Assessment of standardized ethnic group differences (d) on predictors of job performance has become an important issue for applied psychologists. A number of studies have used an experimental design in which the predictor of interest was administered after an initial screening predictor. We examined the influence of prior selection on a first predictor on observed ds for second predictors in multiple-hurdle selection systems. Results of a Monte Carlo simulation indicate observed dson the second predictor are underestimated in the presence of prior selection on another predictor. More important, “downward bias” in observed standardized ethnic group difference is substantial (30-70%) when selection ratios are low, standardized ethnic group differences on the screening predictor are high, and when the first and second predictors correlate above .30. Researchers should consider the influence of range restriction in designing studies of ethnic group differences and comparing ds across predictors, particularly when data are collected under a multiple-hurdle design.