Recently, 3 major medical centers鈥擠artmouth, Johns Hopkins, and the University of Michigan鈥攄eclared a 鈥渧olume pledge鈥� that restricts performance of 10 selected procedures to surgeons and hospitals that meet volume criteria.¹ This followed an announcement by US News & World Report of a new analysis demonstrating poorer outcomes at low-volume hospitals.¹ Both of these are derived from decades of research showing that high surgical volumes are associated with better outcomes, especially in high-risk procedures.^2,3

Stakeholders have responded to the volume-outcome literature by calling for selective referral to high-volume facilities and in some cases enforced this by only reimbursing facilities that meet certain volume criteria.⁴ For the past decade, the Leapfrog Group (a coalition of health care purchasers) has called for 鈥渆vidence-based hospital referral鈥� to facilities meeting their volume targets. Medicare also set minimum volumes for bariatric surgery reimbursement in 2006 and for solid organ transplants in 2007.