Validity of Informant Report Interpretations: Role of Examinee Performance and Symptom Invalidity

Performance validity tests (PVTs) and symptom validity tests (SVTs) detect inaccuracies in examinee-completed measures, though methods for assessing the accuracy of informant reports-which may be inaccurate due to examinee deception, motivation for external incentives (e.g., disability payments), or attempts to validate examinee experiences-remain underexplored. We used a sample of 72 veteran-informant dyads undergoing evaluation of possible epilepsy-related neurocognitive disorder to assess the association between examinee response invalidity (i.e., performance and/or symptom invalidity) and informant report measures. Examinees completed PVTs, SVTs, cognitive, and self-report measures. Informants completed measures on examinee functioning and their own caregiver burden. Performance invalidity was defined as failure on two or more PVTs. Symptom invalidity for psychopathology symptom reports (SVT-P) and cognitive/somatic symptom reports (SVT-CS) were separately defined via above-threshold scores on two or more SVT criterion. Independent samples t tests demonstrated the associations of the PVT, SVT-CS, and SVT-P groups with informant-report measures. Informants for examinees with performance invalidity reported worse functioning in the examinee than informants for examinees in the valid performance group (medium-large effect sizes). Symptom validity status (for both SVT-CS and SVT-P) was meaningfully but less strongly related to informant-reported examinee functioning (small-medium effect sizes). Neither performance nor symptom invalidity was meaningfully related to informant-reported caregiver burden (negligible effect sizes). Informant reports for examinees with response invalidity should be interpreted with caution. Public Significance Statement To ensure the public competent neuropsychological services, informant report measures should also be interpreted cautiously when examinees exhibit inaccurate test scores.