When retail clinics entered the U.S. health care market more than a decade ago, they were greeted with high expectations. The hope was their lower cost structure and focus on convenience and price transparency — two things sorely lacking in traditional health care — would engender radical changes. Retail clinics have demonstrated that they are a sustainable business model and clearly fit a patient need: Today, there are more than 1,600 clinics across the country, which have had a total of 20 million patient visits. Nonetheless, their performance has been disappointing: Their growth has been less than expected, they have not expanded care to underserved markets (namely, the poor), and their impact on health care spending — helping to lower it — remains unclear.