The journal has been notified of an error in the paper entitled Simple monograms to calculate sample size in diagnostic studies (Emerg Med J 2005;22:180–1). The error occurs on the example line on the specificity nomogram (fig 1 part B). A correct version of this figure is available at http://emjonline.com/supplemental. It should be noted that the error only affects the example and not the underlying nomogram itself.