Fig. 4

Funnel plot for the OS meta-analysis of HOTAIR. The meta-analysis for HOTAIR was analyzed with a funnel plot because it exceeded the pre-requisite of 10 studies. The Y-axis represents the Standard Error (SE), which serves as a measure of precision, where the higher the SE, the less precise the study. The HR has been plotted along the X-axis. The black dots map the effect size of HOTAIR on OS as this has been identified by each study. The light grey and dark grey areas respectively denote the 95 % and 99 % CI around the summary effect size. According to this plot, it is clear that the least precise studies tend to overestimate the effect size of HOTAIR on OS, skewing the summary effect size to the right (i.e. leading to a more strongly positive summary effect size)