NATIONAL BUREAU OF ECONOMIC RESEARCH
NATIONAL BUREAU OF ECONOMIC RESEARCH

NBER Publications by Vivian Wu

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Working Papers and Chapters

March 2011The Long-term Impact of Medicare Payment Reductions on Patient Outcomes
with Yu-Chu Shen: w16859
This study examines the long term impact of Medicare payment reductions on patient outcomes using a natural experiment - the Balance Budget Act (BBA) of 1997. We use predicted Medicare revenue changes due to BBA, with simulated BBA payment cuts as an instrument, to categorize hospitals by degrees of payment cuts (small, moderate, or large), and follow Medicare patient outcomes in these hospitals over a 11 year panel: 1995-1997 pre-BBA, 1998-2000 initial years of BBA, and 2001-2005 post-BBA years. We find that Medicare AMI mortality trends stay similar across hospitals when comparing between pre-BBA and initial-BBA periods. However, the trends began to diverge in 2001-2005: hospitals facing large payment cuts saw increased mortality rates relative to that of hospitals facing small cuts in ...
February 2008The Changing Effect of HMO Market Structure: An Analysis of Penetration, Concentration, and Ownership Between 1994-2005
with Yu-Chu Shen, Glenn Melnick: w13775
We analyze the role of three aspects of HMO market structure -- HMO penetration, HMO plan concentration, and HMO for-profit share on explaining hospital cost and revenue growth during the HMO expansion period (1994-1999) and backlash period (2000-2005). We find that HMO penetration effects differ over time: a 10 percentage point increase in HMO enrollment leads to 2.5 percent reduction in cost and revenues in the expansion period but only 0.4-1 percent reduction in the backlash period. Furthermore, this HMO backlash effect can be attributed to HMO dis-enrollment as well as the changing nature of HMO product. We find that revenue increases at a slower rate (by about 5 percent) in markets with relatively concentrated HMO markets power and more competitive hospital markets. Finally, increa...

Contact and additional information for this authorAll papers and publicationsWorking Papers onlyWorking Papers with publication info

 
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