Working Papers

Funding of Clinical Trials and Reported Drug Efficacy

Abstract: Clinical trials are a key determinant of drug approvals and also influence prescription decisions. In recent years, an increasing share of clinical trials have been funded by pharmaceutical firms, as opposed to by the public sector. This paper estimates the effect of financial sponsorship on reported drug efficacy, leveraging the insight that the exact same sets of drugs are often compared in different randomized control trials conducted by parties with different financial interests. In principle, randomized control trials comparing the same drugs should yield comparable estimates, regardless of the interests of the trial's funders. In practice, I use newly assembled data on hundreds of psychiatric clinical trials to estimate that a drug appears 0.15 standard deviations more effective when the trial is sponsored by that drug's manufacturer, compared with the same drug in the same trial without the drug manufacturer's involvement. Observable characteristics of trial design and patient enrollment explain little of this effect. In contrast, sponsored papers with non-positive results are more likely to remain unpublished. Back-of-the-envelope calculations suggest this publication mechanism can account for nearly half of the sponsorship effect. The sponsorship effect decreases over time as pre-registration requirements were implemented, which is suggestive that pre-registration may be effective in overcoming sponsorship bias.

Screening and Selection: The Case of Mammograms (with Liran Einav, Amy Finkelstein, Abigail Ostriker, and Heidi Williams), American Economic Review, 110(12), December 2020: 3836-3870.

Abstract: We analyze selection into screening in the context of recommendations that breast cancer screening start at age 40. Combining medical claims with a clinical oncology model, we document that compliers with the recommendation are less likely to have cancer than younger women who select into screening or women who never screen. We show this selection is quantitatively important: shifting the recommendation from age 40 to 45 results in three times as many deaths if compliers were randomly selected than under the estimated patterns of selection. The results highlight the importance of considering characteristics of compliers when making and designing recommendations.

Press: Science, Marginal Revolution


Outpatient Wait Times and Quality of Care for Medicaid Patients (with Amy Finkelstein and Liran Einav), Health Affairs, 36(5), May 2017: 826-832. Online Appendix.

Abstract: The time patients spend in a doctor’s waiting room prior to a scheduled appointment is an important component of the quality of the overall health care experience. We analyzed data on twenty-one million outpatient visits obtained from electronic health record systems, which allowed us to measure time spent in the waiting room beyond the scheduled appointment time. Median wait time was a little more than four minutes. Almost one-fifth of visits had waits longer than twenty minutes, and 10 percent were more than thirty minutes. Waits were shorter for early-morning appointments, for younger patients, and at larger practices. Median wait time was 4.1 minutes for privately insured patients and 4.6 minutes for Medicaid patients. After adjustment for patient and appointment characteristics, Medicaid patients were 20 percent more likely than the privately insured patients to wait longer than twenty minutes, with most of this disparity explained by differences in practices and providers they saw. Wait times for Medicaid patients relative to privately insured patients were longer in states with relatively lower Medicaid reimbursement rates. The study complements other work that suggests that Medicaid patients face some additional barriers in the receipt of care.

Press: MIT News, Brookings