Katherine L. Milkman

Katherine L. Milkman
  • James G. Dinan Endowed Professor
  • Professor of Operations, Information and Decisions

Contact Information

  • office Address:

    3730 Walnut Street
    566 Jon M. Huntsman Hall
    Philadelphia, PA 19104

Research Interests: behavioral economics, judgment and decision making, behavior change

Links: CV, Personal Website, Behavior Change for Good Initiative

Overview

Katy Milkman is the James G. Dinan Professor at The Wharton School of the University of Pennsylvania and holds a secondary appointment at Penn’s Perelman School of Medicine. Her research explores ways that insights from economics and psychology can be harnessed to change consequential behaviors for good, such as savings, exercise, student achievement, vaccination and discrimination. To that end, she co-founded and co-directs the Behavior Change for Good Initiative at the University of Pennsylvania.

In both 2021 and 2023 Katy was named one of the world’s top 50 management thinkers by Thinkers50 and in 2021 she was also named the world’s top strategy thinker. The New York Times also named her bestselling book How to Change: The Science of Getting from Where You Are to Where You Want to Be one of the eight best books for healthy living in 2021.

Katy is the former president of the Society for Judgment and Decision Making, a TEDx speaker, an APS Fellow, and the host of Charles Schwab’s popular behavioral economics podcast, Choiceology. She has published dozens of research articles in leading academic journals such as Nature and the Proceedings of the National Academy of Sciences, and her findings are regularly covered by major media outlets. She has worked with or advised numerous organizations on behavior change, including The White House, Google, Walmart, Humana, the U.S. Department of Defense, 24 Hour Fitness and the American Red Cross. 

Katy frequently writes op-eds about topics related to behavioral science, and her writing has appeared in The New York Times, The Washington Post, The Economist and Scientific American.  She is a repeated recipient of excellence in teaching awards from Wharton’s undergraduate and MBA divisions, and in one particularly proud moment was voted Wharton’s “Iron Prof” by the school’s MBA students for a PechaKucha-style presentation of her research. 

Katy earned her undergraduate degree from Princeton University (summa cum laude), where she studied Operations Research and American Studies, and her PhD from Harvard University where she studied Computer Science and Business.

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Research

  • Jose A. Cervantez and Katherine L. Milkman (2024), Can Nudges Be Leveraged to Enhance Diversity in Organizations? A Systematic Review, Current Opinion in Psychology. https://doi.org/10.1016/j.copsyc.2024.101874 Abstract

    In this article, we review and summarize key findings from a growing literature exploring how nudges can facilitate efforts to diversify organizations. Nudges are psychologically-informed interventions that change behavior without restricting choice or altering incentives. We focus on two types of nudges to enhance organizational diversity: (1) nudges that target organizational processes directly or the decision makers who oversee them to increase the diversity of those hired and promoted and (2) nudges that target the underrepresented candidates themselves to increase the diversity of those applying for organizational roles. We categorize nudges designed to enhance organizational diversity, both by their target and based on the psychology they leverage to improve outcomes for women and racial minorities.

  • Linda W. Chang, Erika Kirgios, Sendhil Mullainathan, Katherine L. Milkman (2024), Does Counting Change What Counts? Quantification Fixation Biases Decision Making, Proceedings of the National Academy of Sciences. https://doi.org/10.1073/pnas.2400215121 Abstract

    People often rely on numeric metrics to make decisions and form judgments. Numbers can be difficult to process, leading to their underutilization, but they are also uniquely suited to making comparisons. Do people decide differently when some dimensions of a choice are quantified and others are not? We explore this question across 21 preregistered experiments (8 in the main text, N = 9,303; 13 in supplement, N = 13,936) involving managerial, policy, and consumer decisions. Participants face choices that involve tradeoffs (e.g., choosing between employees, one of whom has a higher likelihood of advancement but lower likelihood of retention), and we randomize which dimension of each tradeoff is presented numerically and which is presented qualitatively (using verbal estimates, discrete visualizations, or continuous visualizations). We show that people systematically shift their preferences toward options that dominate on tradeoff dimensions conveyed numerically—a pattern we dub “quantification fixation.” Further, we show that quantification fixation has financial consequences—it emerges in incentive-compatible hiring tasks and in charitable donation decisions. We identify one key mechanism that underlies quantification fixation and moderates its strength: When making comparative judgments, which are essential to tradeoff decisions, numeric information is more fluent than non-numeric information. Our findings suggest that when we count, we change what counts.

