Escalating professional liability costs prompted this study on the nature of adverse outcomes related to medical care. Findings showed that incident rates were low, but also that risks were a part of medical care, and not all of them were associated with legal fault. In addition, the resulting work provided an initial set of classifications, nomenclature, and evaluation techniques that were seen by the authors to assist in creating a more efficient patient compensation program. (A summary of the report was published as Mills DH. Medical insurance feasibility study. A technical summary. West J Med. 1978;128:360-365.)