Katherine B. Coffman - Faculty & Research - Harvard Business School
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Katherine B. Coffman

Assistant Professor of Business Administration

Negotiation, Organizations & Markets

Katherine Coffman is an assistant professor of business administration in the Negotiations, Organizations & Markets unit. Before joining HBS, she was an assistant professor of economics at The Ohio State University and a visiting assistant professor of economics at Stanford University.

In her research, Professor Coffman uses experimental methods to study individual and group decision making, with a focus on gender issues. Her work has been published in Management Science, the Quarterly Journal of Economics, and Social Choice and Welfare, and it has been cited in such media outlets as Pew Research, the Los Angeles Times, Slate, The Atlantic, and Time. She is an associate editor of the Journal of the European Economic Association.

Professor Coffman holds a PhD in economics from Harvard University and a BA in mathematics and economics from Williams College.

Journal Articles
  1. Assent-maximizing Social Choice

    Katherine A. Baldiga and Jerry R. Green

    We take a decision theoretic approach to the classic social choice problem, using data on the frequency of choice problems to compute social choice functions. We define a family of social choice rules that depend on the population's preferences and on the probability distribution over the sets of feasible alternatives that the society will face. Our methods generalize the well-known Kemeny Rule. In the Kemeny Rule, it is known a priori that the subset of feasible alternatives will be a pair. We define a distinct social choice function for each distribution over the feasible subsets. Our rules can be interpreted as distance minimization—selecting the order closest to the population's preferences, using a metric on the orders that reflects the distribution over the possible feasible sets. The distance is the probability that two orders will disagree about the optimal choice from a randomly selected available set. We provide an algorithmic method to compute these metrics in the case where the probability of a given feasible set is a function only of its cardinality.

    Keywords: Decision Choices and Conditions; Theory; Measurement and Metrics; Mathematical Methods; Society;


    Baldiga, Katherine A., and Jerry R. Green. "Assent-maximizing Social Choice." Social Choice and Welfare 40, no. 2 (February 2013): 439–460.  View Details
  2. Representative Democracy and the Implementation of Majority-Preferred Alternatives

    Katherine Baldiga Coffman

    In this paper, we contrast direct and representative democracy. In a direct democracy, individuals have the opportunity to vote over the alternatives in every choice problem the population faces. In a representative democracy, the population commits to a candidate ex ante who will then make choices on its behalf. While direct democracy is normatively appealing, representative democracy is the far more common institution because of its practical advantages. The key question, then, is whether representative democracy succeeds in implementing the choices that the group would make under direct democracy. We find that, in general, it does not. We analyze the theoretical setting in which the two methods are most likely to lead to the same choices, minimizing potential sources of distortion. We model a population as a distribution of voters with strict preferences over a finite set of alternatives and a candidate as an ordering of those alternatives that serves as a binding, contingent plan of action. We focus on the case where the direct democracy choices of the population are consistent with an ordering of the alternatives. We show that even in this case, where the normative recommendation of direct democracy is clear, representative democracy may not elect the candidate with this ordering.

    Keywords: Economic Systems; Voting; Decision Choices and Conditions;


    Coffman, Katherine Baldiga. "Representative Democracy and the Implementation of Majority-Preferred Alternatives." Social Choice and Welfare 46, no. 3 (March 2016): 477–494.  View Details
  3. Laboratory Evidence on the Effects of Sponsorship on the Competitive Preferences of Men and Women

    Nancy R. Baldiga and Katherine Baldiga Coffman

    Sponsorship programs have been proposed as one way to promote female advancement in competitive career fields. A sponsor is someone who advocates for a protégé, and in doing so, takes a stake in her success. We use a laboratory experiment to explore two channels through which sponsorship has been posited to increase advancement in a competitive workplace. In our setting, being sponsored provides a vote of confidence and/or creates a link between the protégé’s and sponsor’s payoffs. We find that both features of sponsorship significantly increase willingness to compete among men on average, while neither of these channels significantly increases willingness to compete among women on average. As a result, sponsorship does not close the gender gap in competitiveness or earnings. We discuss how these insights from the laboratory could help to inform the design of sponsorship programs in the field.