  • Katherine L. Milkman, Sean F. Ellis, Dena Gromet, Alex S. Luscher, Rayyan S. Mobarak, Madeline K. Paxson, Ramon A. Silvera Zumaran, Robert Kuan, Ron Berman, Neil A. Lewis Jr. John A. List, Mitesh S. Patel, Christophe Van den Bulte, Kevin G. Volpp, Maryann V. Beauvais, Jonathan K. Bellows, Cheryl A. Marandola, Angela Duckworth (2024), Megastudy Shows That Reminders Boost Vaccination But Adding Free Rides Does Not, Nature. https://doi.org/10.1038/s41586-024-07591-x Abstract

    Encouraging routine COVID-19 vaccinations is likely to be a crucial policy challenge for decades to come. To avert hundreds of thousands of unnecessary hospitalizations and deaths, adoption will need to be higher than it was in the autumn of 2022 or 2023, when less than one-fifth of Americans received booster vaccines. One approach to encouraging vaccination is to eliminate the friction of transportation hurdles. Previous research has shown that friction can hinder follow-through and that individuals who live farther from COVID-19 vaccination sites are less likely to get vaccinated. However, the value of providing free round-trip transportation to vaccination sites is unknown. Here we show that offering people free round-trip Lyft rides to pharmacies has no benefit over and above sending them behaviourally informed text messages reminding them to get vaccinated. We determined this by running a megastudy with millions of CVS Pharmacy patients in the United States testing the effects of (1) free round-trip Lyft rides to CVS Pharmacies for vaccination appointments and (2) seven different sets of behaviourally informed vaccine reminder messages. Our results suggest that offering previously vaccinated individuals free rides to vaccination sites is not a good investment in the United States, contrary to the high expectations of both expert and lay forecasters. Instead, people in the United States should be sent behaviourally informed COVID-19 vaccination reminders, which increased the 30-day COVID-19 booster uptake by 21% (1.05 percentage points) and spilled over to increase 30-day influenza vaccinations by 8% (0.34 percentage points) in our megastudy. More rigorous testing of interventions to promote vaccination is needed to ensure that evidence-based solutions are deployed widely and that ineffective but intuitively appealing tools are discontinued.

  • Aneesh Rai, Edward Chang, Erika Kirgios, Katherine L. Milkman (2024), Group Size and Its Impact on Diversity-Related Perceptions and Hiring Decisions in Homogeneous Groups, Organizational Science. https://doi.org/10.1287/orsc.2020.14705 Abstract

    Why do some homogeneous groups face backlash for lacking diversity, whereas others escape censure? We show that a homogeneous group’s size changes how it is perceived and whether decision makers pursue greater diversity in its ranks. We theorize that people make different inferences about larger groups than smaller ones—with consequences for diversity management—due to Bayesian reasoning. This can produce sensitivity to a lack of diversity in large groups and limited sensitivity to a lack of diversity in small groups. Because each group member represents the outcome of a hiring decision, larger homogeneous groups signal a diversity problem more strongly than smaller homogeneous groups. Across three preregistered experiments (n = 4,283), we show that decision makers are more likely to diversify larger homogeneous groups than smaller ones and view larger homogeneous groups as (i) more likely to have resulted from an unfair selection process; (ii) less diverse; (iii) more likely to face diversity-related impression management concerns; and (iv) less open to the influence of newly added underrepresented members. Further, (i)–(iii) mediate the relationship between homogeneous group size and decisions to diversify. We extend our findings to S&P 1500 corporate boards, showing that larger homogeneous boards are more likely to add women or racial minorities as directors. Larger homogeneous boards are also rarer than expected, whereas smaller homogeneous boards are surprisingly abundant. This suggests that decision makers neglect homogeneity in smaller groups, while investing extra effort toward diversifying larger homogeneous groups. Our findings highlight how group size shapes diversity-related perceptions and decisions and identify mechanisms that kickstart diversification efforts.

