“…Hence, multiple dependent effect sizes were summarized according to the method proposed by Rosenthal and Rubin [23], which uses the intercorrelations between multiple dependent outcomes to compute a more precise estimate of a pooled effect size for multiple dependent variables. Intercorrelations for QoL instruments were derived from published literature [24,25,26,27,28,29,30,31,32]. If no such intercorrelations could be derived from the literature, the mean of the dependent effect sizes was computed.…”