广告能否扩大医院服务市场？来自联邦医疗保险（Medicare）的证据

Direct-to-consumer advertising is pervasive in US healthcare markets, but little evidence exists on the effects of advertising by hospitals, second only to drug manufacturers in medical marketing. Advertising may help facilities increase market share by stealing existing patients, expanding the market for hospital care, or both. Regardless, it has important public finance implications due to the large sums of taxpayer funds spent by federal and state governments to subsidize hospital operations and finance care through public insurance programs. This paper provides the first causal evidence on the market expansion effects of hospital advertising. To obtain causal estimates, we leverage the fact that spikes in political advertising significantly crowd out hospital advertising in the same market, motivating an instrumental variables design. Using claims data on the universe of Traditional Medicare beneficiaries, we find that advertising expands aggregate patient volume and spending on inpatient care — though to a modest degree (implied elasticities are 0.06 and 0.05, respectively). Although the overall effect of advertising on hospital outpatient care is small and imprecise, for-profit hospitals obtain higher outpatient Medicare volume and revenue.