Leemore, Dafny; David, Dranove; Frank, Limbrock; Fiona, … - In: The B.E. Journal of Economic Analysis & Policy 11 (2011) 2, pp. 1-24
We compare four datasets that researchers might use to study competition in the health insurance industry. We show that the two datasets most commonly used to estimate market concentration differ considerably from each other (both in levels and in changes over time), and reflect implausibly high...