A Forest plot of the study by Kasperaviciute and colleagues, demonstrating the risk found in various subcohorts alongside the confidence interval. Cohorts are ordered by size of the cohort and the size of the rectangle indicates the size of the cohort. The diamond symbol indicates the result of the meta-analysis. This Forest plot indicates quite nicely how smaller cohorts may sometimes have seemingly counterintuitive results as in the case of the Italian cohort that has an opposite association signal. However, the size of the cohort was relatively small and therefore, the confidence interval was quite large, safely covering the overall, final association signal. The Forest plot is from the publication by Kasperaviciute and colleagues, which was published under a Creative Commons licence.
Child Neurology Fellow and epilepsy genetics researcher at the Children’s Hospital of Philadelphia (CHOP), USA and Department of Neuropediatrics, Kiel, Germany