A procedure for combining sample correlation coefficients and vote counts to obtain an estimate and a confidence interval for the population correlation coefficient.

Missing effect-size estimates pose a particularly difficult problem in meta-analysis. Rather than discarding studies with missing effect-size estimates or setting missing effect-size estimates equal to 0, the meta-analyst can supplement effect-size procedures with vote-counting procedures if the studies report the direction of results or the statistical significance of results. By combining effect-size and vote-counting procedures, the meta-analyst can obtain a less biased estimate of the population effect size and a narrower confidence interval for the population effect size. This article describes 3 vote-counting procedures for estimating the population correlation coefficient in studies with missing sample correlations. Easy-to-use tables, based on equal sample sizes, are presented for the 3 procedures. More complicated vote-counting procedures also are given for unequal sample sizes.