Correcting for indirect range restriction in meta-analysis: testing a new meta-analytic procedure.

Using computer simulation, the authors assessed the accuracy of J. E. Hunter, F. L. Schmidt, and H. Le's (2006) procedure for correcting for indirect range restriction, the most common type of range restriction, in comparison with the conventional practice of applying the Thorndike Case II correction for direct range restriction. Hunter et al.'s procedure produced more accurate estimates of both the mean and standard deviation in meta-analysis than the conventional procedure. Even when its key assumption that the effect of selection on a 3rd variable is fully mediated by the independent variable was violated, Hunter et al.'s procedure was still relatively more accurate than the conventional procedure. When applied to data from a previously published meta-analysis, the new procedure yielded results that led to different substantive conclusions.