Publications

The Influence of Pioneer Investigators on Technology Adoption: Evidence from New Cancer Drugs
With Leila Agha
The Review of Economics and Statistics, March 2018
NBER working paper #20878 | NIH Public Access PMC5947964 | View abstract

Abstract: Local opinion leaders may play a key role in easing information frictions associated with technology adoption. This paper analyzes the influence of physician investigators who lead clinical trials for new cancer drugs. By comparing diffusion patterns across 21 new cancer drugs, we separate correlated regional demand for new technology from information spillovers. Patients in the lead investigator's region are initially 36% more likely to receive the new drug, but utilization converges within four years. We also find that "superstar" physician authors, measured by trial role or citation history, have broader influence than less prominent authors.

The Evolution of Physician Practice Styles: Evidence from Cardiologist Migration
American Economic Journal: Economic Policy, February 2018
NBER working paper #22478 | NIH Public Access PMC5876705 | View abstract

Abstract: Physician treatment choices for observably similar patients vary dramatically across regions. This paper exploits cardiologist migration to disentangle the role of physician- specific factors such as preferences and learned behavior versus environment-level factors such as hospital capacity and productivity spillovers on physician behavior. Physicians starting in the same region and subsequently moving to dissimilar regions practice similarly before the move. After the move, physician behavior in the first year changes by 0.6-0.8 percentage points for each percentage point change in practice environment, with no further changes over time. This suggests environment factors explain between 60-80 percent of regional disparities in physician behavior.

Working Papers

The Mortality and Medical Costs of Air Pollution: Evidence from Changes in Wind Direction
With Tatyana Deryugina, Garth Heutel, Nolan Miller, and Julian Reif
Revise and resubmit, American Economic Review
NBER working paper #22796 | View abstract

Abstract: We estimate the causal effects of acute fine particulate matter (PM 2.5) exposure on mortality and health care use among the US elderly using Medicare administrative data and a novel instrument for air pollution: changes in the local wind direction. We then develop a new methodology that uses machine learning to estimate the number of life-years lost due to PM 2.5. We find that, while unhealthy individuals are disproportionately vulnerable to air pollution, the largest aggregate burden is borne by those with medium life expectancy, who are both vulnerable and comprise a large share of the elderly population.

Adaptation and the Mortality Effects of Temperature across U.S. Climate Regions
With Garth Heutel and Nolan Miller
NBER working paper #23271 | View abstract

Abstract: Using 20 years of data on Medicare beneficiaries, we predict the end-of-century mortality effects of climate change among the U.S. elderly, accounting at the ZIP code level for both adaptation and regional heterogeneity in the temperature-mortality relationship. We find that this relationship varies systematically with current climate, reflecting both beneficial adaptation to frequently-experienced temperatures and harmful de-adaptation to infrequently experienced temperatures. We model adaptation to future climate using the estimated cross-sectional heterogeneity in temperature effects and combine this with projected end-of-century changes in local temperature distributions to make mortality predictions. Incorporating regional heterogeneity into these predictions reverses the conventional wisdom on the regional distribution of climate change effects: cold places bear more, not less, of the burden. Incorporating adaptation yields mortality effects of climate change that are much lower than those estimated without incorporating adaptation.

What Do Workplace Wellness Programs Do? Evidence from the Illinois Workplace Wellness Study
With Damon Jones and Julian Reif
Study website | NBER working paper #24229 | View abstract

Abstract: Workplace wellness programs cover over 50 million workers and are intended to reduce medical spending, increase productivity, and improve well-being. Yet, limited evidence exists to support these claims. We designed and implemented a comprehensive workplace wellness program for a large employer with over 12,000 employees, and randomly assigned program eligibility and financial incentives at the individual level. Over 56 percent of eligible (treatment group) employees participated in the program. We find strong patterns of selection: during the year prior to the intervention, program participants had lower medical expenditures and healthier behaviors than non-participants. However, we do not find significant causal effects of treatment on total medical expenditures, health behaviors, employee productivity, or self-reported health status in the first year. Our 95% confidence intervals rule out 78 percent of previous estimates on medical spending and absenteeism. Our selection results suggest these programs may act as a screening mechanism: even in the absence of any direct savings, differential recruitment or retention of lower-cost participants could result in net savings for employers.

External summaries: The NBER Digest, J-PAL North America
Does When You Die Depend on Where You Live? Evidence from Hurricane Katrina
With Tatyana Deryugina
View abstract

Abstract: We follow Medicare cohorts over time and space to estimate Hurricane Katrina's long-run mortality effects on elderly and disabled victims initially living in New Orleans. Inclusive of the initial shock, the hurricane improved survival eight years past the storm by 1.74 percentage points. Migration to lower-mortality regions explains most of this survival increase. Migrants to low- versus high-mortality regions look similar at baseline, but migrants' subsequent mortality is 0.83-0.90 percentage points lower for each percentage-point reduction in local mortality, quantifying causal effects of place on mortality among this population. By contrast, migrants' mortality is unrelated to local Medicare spending.

Air Pollution and the Labor Market: Evidence from Wildfire Smoke
With Mark Borgschulte and Eric Zou
View abstract

Abstract: We estimate labor market responses to transient air pollution events using a novel linkage of satellite images of wildfire smoke plumes, pollution monitor data, and labor market outcomes in the United States. Smoke exposure reduces earnings in both the year of exposure and the following year, lowers labor force participation, and increases Social Security claiming and payments. With an average of 17 days of annual smoke exposure per person, earnings losses sum to 1.21 percent of annual labor income. We estimate that the welfare cost of these lost earnings is substantially higher than the mortality cost of wildfire smoke.

Work in Progress

Why Does Disability Increase During Recessions? Evidence from Medicare
With Colleen Carey and Nolan Miller
Draft available upon request
Blowing Smoke: Health Impacts of Wildfire Plume Dynamics
With Nolan Miller and Eric Zou

Other Writing