<Emphasis Type="Bold">Objective: To estimate rates of non-adherence for statins following implementation of a preferred drug list (PDL). <Emphasis Type="Bold">Study design: A retrospective cohort study. <Emphasis Type="Bold">Methods: A difference-in-difference-in-difference approach was used to estimate the impact of a PDL on the use of statins in an Alabama...</emphasis></emphasis></emphasis>

Theory predicts intense price competition results when firms cluster with rivals. Yet, strong evidence of clustering is found in previous empirical research. Researchers typically measure clustering by comparing observed location patterns to random assignment. The random assignment benchmark...

"Why do businesses such as fast-food restaurants, coffee shops, and hotels cluster? In the classic analysis of Hotelling, firms cluster to attract consumers who have travel costs. We present an alternative model where firms cluster because one firm is free riding on another firm's information...

Pharmaceutical manufacturers have increased the availability of their products and sometimes increased their own financial returns by charging lower prices outside of the US and by discounting to lower-income patients in the US. Examples include discounted HIV-AIDS drugs in developing countries...