Simulated data, validity reports and a firefighter predictive validation study are used to examine validity bias created by three common selection problems-range restriction, applicant and incumbent attrition, and nonlinearity created by compression of high selection test scores. Top 20% selection samples drawn from an applicant pool with known validity coefficients demonstrate that the sample validity estimates of the three predictors are differentially biased in both magnitude and direction, depending on the selection strategy used. Concurrent validity designs generally favor novel predictors. Corrections for direct range restriction across situations were mostly ineffectual. With proper scaling, corrections for indirect range restriction are accurate, but cross-variable biasing effects can occur when score distributions of the individual predictors differ. Many of the biases found in the simulation results are demonstrated in a firefighter predictive validation study where variations of Pearson-Thorndike range corrected validities and a full information maximum likelihood (FIML), approaches are all compared as validity assessments. With normalized predictors, both Pearson and FIML methods show that a test of general mental ability and physically demanding job tasks predicted firefighter performance throughout the 30-year study, with no evidence of interactions or a leveling of performance at high test scores.Pearson (1903) described the role of selection in altering means, variances, and correlations of variables in the selected sample, relative to the population from which the sample was drawn. He also demonstrated that altered sample variance effects differ when selection is explicit on a variable or operates indirectly on that variable. Pearson's conclusion that ". . . correlation can be created or destroyed or reversed by selection" (p. 29) was ignored by psychologists until Thorndike (1947) found that Pearson's equations explained the low predictive validity coefficients obtained in a highly selected sample of pilot applicants in WWII. Thorndike (1949) introduced the term range restriction (RR) and Pearson's equations for correcting bias in observed sample correlations, reframing Pearson's natural selection variance restriction orientation into bias correction relevant to personnel selection. Thorndike (1949) asserted:If any intelligent use be made of validity statistics from a restricted group, some statistical correction procedures are necessary to estimate what validity coefficients would have been obtained if it had been possible to obtain test and criterion data from a representative sample of all those to whom the selection devices were applied. (p. 171-172).He also concluded that indirect selection was the most common and important in personnel selection. Thorndike's treatment of range restriction and the necessity to use applicant pool referenced, not selected sample, validity coefficients, were widely accepted in textbooks (e.g., Guilford, 1956).