Using likelihood ratios to detect invalid performance with performance validity measures.

Larrabee (2008) applied chained likelihood ratios to selected performance validity measures (PVMs) to identify non-valid performances on neuropsychological tests. He presented a method of combining different PVMs with different sensitivities and specificities into an overall probability of non-validity. We applied his methodology to a set of 11 PVMs using a sample of 255 subjects. The results of the study show that in various combinations of two or three PVMs, a high reliability of invalidity can be determined using the chained likelihood ratio method. This study advances the ability of clinicians to chain various PVMs together and calculate the probability that a set of data is invalid.