A summary of the OR distributions for rare and common variants from a wide range of recent publications is shown in Figure 2 (see Supplementary Note online). The difference between the two distributions is quite striking. For common variants, relatively few have values above 2, and the mean OR is 1.36. For the rare variants, on the basis of a smaller set of observations but with many for which the OR could not be assessed because the variant was not observed in the controls, most have ORs above 2, and the mean OR is 3.74.
