Previous studies relating incidents of negligent medical care to malpractice lawsuits were based on data collected during a volatile period in malpractice legislation (1984) from two of the most populous states (New York and California). To see if those studies would be generalizable, the authors performed an analysis that linked medical malpractice claims data from Utah and Colorado in 1992 with clinical data from a review of almost 15,000 medical records. They found that the poor correlation between medical negligence and malpractice claims that was present in New York is also present in Utah and Colorado. Paradoxically, the incidence of negligent adverse events exceeds the incidence of malpractice, but when a physician is sued there is a high probability that it will be for rendering nonnegligent care. The elderly and the poor are particularly likely to be among those who suffer negligence and do not sue, perhaps because their socioeconomic status inhibits opportunities to secure legal representation.