Comparison of two random-effects methods of meta-analysis.

Two studies compared the Schmidt-Hunter method of meta-analysis (J. E. Hunter & F. L. Schmidt, 1990) with the method described by L. V. Hedges and J. L. Vevea (1998). Study 1 evaluated estimates of rho, sigmarho, and resulting credibility intervals for both models through Monte Carlo methods. Results showed slight differences between the 2 methods. In Study 2, a reanalysis of published meta-analyses using both methods with several artifact distributions showed that although both choice of technique and type of correction could matter, the technique of meta-analysis used is less influential on the study outcome than is the choice of artifact correction.