White RE, Trbovich PL, Easty AC, et al. Checking it twice: an evaluation of checklists for detecting medication errors at the bedside using a chemotherapy model. Qual Saf Health Care 2010;19:562–7.

There are two errors in the results section of this article. The authors state that “the new checklist helped nurses to detect more errors of any type (55%; 71/130) than the old checklist (38%; 49/130)”. These fractions should not have been included because they are not a logical statistic to report. There were different numbers of planted errors in each category, making the sum of total errors unbalanced: error types which happened to have more planted errors get more weight in the fraction than those with fewer errors. The percentages reported are accurate because the authors took the average error detection percentage across each of the four types- giving them equal weight.

The authors also state that 51/60 errors in pump programming were detected with the old checklist, when it should read 54/60. The percentage value reported was correct (90%).