The impact of comparative effectiveness research on health and health care spending.

Comparative effectiveness research (CER) is thought to identify what works and does not work in health care. We interpret CER as infusing evidence on product quality into markets, shifting the relative demand for products in CER studies. We analyze how shifts in demand affect health and health care spending and demonstrate that CER may raise or lower overall health when treatments have heterogeneous effects, but payers respond with product-specific coverage policies. Among patients with schizophrenia, we calibrate that subsidy policies based on the clinical trial CATIE may have reduced overall health by inducing some patients to switch away from schizophrenia treatments that were effective for them towards winners of the CER.