to bias when different studies measure different outcomes (e.g., Raudenbush et al., 1988). Because we are aware of no appropriate method to test the within-study moderation effects hypothesized by the DM, we estimated effect sizes for group differences in sedation and simulation (and on the ascending and descending limbs) separately. We therefore estimated eight distinct effects to compare the LLRM and DM: group differences in sedation and stimulation, group differences on the ascending and descending limbs, and group differences in sedation and stimulation within each limb.
