Correction

In part 2 of the series “Tips for learners of evidence-based medicine”¹ the information in Fig. 1 did not fully correspond with the information provided in the text. Specifically, the data for hypothetical trial 2 in Fig. 1B should have been centred at 5% absolute risk reduction, as described in the text; instead, the figure showed trial 2 as being centred at about 6.5% absolute risk reduction. The corrected figure is presented here.

Fig. 1: Results of 4 hypothetical trials. For the medical condition under investigation, an absolute risk reduction of 1% (double vertical rule) is the smallest benefit that patients would consider important enough to warrant undergoing treatment. In each case, the uppermost point of the bell curve is the observed treatment effect (the point estimate), and the tails of the bell curve represent the boundaries of the 95% confidence interval. See the text¹ for further explanation.