The authors attempt to address the concern that the estimates of deaths related to medical errors are overestimates, which do not account for the expected risk of death in the absence of medical error. The authors retrospectively reviewed medical records of in-hospital deaths. A panel of internists analyzed these cases with an implicit review tool, estimating whether deaths could have been prevented by optimal care and determining the probability patients would have lived to discharge or for more than 3 months. The reviewers found almost one fourth of patient deaths (22.7%) were rated as at least possibly preventable by optimal care, with 6.0% rated as probably or definitely preventable. In their analysis, the authors report that clinicians estimated that only 0.5% of patients who died would have lived 3 months or more in good cognitive health if care had been optimal. They conclude that previous reports of deaths related to medical errors may be overestimated.