    Keywords: economics; behavior and behavioral decision making; laboratory experiment; Competition; Organizations; Gender; Behavior;


    Baldiga, Nancy R., and Katherine Baldiga Coffman. "Laboratory Evidence on the Effects of Sponsorship on the Competitive Preferences of Men and Women." Management Science 64, no. 2 (February 2018): 888–901.  View Details
  4. The Size of the LGBT Population and the Magnitude of Anti-Gay Sentiment Are Substantially Underestimated

    Katherine Baldiga Coffman, Lucas C. Coffman and Keith M. Marzilli Ericson

    We demonstrate that widely used measures of anti-gay sentiment and the size of the LGBT population are misestimated, likely substantially. In a series of online experiments using a large and diverse but non-representative sample, we compare estimates from the standard methodology of asking sensitive questions to measures from a “veiled” methodology that precludes inference about an individual but provides population estimates. The veiled method increased self-reports of anti-gay sentiment, particularly in the workplace: respondents were 67% more likely to disapprove of an openly gay manager when asked with a veil, and 71% more likely to say it should be legal to discriminate in hiring on the basis of sexual orientation. The veiled methodology also produces larger estimates of the fraction of the population that identifies as LGBT or has had a sexual experience with a member of the same sex. Self-reports of non-heterosexual identity rose by 65%, and same-sex sexual experiences by 59%. We conduct a “placebo test” and show that for non-sensitive placebo items, the veiled methodology produces effects that are small in magnitude and not significantly different from zero in seven out of eight items. Taken together the results suggest anti-gay discrimination might be a more significant issue than formerly considered, as the non-heterosexual population and anti-gay workplace-related sentiment are both larger than previously measured.

    Keywords: LGBTQ; demographics; Social Trends & Culture; Economic Theory; Prejudice; Prejudice and Bias; Diversity; Economics; Demographics;


    Coffman, Katherine Baldiga, Lucas C. Coffman, and Keith M. Marzilli Ericson. "The Size of the LGBT Population and the Magnitude of Anti-Gay Sentiment Are Substantially Underestimated." Management Science 63, no. 10 (October 2017): 3168–3186.  View Details
  5. Stereotypes

    Pedro Bordalo, Katherine Baldiga Coffman, Nicola Gennaioli and Andrei Shleifer

    We present a model of stereotypes based on Kahneman and Tversky's representativeness heuristic. A decision maker assesses a target group by overweighting its representative types, which we formally define to be the types that occur more frequently in that group than in a baseline reference group. Stereotypes formed in this way contain a "kernel of truth": they are rooted in true differences between groups. They are also context dependent: beliefs about a group depend on the characteristics of the reference group. Because stereotypes emphasize differences, they cause belief distortions, particularly when groups are similar. In line with our predictions, beliefs in the lab about abstract groups and beliefs in the field about political groups are context dependent and distorted in the direction of representative types.

    Keywords: Prejudice and Bias;


    Bordalo, Pedro, Katherine Baldiga Coffman, Nicola Gennaioli, and Andrei Shleifer. "Stereotypes." Quarterly Journal of Economics 131, no. 4 (November 2016): 1753–1794.  View Details
  6. Gender Differences in Willingness to Guess

    Katherine Baldiga Coffman

    We present the results of an experiment that explores whether women are less willing than men to guess on multiple-choice tests. Our test consists of practice questions from SAT II subject tests; we vary whether a penalty is imposed for a wrong answer and the salience of the evaluative nature of the task. We find that when no penalty is assessed for a wrong answer, all test-takers answer every question. But, when there is a penalty for wrong answers, women answer significantly fewer questions than men. We see no differences in knowledge of the material or confidence in the test-takers, and differences in risk preferences explain less than half of the observed gap. Making the evaluative aspect of the test more salient does not impact the gender gap. We show that, conditional on their knowledge of the material, test-takers who skip questions do significantly worse on our test.

