Figure 1.

Cluster-level spillover effects. On the x-axis, the cluster-level spillover effect is shown as the % change in outcome among the untreated in the treated cluster from the mean in the control group [i.e., (1-RR) x 100%, where RR is the relative risk]. Outcomes were recoded so that a greater value of the spillover effect indicates an improvement in health (e.g., higher vaccination coverage, lower mortality) and a smaller value indicates poorer health (e.g., lower vaccination coverage, higher mortality). This figure excludes studies of low or very low quality and studies that did not report information that allowed for standardization. Statistical significance was determined based on the measures presented in the paper for the parameter on its original scale. (a) Information required to convert standard errors for risk differences to standard errors for (1-RR) x 100% was not reported, thus 95% confidence intervals are not presented. (b) These studies were conducted in the same country (India) and are subject to dependence.