Our study has four main limitations. First, the sample was drawn from insurers and involved clinical categories that are not representative of malpractice claims nationwide. Academic institutions and the physicians who staff them were overrepresented, as were claims that fell within our clinical categories of interest. Although it is difficult to make comparisons with other samples of closed claims, both the proportion of claims receiving payments and the average amount of the payments appear to be high according to national standards, which probably reflects the preponderance of severe injuries in our sample.
Second, the reliability of judgments that error had occurred was moderate overall; agreement was especially difficult to obtain among claims involving missed or delayed diagnoses. Third, whether claims had merit was determined by reference to error, which is not identical to the legal concept of negligence, although the two cleave so closely that experts in both medicine and law have trouble explaining the difference. Fourth, reviewers' awareness of the litigation outcome may have biased them toward finding errors in claims that resulted in compensation, and vice versa.35,36 To the extent that such hindsight bias was a factor, its likely effect would be to pull the rate of non-error claims (37 percent) toward the payment rate (56 percent), resulting in an overestimate of the prevalence and costs of claims not associated with error.
Frivolous litigation is in the bull's-eye of the current tort-reform efforts of state and federal legislators. The need to constrain the number and costs of frivolous lawsuits is touted as one of the primary justifications for such popular reforms as limits on attorneys' fees, caps on damages, panels for screening claims, and expert precertification requirements. Our findings suggest that moves to curb frivolous litigation, if successful, will have a relatively limited effect on the caseload and costs of litigation. The vast majority of resources go toward resolving and paying claims that involve errors. A higher-value target for reform than discouraging claims that do not belong in the system would be streamlining the processing of claims that do belong.
Supported by grants from the Agency for Healthcare Research and Quality (HS011886-03 and KO2HS11285, to Dr. Studdert), and the Harvard Risk Management Foundation. No potential conflict of interest relevant to this article was reported.
We are indebted to Allison Nagy for her assistance in compiling the data set; to Karen Lifford, Tom McElrath, and Martin November for their assistance with the obstetric component of the study; to Selwyn Rogers for his assistance with the surgical component; to Eric Thomas and Eric Poon for their assistance with the medication and diagnostic components; and to John Ayanian, Arnold Epstein, John Orav, and Charles Silver for their valuable comments on an earlier draft of the manuscript.