  • Rachel Gershon, Cynthia Cryder, Katherine L. Milkman (2024), Friends with Health Benefits: A Field Experiment, Management Science. https://doi.org/10.1287/mnsc.2022.01401 Abstract

    When pursuing goals, we commonly choose between going it alone versus teaming up together. In a field experiment (n = 774), we tested the benefits of rewarding individual versus tandem goal pursuit. In a standard-reward condition, we experimentally offered gym members an individual cash reward each day they visited the gym for four weeks. Participants in a tandem-reward condition could earn the same reward but only if they surmounted an extra logistical hurdle: they had to visit the gym with a friend. Although this additional requirement made it more difficult for participants in the tandem-reward condition to earn equivalent incentives, participants with this extra hurdle visited the gym about 35% more frequently than those earning a standard reward. A follow-up survey suggests that tandem rewards provide nonmonetary incentives that change behavior, including increased accountability and enjoyment. Our findings illustrate the advantages of making desired behaviors social to promote follow-through.

  • Kai Ruggeri, Friederike Stock, S. Alexander Haslam, Valerio Capraro, Paulo Boggio, Naomi Ellemers, Aleksandra Cichoka, Karen M. Douglas, David Rand, Sander van der Linden, Mina Cikara, Eli J. Finkel, James N. Druckman, Michael J.A. Wohl, Richard E. Petty, Joshua A. Tucker, Azim Shariff, Michele Gelfand, Dominic Packer, Jolanda Jetten, Paul A.M. Van Lange, Gordon Pennycook, Ellen Peters, Katherine Biacker, Alia Crum, Kim A. Weeden, Lucy Napper, Nassim Tabri, Jamil Zaki, Linda Skitka, Shinobu Kitayama, Dean Mobbs, Cass R. Sunstein, Sarah Ashcroft-Jones, Anna L. Todsen, Ali Hajian, Sanne Verra, Vanessa Buehler, Maja Friedemann, Marlene Hecht, Rayyan S. Mobarak, Ralitsa Karakasheva, Markus R. Tunte, Siu Kit Yeung, R. Shayna Rosenbaum, Zan Lep, Yuki Yamada, Sa-kiera T.J. Hudson, Lucia Macchia, Irina Soboleva, Eugen Dimant, Sandra J. Geiger, Hannes Jarke, Tobias Wingen, Jana B. Berkessel, Silvana Mareva, Lucy McGill, Francesca Papa, Bojana Veckalov, Zeina Afif, Eike K. Buabang, Marna Landman, Felice Tavera, Jack L. Andrews, Asli Burgalioglu, Zorana Zupan, Lisa Wagner, Joaquin Navajas, Marek Vranka, David Kasdan, Patricia Chen, Kathleen R. Hudson, Lindsay M. Novak, Paul Teas, Nikolay R. Rachev, Matteo M. Galizzi, Marija Petrovic, Katherine L. Milkman, Jay J. Van Bavel, Robb Willer (2023), A Synthesis of Evidence for Policy From Behavioural Science During COVID-19, Nature. https://doi.org/10.1038/s41586-023-06840-9 Abstract

    Scientific evidence regularly guides policy decisions, with behavioural science increasingly part of this process. In April 2020, an influential paper proposed 19 policy recommendations (‘claims’) detailing how evidence from behavioural science could contribute to efforts to reduce impacts and end the COVID-19 pandemic. Here we assess 747 pandemic-related research articles that empirically investigated those claims. We report the scale of evidence and whether evidence supports them to indicate applicability for policymaking. Two independent teams, involving 72 reviewers, found evidence for 18 of 19 claims, with both teams finding evidence supporting 16 (89%) of those 18 claims. The strongest evidence supported claims that anticipated culture, polarization and misinformation would be associated with policy effectiveness. Claims suggesting trusted leaders and positive social norms increased adherence to behavioural interventions also had strong empirical support, as did appealing to social consensus or bipartisan agreement. Targeted language in messaging yielded mixed effects and there were no effects for highlighting individual benefits or protecting others. No available evidence existed to assess any distinct differences in effects between using the terms ‘physical distancing’ and ‘social distancing’. Analysis of 463 papers containing data showed generally large samples; 418 involved human participants with a mean of 16,848 (median of 1,699). That statistical power underscored improved suitability of behavioural science research for informing policy decisions. Furthermore, by implementing a standardized approach to evidence selection and synthesis, we amplify broader implications for advancing scientific evidence in policy formulation and prioritization.

