Person: Alsan, Marcella
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Publication Investigator Racial Diversity and Clinical Trial Participation
(Harvard Kennedy School, 2023-10) Alsan, Marcella; Campbell, Romaine; Leister, Lukas; Ojo, AyotomiwaWe investigate whether increased racial diversity of clinical trial principal investigators could increase the enrollment of Black patients, which currently lags population and disease-burden shares. We conducted a survey experiment in which respondents were shown a photo of a current NIH investigator in which race (Black/White) was randomized. Sex was also randomized as a relevant benchmark. Black respondents reported 0.35 standard deviation units higher interest in participating in a clinical study led by a race concordant investigator (a 12.6% increase). Sex concordance had no effect. Further analyses indicate that perceived trustworthiness and attractiveness are the most important factors explaining these results.
Publication Representation and Extrapolation: Evidence from Clinical Trials
(Harvard Kennedy School, 2022-10) Alsan, Marcella; Durvasula, Maya; Gupta, Harsh; Schwartzstein, Joshua; Williams, Heidi L.This article examines the consequences and causes of low enrollment of Black patients in clinical trials. We develop a simple model of similarity-based extrapolation that predicts that evidence is more relevant for decision-making by physicians and patients when it is more representative of the group that is being treated. This generates the key result that the perceived benefit of a medicine for a group depends not only on the average benefit from a trial, but also on the share of patients from that group who were enrolled in the trial. In survey experiments, we find that physicians who care for Black patients are more willing to prescribe drugs tested in representative samples, an effect substantial enough to close observed gaps in the prescribing rates of new medicines. Black patients update more on drug efficacy when the sample that the drug is tested on is more representative, reducing Black-White patient gaps in beliefs about whether the drug will work as described. Despite these benefits of representative data, our framework predicts that those who have benefited more from past medical breakthroughs are less costly to enroll in the present, leading to persistence in who is represented in the evidence base.
Publication The Health of Democracies During the Pandemic: Results from a Randomized Survey Experiment
(Harvard Kennedy School, 2023-01) Alsan, Marcella; Braghieri, Luca; Eichmeyer, Sarah; Kim, Minjeong Joyce; Stantcheva, Stefanie; Yang, David YConcerns have been raised about the “demise of democracy”, possibly accelerated by pandemic-related restrictions. Using a survey experiment involving 8,206 respondents from five Western democracies, we find that subjects randomly exposed to information regarding civil liberties infringements undertaken by China and South Korea to contain COVID-19 became less willing to sacrifice rights and more worried about their long-term-erosion. However, our treatment did not increase support for democratic procedures more generally, despite our prior evidence that pandemic-related health risks diminished such support. These results suggest that the start of the COVID-19 crisis was a particularly vulnerable time for democracies.
Publication The Impact of Large-Scale Social Media Advertising Campaigns on COVID-19 Vaccination: Evidence from Two Randomized Controlled Trials
(Harvard Kennedy School, 2022-11) Ho, Lisa; Breza, Emily; Alsan, Marcella; Banerjee, Abhijit; Chandrasekhar, Arun G.; Stanford, Fatima; Fior, Renato; Goldsmith-Pinkham, Paul; Holland, Kelly; Hoppe, Emily; Jean, Louis-Maël; Ogbu-Nwobodo, Lucy; Olken, Benjamin A.; Torres, Carlos; Vautrey, Pierre-Luc; Warner, Erica; Duflo, EstherCOVID-19 vaccines are widely available in wealthy countries, yet many people remain unvaccinated. Understanding the effectiveness -- or lack thereof -- of popular vaccination campaign strategies is therefore critical. In this paper, we report results from two studies that tested strategies central to current vaccination outreach: (1) direct communication by health professionals addressing questions about vaccination and (2) efforts to motivate individuals to promote vaccination within their social networks. Near the peak of the Omicron wave, doctor- and nurse-produced videos were disseminated to 17.8 million Facebook users in the US and 11.5 million in France. In both countries, we cannot reject the null of no effect of any of the interventions on any of the outcome variables (first doses - US and France, second doses and boosters - US). We can reject very small effects on first doses during the interventions in both countries (0.16pp - US, 0.021pp - France). In contrast with similar campaigns earlier in the pandemic to encourage health-preserving behaviors, messaging at this stage of the pandemic -- whether aimed at the unvaccinated or those tasked with encouraging others -- did not change vaccination decisions.