Cohen's d Corrected for Case IV Range Restriction: A More Accurate Procedure for Evaluating Subgroup Differences in Organizational Research
针对组织研究中用现有员工样本估计求职者群体子群体差异时，科恩d值因范围限制而偏小的问题，提出了第四类校正方法（d_c4），并通过模拟和实际数据验证其准确性。
Organizational and staffing researchers are often interested in evaluating whether subgroup differences exist (e.g., between Caucasian and African‐American individuals) on predictors of job performance. To investigate subgroup differences, researchers often will collect data from current employees to make inferences about subgroup differences among job applicants. However, the magnitude of subgroup differences (i.e., Cohen's d ) within incumbent samples may be different (i.e., smaller) than the magnitude of subgroup differences in applicant samples because selection of applicants typically reduces the variance of scores on the predictors (i.e., because lower scoring applicants are not selected). If researchers seek to generalize a d value in an incumbent sample to the applicant population, they may use Bobko, Roth, and Bobko's (correcting the effect size of d for range restriction and unreliability, 2001) Case II or III correction. By extension, Hunter, Schmidt, and Le (implications of direct and indirect range restriction for meta‐analysis methods and findings, 2006) have proposed a Case IV correction, which is more realistic than Bobko et al.'s approach. Therefore, this paper develops a Case IV correction for d (i.e., d c4 ). The simulation results showed that the d c4 was generally accurate across 6,000 simulation conditions. Moreover, 2 published datasets were reanalyzed to show the influence of the Case IV correction on d . In addition, implications and future directions of the d c4 are discussed.