​The Affordable Care Act (ACA) has created a greater degree of standardization of health insurance plans than has ever existed in the individual (non-group) health insurance market. As a result, one of the most significant remaining features of health plans that can vary considerably is the number of doctors and hospitals contracting with each health plan. “Narrow networks” has led to some concern that those buying health insurance in the individual market, both inside and outside the Exchanges, now face more restricted access to doctors and hospitals in their immediate geographic area. Gerald Kominski, the Center’s director, summarizes what is known about narrow networks from the research literature; discusses challenges in defining and measuring network adequacy; and proposes further research to determine whether narrow networks are necessarily associated with lower quality care.