    Keywords: economics; behavior; behavioral decision making; microeconomic behavior; education systems; Behavior; Decision Choices and Conditions; Gender; Economics;


    Coffman, Katherine Baldiga. "Gender Differences in Willingness to Guess." Management Science 60, no. 2 (February 2014): 434–448.  View Details
  7. Evidence on Self-Stereotyping and the Contribution of Ideas

    Katherine Baldiga Coffman

    We use a lab experiment to explore the factors that predict an individual's decision to contribute her idea to a group. We find that contribution decisions depend upon the interaction of gender and the gender stereotype associated with the decision-making domain: conditional on measured ability, individuals are less willing to contribute ideas in areas that are stereotypically outside of their gender's domain. Importantly, these decisions are largely driven by self-assessments, rather than fear of discrimination. Individuals are less confident in gender incongruent areas and are thus less willing to contribute their ideas. Because even very knowledgeable group members under-contribute in gender incongruent categories, group performance suffers and, ex post, groups have difficulty recognizing who their most talented members are. Our results show that even in an environment where other group members show no bias, women in male-typed areas and men in female-typed areas may be less influential. An intervention that provides feedback about a woman's (man's) strength in a male-typed (female-typed) area does not significantly increase the probability that she contributes her ideas to the group. A back-of-the-envelope calculation reveals that a "lean in" style policy that increases contribution by women would significantly improve group performance in male-typed domains.

    Keywords: Groups and Teams; Decision Choices and Conditions; Organizations; Gender;


    Coffman, Katherine Baldiga. "Evidence on Self-Stereotyping and the Contribution of Ideas." Quarterly Journal of Economics 129, no. 4 (November 2014): 1625–1660.  View Details
Working Papers
  1. When Gender Discrimination Is Not About Gender

    Katherine B. Coffman, Christine L. Exley and Muriel Niederle

    We use an experiment to show that employers prefer to hire male over female workers for a male-typed task even when they have identical resumes. Using a novel control condition, we document that this discrimination is not specific to gender and is instead driven by beliefs. Employers are simply less willing to hire a worker from a group that performs worse on average, even when this group is instead defined by birth month, a non-stereotypical characteristic. A reluctance to discriminate emerges if workers share the gender or birth month of the worker from the worse-performing group, but even then, a small “excuse" counters this reluctance. Thus, our evidence points to an important role for beliefs in explaining gender discrimination.

    Keywords: Gender; Demographics; Attitudes; Prejudice and Bias;


    Coffman, Katherine B., Christine L. Exley, and Muriel Niederle. "When Gender Discrimination Is Not About Gender." Harvard Business School Working Paper, No. 18-054, December 2017. (Revised June 2018.)  View Details
  2. Beliefs about Gender

    Pedro Bordalo, Katherine Baldiga Coffman, Nicola Gennaioli and Andrei Shleifer

    We conduct a laboratory experiment on the determinants of beliefs about own and others’ ability across different domains. A preliminary look at the data points to two distinct forces: miscalibration in estimating performance depending on the difficulty of tasks and gender stereotypes. We develop a theoretical model that separates these forces and apply it to analyze a large laboratory dataset in which participants estimate their own and a partner’s performance on questions across six subjects: arts and literature, emotion recognition, business, verbal reasoning, mathematics, and sports. We find that participants greatly overestimate not only their own ability but also that of others, suggesting that miscalibration is a substantial, first order factor in stated beliefs. Women are better calibrated than men, providing more accurate estimates of ability both for themselves and for others. Gender stereotypes also have strong predictive power for beliefs, particularly for men’s beliefs about themselves and others’ beliefs about the ability of men. Our findings help interpret evidence on gender gaps in self-confidence.

    Keywords: Performance Evaluation; Perspective; Cognition and Thinking; Gender;


    Bordalo, Pedro, Katherine Baldiga Coffman, Nicola Gennaioli, and Andrei Shleifer. "Beliefs about Gender." Working Paper, December 2016.  View Details
  3. Experimental Evidence on Policies Aimed at Closing the Gender Gap in Willingness to Guess on Multiple-Choice Tests

    Katherine Baldiga Coffman

    Research has shown that women skip more questions than men on multiple-choice tests with penalties for wrong answers. We propose and test five policy changes aimed at eliminating this source of gender bias in test scores. Our data show that simply removing the penalty for wrong answers reduces the number of questions skipped by test-takers; however, in this treatment, women still skip more questions than men. We identify two other effective interventions, both of which maintain the standard scoring structure of multiple-choice tests (penalties for wrong answers), reduce the number of questions skipped by test-takers, and eliminate the gender gap.

    Keywords: Competition; Behavior; Decision Choices and Conditions; Gender;


    Coffman, Katherine Baldiga. "Experimental Evidence on Policies Aimed at Closing the Gender Gap in Willingness to Guess on Multiple-Choice Tests." Working Paper, August 2016.  View Details
Cases and Teaching Materials