Edward H. Chang

• Katherine L. Milkman, Linnea Gandhi, Mitesh Patel, Heather N. Graci, Dena Gromet, Hung Ho, Joseph S. Kay, Timothy W. Lee, Jake Rothschild, Jonathan E. Bogard, Ilana Brody, Christopher F. Chabris, Edward Chang, Gretchen B. Chapman, Jennifer E. Dannals, Noah J. Goldstein, Amir Goren, Hal E. Hershfield, Alexander Hirsch, Jillian Hmurovic, Samantha Horn, Dean Karlan, Ariella Kristal, Cait Lamberton, M. Meyer, Allison H. Oakes, Maurice Schweitzer, Maheen Shermohammed, Joachim H. Talloen, Caleb Warren, Ashley Whillans, Kuldeep N. Yadav, Julian J. Zlatev, Ron Berman, Chalanda N. Evans, Rahul Ladhania, Jens Ludwig, Nina Mazar, Sendhil Mullainathan, Christopher K. Snider, Jann Spiess, Eli Tsukayama, Lyle Ungar, Christophe Van den Bulte, Kevin Volpp, Angela Duckworth (2022), A 680,000-Person Megastudy of Nudges to Encourage Vaccination in Pharmacies, Proceedings of the National Academy of Sciences, 119 (6). 10.1073/pnas.211512611 Abstract

  Encouraging vaccination is a pressing policy problem. To assess whether text-based reminders can encourage pharmacy vaccination and what kinds of messages work best, we conducted a megastudy. We randomly assigned 689,693 Walmart pharmacy patients to receive one of 22 different text reminders using a variety of different behavioral science principles to nudge flu vaccination or to a business-as-usual control condition that received no messages. We found that the reminder texts that we tested increased pharmacy vaccination rates by an average of 2.0 percentage points, or 6.8%, over a 3-mo follow-up period. The most effective messages reminded patients that a flu shot was waiting for them and delivered reminders on multiple days. The top performing intervention included two texts delivered 3 d apart and communicated to patients that a vaccine was “waiting for you.” Neither experts nor lay people anticipated that this would be the best-performing treatment, underscoring the value of simultaneously testing many different nudges in a highly powered megastudy.

• Erika Kirgios, Aneesh Rai, Edward Chang, Katy Milkman (2022), When Seeking Help, Women and Racial/Ethnic Minorities Benefit From Explicitly Stating Their Identity, Nature Human Behaviour, 6 (), pp. 383-391. Abstract

  Receiving help can make or break a career, but women and racial/ethnic minorities do not always receive the support they seek. Across two audit experiments—one with politicians and another with students—as well as an online experiment (total n= 5,145), we test whether women and racial/ethnic minorities benefit from explicitly mentioning their demographic identity in requests for help, for example, by including statements like “As a Black woman…” in their communications. We propose that when a help seeker highlights their marginalized identity, it may activate prospective helpers’ motivations to avoid prejudiced reactions and increase their willingness to provide support. Here we show that when women and racial/ethnic minorities explicitly mentioned their demographic identity in help-seeking emails, politicians and students responded 24.4% (7.42 percentage points) and 79.6% (2.73 percentage points) more often, respectively. These findings suggest that deliberately mentioning identity in requests for help can improve outcomes for women and racial/ethnic minorities.

• Katherine L. Milkman, Dena Gromet, Hung Ho, Joseph S. Kay, Timothy W. Lee, Predrag Pandiloski, Yeji Park, Aneesh Rai, Max Bazerman, John Beshears, Lauri Bonacorsi, Colin Camerer, Edward Chang, Gretchen B. Chapman, Robert Cialdini, Hengchen Dai, Lauren Eskreis-Winkler, Ayelet Fishbach, James J. Gross, Samantha Horn, Alexa Hubbard, Steven J. Jones, Dean Karlan, Tim Kautz, Erika Kirgios, Joowon Klusowski, Ariella Kristal, Rahul Ladhania, George Loewenstein, Jens Ludwig, Barbara Mellers, Sendhil Mullainathan, Silvia Saccardo, Jann Spiess, Gaurav Suri, Joachim H. Talloen, Jamie Taxer, Yaacov Trope, Lyle Ungar, Kevin Volpp, Ashley Whillans, Jonathan Zinman, Angela Duckworth (2021), Megastudies Improve the Impact of Applied Behavioural Science, , 600 (), pp. 478-483. Abstract

