ESTIMATION OF SAMPLING ERROR VARIANCE IN THE METAANALYSIS OF CORRELATIONS - USE OF AVERAGE CORRELATION IN THE HOMOGENEOUS CASE

The estimate of the population correlation used in the formula for sam pling error variance of a correlation is typically the observed correl ation, but in meta-analysis the average of the observed correlations c an be used. For the case in which there is no variation in the study p opulation correlations or sample sizes and the number of studies is ve ry large, the authors found that use of the average correlation estima tor is more accurate than use of the traditional, individual correlati on estimator, except in those rare cases in which the uncorrected popu lation correlation is greater than .60. For typical sample sizes, when the uncorrected population correlation is between -.40 and .40, there is virtually no error in the meta-analysis credibility interval based on the average correlation estimator. On the other hand, the amount o f the error in the individual correlation estimator is qualitatively i mportant if the sample is 25 or less and the population correlation is less than .40.