  • Anastasia Buyalskaya, Hung Ho, Katherine L. Milkman, Xiaomen Li, Angela Duckworth, Colin Camerer (2023), What Can Machine Learning Teach Us about Habit Formation? Evidence from Exercise and Hygiene, Proceedings of the National Academy of Sciences. https://doi.org/10.1073/pnas.2216115120 Abstract

    We apply a machine learning technique to characterize habit formation in two large panel data sets with objective measures of 1) gym attendance (over 12 million observations) and 2) hospital handwashing (over 40 million observations). Our Predicting Context Sensitivity (PCS) approach identifies context variables that best predict behavior for each individual. This approach also creates a time series of overall predictability for each individual. These time series predictability values are used to trace a habit formation curve for each individual, operationalizing the time of habit formation as the asymptotic limit of when behavior becomes highly predictable. Contrary to the popular belief in a “magic number” of days to develop a habit, we find that it typically takes months to form the habit of going to the gym but weeks to develop the habit of handwashing in the hospital. Furthermore, we find that gymgoers who are more predictable are less responsive to an intervention designed to promote more gym attendance, consistent with past experiments showing that habit formation generates insensitivity to reward devaluation.

  • Joseph Reiff, Hengchen Dai, John Beshears, Katherine L. Milkman, Shlomo Benartzi (2023), Save More Today or Tomorrow: The Role of Urgency in Precommitment Design, Journal of Marketing Research. https://doi.org/10.1177/00222437231153396 Abstract

    To encourage farsighted behaviors, previous research suggests that marketers should invite consumers to precommit to adopting these behaviors “later.” However, the authors propose that people will draw different inferences from different types of precommitment offers, and that these inferences can help explain when precommitment is (and is not) effective at increasing adoption of farsighted behaviors. Specifically, the authors theorize that simultaneously offering consumers the opportunity to adopt a farsighted behavior now or later (i.e., offering “simultaneous precommitment”) may signal that the behavior is not urgently recommended; however, offering consumers the opportunity to adopt that behavior immediately and then, only if they decline, inviting them to adopt it later (i.e., offering “sequential precommitment”) may signal just the opposite. In a multisite field experiment (N = 5,196), the authors find that simultaneously giving consumers the chance to increase their savings now or later reduced retirement savings. Two preregistered lab studies (N = 5,080) show that simultaneous precommitment leads people to infer that taking action is not urgently recommended, and such inferences predict less adoption of recommended behaviors. Importantly, offering sequential precommitment increases inferred urgency, predicting greater adoption. Together, this research advances knowledge about the limits and potential of precommitment.

  • Angela Duckworth and Katherine L. Milkman (2022), A Guide to Megastudies, Proceedings of the National Academy of Sciences Nexus. https://doi.org/10.1093/pnasnexus/pgac214 Abstract

    How can behavioral insights best be leveraged to solve pressing policy challenges? Because research studies are typically designed to test the validity of a particular idea, surprisingly little is known about the relative efficacy of different approaches to changing behavior in any given policy context. We discuss megastudies as a research approach that can surmount this and other obstacles to developing optimal behaviorally informed policy interventions. We define a megastudy as “a massive field experiment in which many different treatments are tested synchronously in one large sample using a common, objectively measured outcome.” We summarize this apples-to-apples approach to research and lay out recommendations, limitations, and promising future directions for scholars who might want to conduct or evaluate megastudies.