  Policy-makers are increasingly turning to behavioural science for insights about how to improve citizens’ decisions and outcomes. Typically, different scientists test different intervention ideas in different samples using different outcomes over different time intervals. The lack of comparability of such individual investigations limits their potential to inform policy. Here, to address this limitation and accelerate the pace of discovery, we introduce the megastudy—a massive field experiment in which the effects of many different interventions are compared in the same population on the same objectively measured outcome for the same duration. In a megastudy targeting physical exercise among 61,293 members of an American fitness chain, 30 scientists from 15 different US universities worked in small independent teams to design a total of 54 different four-week digital programmes (or interventions) encouraging exercise. We show that 45% of these interventions significantly increased weekly gym visits by 9% to 27%; the top-performing intervention offered microrewards for returning to the gym after a missed workout. Only 8% of interventions induced behaviour change that was significant and measurable after the four-week intervention. Conditioning on the 45% of interventions that increased exercise during the intervention, we detected carry-over effects that were proportionally similar to those measured in previous research. Forecasts by impartial judges failed to predict which interventions would be most effective, underscoring the value of testing many ideas at once and, therefore, the potential for megastudies to improve the evidentiary value of behavioural science.

• Edward Chang, Erika Kirgios, Rosanna Smith (2021), Large-scale field experiment shows null effects of team demographic diversity on outsiders’ willingness to support the team, . Abstract

  Demographic diversity in the United States is rising, and increasingly, work is conducted in teams. These co-occurring phenomena suggest that it might be increasingly common for work to be conducted by demographically diverse teams. But to date, in spite of copious field experimental evidence documenting that individuals are treated differently based on their demographic identity, we have little evidence from field experiments to establish how and whether teams are treated differently based on their levels of demographic diversity. To answer this question, we present the results of a preregistered, large-scale (n=9496) field experiment testing whether team demographic diversity affects outsiders’ responses to the team. Participants were asked via email to donate money to support the work of a team that was described and depicted as demographically diverse, or not. Even though the study was well-powered to detect even small effects (i.e., differences of less than 1.5 percentage points in donation rates), we found no significant differences in people’s willingness to donate to a more diverse versus a less diverse team. We also did not find moderation by participant gender, racial diversity of the participant’s zip code, or political leaning of the participant’s zip code, suggesting that the lack of a main effect is not due to competing mechanisms cancelling out a main effect. These results suggest past research on the effects of demographic diversity on team support may not generalize to the field, highlighting the need for additional field experimental research on people’s responses to demographically diverse teams.

• Erika Kirgios, Edward Chang, Emma E. Levine, Katherine L. Milkman, Judd B. Kessler (2020), Forgoing Earned Incentives to Signal Pure Motives, Proceedings of the National Academy of Sciences, 117 (29), pp. 16891-16897. Abstract

  Financial incentives can spark behavior change but often damage recipients’ self-image. We designed and tested an intervention that allows organizations and individuals to resolve this tension. We motivated actors with financial rewards and then gave them the opportunity to forgo those rewards to signal their past actions were intrinsically motivated. We propose that actors who forgo financial rewards engage in “motivation laundering,” passing up payments earned for an incentivized action to retroactively signal that their motivations were intrinsic. Our intervention has the potential to leave organizations and incentivized individuals better off: Financial rewards help actors build better habits, and motivation laundering allows them to boost their self-image, while giving organizations opportunities to lower incentive program costs.

• Erika Kirgios, Edward Chang, Katherine L. Milkman (2020), Going It Alone: Competition Increases the Attractiveness of Minority Status, Organizational Behavior and Human Decision Processes, 161 (), pp. 20-33. Abstract

  Past research demonstrates that people prefer to affiliate with others who resemble them demographically. However, we posit that the strength of this tendency toward homophily may be moderated by strategic considerations when competing for scarce opportunities. Across six experiments, we find that anticipated competition weakens people’s desire to join groups that include similar others. When expecting to compete against fellow group members, women are more willing to join all-male groups and Black participants are more willing to join all-White groups than in the absence of competition. We show that this effect is mediated both by a belief that being distinct will lead your performance to stand out and by a desire to compete against demographically dissimilar others. Our findings offer a new perspective to enrich past research on homophily, shedding light on the instances when minorities are more likely to join groups in which they will be underrepresented.

