A personal floor effect strategy to evaluate the validity of performance on memory tests

Four methods of assessing the validity of performance on a word recognition test were compared among 609 criminal defendants engaged in competency-to- stand-trial evaluations. One of the methods, the "normative" floor effect s trategy, involves comparing an individual's performance to the average perf ormance of individuals with true memory impairment. In this sample, 16.9% o f defendants performed below the normative floor for individuals with true impairment. Another method, the "personal" floor effect strategy, identifie s performance as suspect when individuals perform below a level for which t hey themselves have already demonstrated intact ability. In this sample, th e personal floor effect strategy identified fewer instances of suspicious p erformance (15.6%), but the strategy may be less sensitive to true memory i mpairment than the normative floor effect. Consequently, the personal Floor effect strategy may be more compelling as evidence of poor effort or bad i ntentions on memory testing. Convergent validity of the personal floor effe ct strategy is demonstrated over four analyses.