For the past 30 years, research from investigators at Dartmouth has demonstrated large and persistent variations in costs and quality across the US health care system. Beyond simply showing that cost and quality vary by geography, the Dartmouth Atlas has demonstrated that in many communities, care is so fragmented and ineffective that greater spending on Medicare beneficiaries often leads to worse outcomes1,2 because some patients receive services that are redundant and low value and that may even have substantial risks.