William A. Woolston
Department of Economics
579 Serra Mall
Stanford, CA 94305
NBER Working Papers and Publications
|April 2011||How does Risk Selection Respond to Risk Adjustment? Evidence from the Medicare Advantage Program|
with Jason Brown, Mark Duggan, Ilyana Kuziemko: w16977
Governments often contract with private firms to provide public services such as health care and education. To decrease firms' incentives to selectively enroll low-cost individuals, governments frequently "risk-adjust" payments to firms based on enrollees' characteristics. We model how risk adjustment affects selection and differential payments---the government's payments to a firm for covering an individual minus the counterfactual cost had the government directly covered her. We show that firms reduce selection along dimensions included in the risk-adjustment formula, while increasing selection along excluded dimensions. These responses can actually increase differential payments relative to pre-risk-adjustment levels and thus risk adjustment can raise the total cost to the government...
Published: Brown, Jason, Mark Duggan, Ilyana Kuziemko, and William Woolston. 2014. "How Does Risk Selection Respond to Risk Adjustment? New Evidence from the Medicare Advantage Program." American Economic Review, 104(10): 3335-64.
|September 2010||Class Size and Class Heterogeneity|
with Giacomo De Giorgi, Michele Pellizzari: w16405
We study how class size and class composition affect the academic and labor market performance of college students, two crucial policy questions given the secular increase in college enrollment. Our identification strategy relies on the random assignment of students to teaching classes. We find that a one standard deviation increase in class-size results in a 0.1 standard deviation deterioration of the average grade. Further, the effect is heterogeneous as it is stronger for males and lower income students. Also, the effects of class composition in terms of gender and ability appear to be inverse U-shaped. Finally, a reduction of 20 students (one standard deviation) in one's class size has a positive effect on monthly wages of about 80 Euros (115 USD)
or 6% over the average.
Published: Giacomo De Giorgi & Michele Pellizzari & William Gui Woolston, 2012. "Class Size And Class Heterogeneity," Journal of the European Economic Association, European Economic Association, vol. 10(4), pages 795-830, 08. citation courtesy of