Aggregated Data Meta-Analysis and IPDMA Traditional meta-analyses use aggregated or summary level information from studies or reports (Cooper & Patall, 2009; Riley et al., 2010). Analysts conducting aggregated data meta-analysis would look up relevant literature and code summary statistics needed to calculate one or more effect sizes from each study and also code the corresponding moderator variables. And, then run meta-regression models to (1) summarize effect size estimates across studies, (2) characterize variability in effect sizes across studies, and (3) explain the variability in the effect sizes.