  • Aneesh Rai, Marissa A. Sharif, Edward H. Chang, Katherine L. Milkman, Angela Duckworth (2022), A Field Experiment on Subgoal Framing to Boost Volunteering: The Trade- Off Between Goal Granularity and Flexibility, Journal of Applied Psychology. https://doi.org/10.1037/apl0001040 Abstract

    Research suggests that breaking overarching goals into more granular subgoals is beneficial for goal progress. However, making goals more granular often involves reducing the flexibility provided to complete them, and recent work shows that flexibility can also be beneficial for goal pursuit. We examine this trade-off between granularity and flexibility in subgoals in a preregistered, large-scale field experiment (N = 9,108) conducted over several months with volunteers at a national crisis counseling organization. A preregistered vignette pilot study (N = 900) suggests that the subgoal framing tested in the field could benefit goal seekers by bolstering their self-efficacy and goal commitment, and by discouraging procrastination. Our field experiment finds that reframing an overarching goal of 200 hr of volunteering into more granular subgoals (either 4 hr of volunteering every week or 8 hr every 2 weeks) increased hours volunteered by 8% over a 12-week period. Further, increasing subgoal flexibility by breaking an annual 200-hr volunteering goal into a subgoal of volunteering 8 hr every 2 weeks, rather than 4 hr every week, led to more durable benefits.

  • All Research from Katherine L. Milkman »

Teaching

Current Courses

  • OIDD9950 - Dissertation Preparation

    OIDD9950025 ( Syllabus )

    OIDD9950026 ( Syllabus )

    OIDD9950029 ( Syllabus )

  • OIDD9999 - Independent Study

    Independent Study

    OIDD9999001 ( Syllabus )

    OIDD9999002 ( Syllabus )

Past Courses

  • MGMT6900 - Manag Decsn Making

    The course is built around lectures reviewing multiple empirical studies, class discussion,and a few cases. Depending on the instructor, grading is determined by some combination of short written assignments, tests, class participation and a final project (see each instructor's syllabus for details).

  • OIDD2900 - Decision Processes

    This course is an intensive introduction to various scientific perspectives on the processes through which people make decisions. Perspectives covered include cognitive psychology of human problem-solving, judgment and choice, theories of rational judgment and decision, and the mathematical theory of games. Much of the material is technically rigorous. Prior or current enrollment in STAT 101 or the equivalent, although not required, is strongly recommended.

  • OIDD2990 - Judg & Dec Making Res Im

    This class provides a high-level introduction to the field of judgment and decision making (JDM) and in-depth exposure to the process of doing research in this area. Throughout the semester you will gain hands-on experience with several different JDM research projects. You will be paired with a PhD student or faculty mentor who is working on a variety of different research studies. Each week you will be given assignments that are central to one or more of these studies, and you will be given detailed descriptions of the research projects you are contributing to and how your assignments relate to the successful completion of these projects. To complement your hands-on research experience, throughout the semester you will be assigned readings from the book Nudge by Thaler and Sunstein, which summarizes key recent ideas in the JDM literature. You will also meet as a group for an hour once every three weeks with the class's faculty supervisor and all of his or her PhD students to discuss the projects you are working on, to discuss the class readings, and to discuss your own research ideas stimulated by getting involved in various projects. Date and time to be mutually agreed upon by supervising faculty and students. the 1CU version of this course will involve approx. 10 hours of research immersion per week and a 10-page paper. The 0.5 CU version of this course will involve approx 5 hours of research immersion per week and a 5-page final paper. Please contact Professor Joseph Simmons if you are interested in enrolling in the course: jsimmo@wharton.upenn.edu

  • OIDD4900 - Sci of Behavior Change

    The objective of this 14-week discussion-based seminar for advanced undergraduates is to expose students to cutting-edge research from psychology and economics on the most effective strategies for changing behavior sustainably and for the better (e.g., promoting healthier eating and exercise, encouraging better study habits, and increasing savings rates). The weekly readings cover classic and current research in this area. The target audience for this course is advanced undergraduate students interested in behavioral science research and particularly those hoping to learn about using social science to change behavior for good. Although there are no pre-requisites for this class, it is well-suited to students who have taken (and enjoyed) courses like OIDD 2900: Decision Processes, PPE 2030/PSYC 2650: Behavioral Economics and Psychology, and MKTG 2660: Marketing for Social Impact and are interested in taking a deeper dive into the academic research related to promoting behavior change for good. Instructor permission is required to enroll in this course. Please complete the application if interested in registering for this seminar: http://bit.ly/bcfg-class-2020. The application deadline is July 31, 2020. Prerequisite: Permission of instructor required.

