Certain limitations must be considered in interpreting the findings of our study and the value of its methodology for research on other domains of patient safety. Malpractice claims and reports are an imperfect representation of the true incidence and nature of any complication. 13-15 Some cases of retained foreign bodies undoubtedly did not result in either a claim by a patient or a report by the physician to the insurer. The factors involved in such cases may differ from those in the cases we studied. However, we know of no reason why they would differ in terms of the mechanism of causation. In addition, these mishaps appear to have a high likelihood of leading to litigation, given how injurious and potentially avoidable they are.