• Edward Chang, Erika Kirgios, Aneesh Rai, Katherine L. Milkman (2020), The Isolated Choice Effect and Its Implications for Gender Diversity in Organizations, Management Science, 66 (6), pp. 2752-2761. Abstract

  We highlight a feature of personnel selection decisions that can influence the gender diversity of groups and teams. Specifically, we show that people are less likely to choose candidates whose gender would increase group diversity when making personnel selections in isolation (i.e., when they are responsible for selecting a single group member) than when making collections of choices (i.e., when they are responsible for selecting multiple group members). We call this the isolated choice effect. Across 6 preregistered experiments (n=3,509), we demonstrate that the isolated choice effect has important consequences for group diversity. When making sets of hiring and selection decisions (as opposed to making a single hire), people construct more gender-diverse groups. Mediation and moderation studies suggest that people do not attend as much to diversity when making isolated selection choices, which drives this effect.

• Chang, E.H. and Katherine L. Milkman (2020), Improving Decisions that Impact Gender Equality in the Workplace, Organizational Dynamics, Vol. 49, No. 1, 1-7.
• Edward Chang, Katherine L. Milkman, Dena Gromet, Reb Rebele, Cade Massey, Angela Duckworth, Adam Grant (2019), The Mixed Effects of Online Diversity Training, Proceedings of the National Academy of Sciences, 116 (15), pp. 7778-7783. Abstract

  We present results from a large (n = 3,016) field experiment at a global organization testing whether a brief science-based online diversity training can change attitudes and behaviors toward women in the workplace. Our preregistered field experiment included an active placebo control and measured participants’ attitudes and real workplace decisions up to 20 weeks postintervention. Among groups whose average untreated attitudes—whereas still supportive of women—were relatively less supportive of women than other groups, our diversity training successfully produced attitude change but not behavior change. On the other hand, our diversity training successfully generated some behavior change among groups whose average untreated attitudes were already strongly supportive of women before training. This paper extends our knowledge about the pathways to attitude and behavior change in the context of bias reduction. However, the results suggest that the one-off diversity trainings that are commonplace in organizations are unlikely to be stand-alone solutions for promoting equality in the workplace, particularly given their limited efficacy among those groups whose behaviors policymakers are most eager to influence.

• Edward Chang, Katherine L. Milkman, Dolly Chugh, Modupe Akinola (2019), Diversity Thresholds: How Social Norms, Visibility, and Scrutiny Relate to Group Composition, Academy of Management Journal, 62 (1), pp. 144-171. Abstract

  Across a field study and four experiments, we examine how social norms and scrutiny affect decisions about adding members of underrepresented populations (e.g., women, racial minorities) to groups. When groups are scrutinized, we theorize that decision makers strive to match the diversity observed in peer groups due to impression management concerns, thereby conforming to the descriptive social norm. We examine this first in the context of U.S. corporate boards, where firms face pressure to increase gender diversity. Analyses of S&P 1500 boards reveal that significantly more boards include exactly two women (the descriptive social norm) than would be expected by chance. This overrepresentation of two-women boards—a phenomenon we call “twokenism”—is more pronounced among more visible companies, consistent with our theorizing around impression management and scrutiny. Experimental data corroborate these findings and provide support for our theoretical mechanism: decision makers are discontinuously less likely to add a woman to a board once it includes two women (the social norm), and decision makers’ likelihood of adding a woman or minority to a group is influenced by the descriptive social norms and scrutiny faced. Together, these findings provide a new perspective on the persistent underrepresentation of women and minorities in organizations.

Paul R. Kleindorfer Scholar Award, 2018

Baker Retailing Center Grant, 2018–2020

Graduate Student Travel Award, Society for Personality and Social Psychology, 2018

Best Micro Paper, East Coast Doctoral Conference, 2017

Winkelman Fellowship, 2017–2020

Best Student Paper, Society for Judgment and Decision Making Conference, 2016

Marjorie Weiler Prize for Excellence in Writing, 2016

Russell Ackoff Doctoral Student Fellowship, 2016, 2017

Wharton Doctoral Programs Travel Grant, 2016, 2017

Graduate and Professional Student Assembly of the University of Pennsylvania Travel Grant, 2016, 2017

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