"This paper investigates the impact of Medicare HMO penetration on the medical care expenditures incurred by Medicare fee-for-service enrollees. We find that increasing penetration leads to reduced health care spending on fee-for-service beneficiaries. In particular, a one percentage point...

"Professional partnerships might facilitate matching between specialized professionals and heterogeneous consumers, particularly where matching across firms is limited by information, incentives or regulation. We examine the extent to which internally-differentiated medical groups promote...