Figure 2:

Forest plot of all meta-analyzed studies. Each intervention comprises one point estimate; for papers with multiple interventions in one theoretical category, the plotted point corresponds to a fixed effects meta-analysis for each paper. For papers with multiple interventions reflecting different theories, each paper-theory combination is plotted on its own. Point size is inversely proportional to variance. Points are sorted within theory by estimate size. The vertical black line demarcates an effect size of zero, and the dotted line is the observed overall effect.