Meta-analytic research is an effective method for synthesizing existing research and for informing practice and policy. Hattie (2009) suggested that meta-analytic procedures could be employed to existing meta-analyses to create a mega-analysis. The current mega-analysis examined a sample of 47 meta-analyses according to the "School Psychology: A Blueprint for Training and Practice III domains" (Ysseldyke et al., 2006), tiered level of support, and grade level. Findings support the effectiveness of school psychology services across the Blueprint domains, tiered levels of support, and grade level. However, the effect size was smallest for systems interventions (median d = 0.15), and there was limited research regarding the effect of assessment data on student outcomes.