Quantitative analysis of medical liability’s influence on medical practice is a small but growing field. The three foregoing articles illustrate three of the possible analytic approaches: case study of technological diffusion, survey of physician responses to detailed clinical scenarios, and multivariate analysis of the relation of physicians’ scenario responses to objective liability experience. The articles also offer a good picture of the state of the art: Many difficulties hamper research in this area, and these articles, like others, offer considerable illumination but leave much uncovered. Defensive medicine surely exists, but its effects on health care spending and access are unclear. The most important lessons for public policy are that tort reform may be necessary but not sufficient to reduce the problems associated with defensive medicine, and that the major malpractice problem continues to be malpractice.