The empirical relation between surgical volume and mortality. N Engl J Med. 1979;301:1364 9. 808. Halm EA, Lee C, Chassin MR. Is volume related to outcome in health care? A systematic review and methodologic critique of the literature. Ann Intern Med. 2002;137:511 20. 809. Hughes CM. influence of hospital volume on mortality following major cancer surgery. JAMA. 1999;281:1375. 810. Hughes RG, Hunt SS, Luft HS. Effects of surgeon volume and hospital volume on quality of care in hospitals. Med Care. 1987;25:489 503. 811. Dudley RA, Johansen KL, Brand R, et al. Selective referral to high- volume hospitals: estimating potentially avoidable deaths. JAMA. 2000;283:1159 66. 812. Birkmeyer JD, Sun Y, Goldfaden A, et al. Volume and process of care in high-risk cancer surgery. Cancer. 2006;106:2476 81. 813. Birkmeyer JD, Finlayson SR, Tosteson AN, et al. Effect of hospital volume on in-hospital mortality with pancreaticoduodenectomy. Surgery. 1999;125:250 6. 814. Birkmeyer JD, Warshaw AL, Finlayson SR, et al. Relationship between hospital volume and late survival after pancreaticoduode- nectomy. Surgery. 1999;126:178 83. 815. Birkmeyer JD. High-risk surgery follow the crowd. JAMA. 2000; 283:1191 3. 816. Birkmeyer JD, Lucas FL, Wennberg DE. Potential benefits of region- alizing major surgery in Medicare patients. Eff Clin Pract. 1999;2: 277 83. 817. Birkmeyer JD. Should we regionalize major surgery? Potential benefits and policy considerations. J Am Coll Surg. 2000;190:341 9. 818. Birkmeyer JD, Siewers AE, Finlayson EV, et al. Hospital volume and surgical mortality in the United States. N Engl J Med. 2002;346: 1128 37. 819. Birkmeyer JD, Stukel TA, Siewers AE, et al. Surgeon volume and operative mortality in the United States. N Engl J Med. 2003;349: 2117 27. 820. Chang AC, Birkmeyer JD. The volume-performance relationship in esophagectomy. Thorac Surg Clin. 2006;16:87 94. 821. Hollenbeck BK, Wei Y, Birkmeyer JD. 