Desir- able processes of care (except for use of the IMA) and morbidity rates were not associated with volume. The average STS-CABG composite score for the lowest-volume group ( 100 cases per year) was significantly lower than that of the 2 highest-volume groups, but volume explained only 1% of variation in the composite score.619,790 In general, the best results are achieved most consistently by high-volume surgeons in high-volume hospitals and the worst results by low-volume surgeons in low-volume hospi- tals.793,794 However, many low-volume programs achieve excellent results, perhaps related to appropriate case selec- tion; effective teamwork among surgeons, nurses, anesthesi- ologists, perfusionists, and physician assistants; and adoption of best practices derived from larger programs.833,834 As a quality assessment strategy, participation in a state, regional, or national clinical data registry that provides regular performance feedback reports is highly recommended for all cardiac programs. Random sampling variation is greater at low volumes,309,797,798,803,827,834,835 which compli- cates performance assessment of smaller programs. 