NBER Publications by Tom Chang

Contact and additional information for this authorAll publicationsWorking Papers only

Working Papers and Chapters

February 2014Particulate Pollution and the Productivity of Pear Packers
with Joshua Graff Zivin, Tal Gross, Matthew Neidell: w19944
We study the effect of outdoor air pollution on the productivity of indoor workers at a pear-packing factory. We focus on fine particulate matter (PM2.5), a harmful pollutant that easily penetrates indoor settings. We find that an increase in PM2.5 outdoors leads to a statistically and economically significant decrease in packing speeds inside the factory, with effects arising at levels well below current air quality standards. In contrast, we find little effect of PM2.5 on hours worked or the decision to work, and little effect of pollutants that do not travel indoors, such as ozone. This effect of outdoor pollution on the productivity of indoor workers suggests a thus far overlooked consequence of pollution. Back-of-the-envelope calculations suggest that nationwide reductions in PM2.5 fr...
July 2013Physician Agency and Competition: Evidence from a Major Change to Medicare Chemotherapy Reimbursement Policy
with Mireille Jacobson, Joseph P. Newhouse, Craig C. Earle, M.D.: w19247
We investigate the role of physician agency and competition in determining health care supply and patient outcomes. A 2005 change to Medicare fees had a large, negative impact on physician profit margins for providing chemotherapy treatment. In response to these cuts, physicians increased their provision of chemotherapy and changed the mix of chemotherapy drugs they administered. The increase in treatment improved patient survival. These changes were larger in states that experienced larger decreases in physician profit margins. Finally while physician response was larger in more competitive markets, survival improvements were larger in less competitive markets.
December 2010Natural Disaster Management: Earthquake Risk and Hospitals' Provision of Essential Services in California
with Mireille Jacobson
in Regulation vs. Litigation: Perspectives from Economics and Law, Daniel P. Kessler, editor

Contact and additional information for this authorAll publicationsWorking Papers only


National Bureau of Economic Research, 1050 Massachusetts Ave., Cambridge, MA 02138; 617-868-3900; email:

Contact Us