Narrow Networks on the Health Insurance Marketplaces: What Hospitals are In or Out and How Does it Affect Premiums and Consumer Choices?

The Health Insurance Marketplaces have stimulated significant growth in narrow network products.  Little is known about which providers are excluded from these products, the effects of these exclusions on premiums, or the value of different insurance products (and associated networks) to consumers.  We address this gap by leveraging a novel dataset containing the identities of in-network hospitals in each silver plan offered on the HIMs of eight states in 2014 and 2015.  These states are broadly geographically representative, span different exchange governances, and cover roughly 43 percent of the US population.  We examine  three key questions: (1) what hospital, insurer, and market characteristics affect network inclusion?  (2) how does network breadth (measured in various ways) affect pricing? (3) how willing are consumers to accept narrower networks in exchange for lower prices?