Natural frequencies improved diagnostic inference among medical students i Sweden

The ability to draw statistical inferences from test results may be generally limited among physicians. A new way of presenting statistics, called natural frequencies, has been shown to improve this ability. The current study is the first to investigate this effect in Sweden, involving senior medical students. An intra-individual cross-over design was used in which participants answered a statistical inference task presented with natural frequencies and another with percentages, which has been the customary format. A total of 74% made a correct inference on the natural frequencies task, as compared to 54% on the percentages task, with an odds ratio of 3.2, p = 0.002, 95% CI 1.52-6.81. The findings indicate that the effect of using natural frequencies arises also in a Swedish context.