Limited English Proficiency Increases Failure Rates on Performance Validity Tests with High Verbal Mediation

This study was designed to examine the effect of language proficiency and level of verbal mediation on failure rates on performance validity tests (PVTs). PVTs with high and low verbal mediation were administered to 80 healthy community-dwelling English-Arabic bilinguals. Digit Span and Animal Fluency were administered in both English and Arabic, in counterbalanced order, as part of a brief battery of neuropsychological tests. Participants with Arabic as their dominant language were 2 to 16 times more likely to fail PVTs with high verbal mediation compared to native speakers of English. When Digit Span and Animal Fluency were administered in the nondominant language, participants were 2 to 18 times more likely to fail the validity cutoffs. Language dominance explained between 6 and 31% of variance in dichotomized outcomes (pass/fail) on PVTs with high verbal mediation. None of the participants failed any PVTs with low verbal mediation. Limited language proficiency may result in dramatic increases in false positive rates on PVTs with high verbal mediation. Failure on a PVT administered in English to an examinee with a different linguistic background should be interpreted with great caution.