Correcting for Sampling Error: Variance Adjustments

While the sample weighted mean correlation is not affected by sampling error, its variance is greatly increased. A two stage procedure is used to correct the variance of the sample weighted mean correlation. The first stage calculates the sampling error variance:

where K is the number of studies in the analysis.

To estimate the biased population variance, uncorrected for measurement or range departure, the sampling error variance is subtracted from s²_r .