  • OIDD6900 - Manag Decsn Making

    The course is built around lectures reviewing multiple empirical studies, class discussion,and a few cases. Depending on the instructor, grading is determined by some combination of short written assignments, tests, class participation and a final project (see each instructor's syllabus for details).

  • OIDD9890 - Topics in Oidd

    The specific content of this course varies form semester to semester, depending on student and faculty interests.

  • OIDD9999 - OIDD 9999

    Independent Study

  • PSYC4900 - Sci of Behavior Change

    The objective of this 14-week discussion-based seminar for advanced undergraduates is to expose students to cutting-edge research from psychology and economics on the most effective strategies for changing behavior sustainably and for the better (e.g., promoting healthier eating and exercise, encouraging better study habits, and increasing savings rates). The weekly readings cover classic and current research in this area. The target audience for this course is advanced undergraduate students interested in behavioral science research and particularly those hoping to learn about using social science to change behavior for good. Although there are no pre-requisites for this class, it is well-suited to students who have taken (and enjoyed) courses like OIDD 2900: Decision Processes, PPE 2030/PSYC 2650: Behavioral Economics and Psychology, and MKTG 2660: Marketing for Social Impact and are interested in taking a deeper dive into the academic research related to promoting behavior change for good. Instructor permission is required to enroll in this course. Please complete the application if interested in registering for this seminar: http://bit.ly/bcfg-class-2020. The application deadline is July 31, 2020. Prerequisite: Permission of instructor required.

Awards And Honors

  • Nicosia Award for Best Short Competitive Paper from the Association for Consumer Research, 2024
  • Thinkers50 Top 50 Management Thinker, 2023
  • 10 Year Impact Award from Sage Journals for 2012 Journal of Marketing Research Article, 2023
  • Schmidt Futures Innovation Fellow, 2022
  • Thinkers50 Strategy Award, 2021
  • Thinkers50 Top 50 Management Thinker, 2021
  • Named a Fellow of the Association for Psychological Science, 2020
  • The Robert B. Cialdini Prize from SPSP, 2020
  • Award for the Best 2019 Academy of Management Journal Article, 2020
  • Finalist for the Thinkers50 Radar Award, 2017
  • William F. O’Dell Award for the Most Impactful 2012 Journal of Marketing Research Article, 2017
  • Excellence in Teaching Award for the Undergraduate Division at Wharton, 2016
  • Finalist for the Anvil Award for the Most Outstanding MBA Teacher at Wharton, 2015
  • Elected Faculty Marshal for Wharton MBA Class of 2015, 2015
  • Excellence in Teaching Award for the Undergraduate Division at Wharton, 2015
  • Society for Judgment and Decision Making FABBS Early Career Award Winner, 2015
  • Marketing Science Institute Young Scholar, 2015
  • SSRN Honor: Author of One of the 10 Most Downloaded Papers of the Year, 2014
  • Finalist for the Anvil Award for the Most Outstanding MBA Teacher at Wharton, 2014
  • Finalist for the Paul E. Green Award for the Best 2012 Journal of Marketing Research Article, 2013
  • Voted Winner of the Wharton “Iron Prof” Competition, 2013
  • Dorinda and Mark Winkelman Distinguished Scholar Award, 2012
  • Poets & Quants Selection: “World’s Best 40 B-School Professors under the Age of 40”, 2011
  • The Wyss Award from Harvard Business School for Excellence in Doctoral Research, 2008
  • The Lore von Jaskowsky Memorial Prize in Engineering from Princeton University, 2004
  • The Willard Thorp Thesis Prize in American Studies from Princeton University, 2004
  • Omega Rho Undergraduate Project Research Award from INFORMS, 2004

In the News

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Activity

Latest Research

Jose A. Cervantez and Katherine L. Milkman (2024), Can Nudges Be Leveraged to Enhance Diversity in Organizations? A Systematic Review, Current Opinion in Psychology. https://doi.org/10.1016/j.copsyc.2024.101874
All Research

In the News

Overwhelmed by Too Many Choices When Shopping? Wharton Retail Expert Weighs In

Wharton retail expert discusses why shoppers may feel overwhelmed when faced with many options.…Read More

Knowledge @ Wharton - 2024/12/19
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Awards and Honors

Nicosia Award for Best Short Competitive Paper from the Association for Consumer Research 2024
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