Michael R. Richards M.D., Ph.D., M.P.H., Catherine T. Smith B.S., Amy J. Graves S.M., M.P.H., Melinda B. Buntin Ph.D., Matthew J. Resnick M.D., M.P.H., M.M.H.C.
To calculate physician concentration levels for all U.S. markets using detailed data on integration and accountable care organization () participation.
2015 &A office‐based physician survey linked to all commercial and public payer s.
We construct three separate Herfindahl–Hirschman Index () measures and plot their distributions. We then investigate how prevailing levels of concentration change when incorporating more detailed organizational features into the measure.
Horizontal and vertical integration strongly influences measures of physician concentration; however, s have limited impact overall. s are often present in competitive markets, and only in a minority of these markets do s substantively increase physician concentration.
Monitoring effects on physician competition will likely have to proceed on a case‐by‐case basis.