Correlates of Person Fit and Effect of Person Fit on Test Validity

Abstract

Person-fit indices ( lz and multitest lzm) derived from item response theory and used to identify misfitting examinees were computed based on responses to cognitive ability and personality tests. lz indices from different ability domains within the cognitive tests were uncorrelated with each other; lz indices from different tests within the personality domain were moderately intercorrelated. Cross-domain correlations were near 0. Test-taking motivation and conscientiousness were correlated moderately with multitest lzm for personality tests and to a lesser extent for cognitive tests. Test reactions were uncorrelated with any of the lz measures. Males had higher mean lz s than females. This difference could be partly attributed to differences in conscientiousness. African-Americans had higher mean lz than Whites. This effect could not be accounted for by test-taking motivation or conscientiousness. High values of lz affected the criterion-related validity of the set of cognitive tests such that the validity estimate decreased as lz increased.