Fig. 5

Orchard plots per cluster with non-absolute data, indicating that in all clusters the effects are considered non-distinguishable from zero and statistically non-significant. Besides, heterogeneity is assumed to be present in all clusters. This is reflected by the estimate (open circle), the confidence interval (horizontal thick black line), and the prediction interval (horizontal thin line). The number of effect sizes is represented by k and the number of data sets is between parentheses. The size of the color filled circles corresponds with the precision of the effect size