given PVT can be estimated at 10% and that most PVTs are relatively independent of one another. Although it is counter-intuitive, adding more and more PVTs does not automatically increase the likelihood of a true positive diagnosis of non-credible performance.

Keywords:

• performance validity
• multiple PVTs
• traumatic brain injury