Forest plot of the effect sizes and their 95% confidence intervals for safer sexual behavior interventions (k = 4). The size of the square representing each effect size is proportional to its weight in the analysis; larger squares indicate a study that was weighted more heavily in the analysis. Effect sizes significantly favoring the intervention groups appear in white, effect sizes favoring neither the intervention nor control are in black (none of the effect sizes significantly favored the control condition). The line running through the effect size square represents the size of the 95% confidence interval.