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Figure 4: Galbraith plot analysis[4] For each study, ratio of the log odds ratio to its standard error (yaxis) is plotted against reciprocal of the standard error (xaxis). Thus, the least precise findings from small studies appear towards the left of the figure and results from the largest studies appear towards the right. An overall (log) odds ratio is represented by the slope of the solid line through the origin in the figure. The dotted lines are positioned two units above and below the solid line and delimit an area in which, in the absence of statistical heterogeneity, the majority (95%) of the study results would be expected to lie. Those situated above[13,16,18] and below[11,12] the dotted lines are considered outlier studies 
