To the Editor. —I found the decision rules described by Stiell et al 1 potentially very useful. However, it is difficult to assess their true value because some potentially important information was not included in the article. The abstract states that the decision rules had sensitivities of 1.0 for ankle and foot fractures. However, it is apparent from the body of the article and from Tables 1 and 5 that these sensitivities are actually based on the ability of the rules to predict what the authors consider "clinically significant" fractures. It would be very helpful to know how the authors define clinical significance, as well as how sensitive the rules were for detecting the 31 clinically insignificant fractures.