Departures from linearity as evidence of applicant distortion on personality tests

Two field studies were conducted to examine how applicant faking impacts the normally linear construct relationships of personality tests using segmented regression and by partitioning samples to evaluate effects on validity across different ranges of test scores. Study 1 investigated validity decay across score ranges of applicants to a state police academy (N = 442). Personality test scores had nonlinear construct relations in the applicant sample, with scores from the top of the distribution being worse predictors of subsequent performance but more strongly related to social desirability scores; this pattern was not found for the partitioned scores of a cognitive test. Study 2 compared the relationship between personality test scores and job performance ratings of applicants (n = 97) to those of incumbents (n = 318) in a customer service job. Departures from linearity were observed in the applicant but not in the incumbent sample. Effects of applicant distortion on the validity of personality tests are especially concerning when validity decay increases toward the top of the distribution of test scores. Observing slope differences across ranges of applicant personality test scores can be an important tool in selection.