@article{dur_morrill_phan_2024, title={Partitionable choice functions and stability}, ISSN={["1432-217X"]}, DOI={10.1007/s00355-024-01534-1}, journal={SOCIAL CHOICE AND WELFARE}, author={Dur, Umut and Morrill, Thayer and Phan, William}, year={2024}, month={Jul} }
 @article{morrill_roth_2024, title={Top trading cycles}, volume={112}, ISSN={["1873-1538"]}, DOI={10.1016/j.jmateco.2024.102984}, journal={JOURNAL OF MATHEMATICAL ECONOMICS}, author={Morrill, Thayer and Roth, Alvin E.}, year={2024}, month={Jun} }
 @article{manjunath_morrill_2023, title={Interview hoarding}, volume={18}, ISSN={["1555-7561"]}, DOI={10.3982/TE4866}, abstractNote={Many centralized matching markets are preceded by interviews between participants, including the residency matches between doctors and hospitals. Due to the COVID‐19 pandemic, interviews in the National Resident Matching Program were switched to a virtual format, which resulted in a dramatic and asymmetric decrease in the cost of accepting interview invitations. We study the impact of an increase in the number of doctors' interviews on their final matches. We show analytically that if doctors can accept more interviews, but hospitals do not increase the number of interviews they offer, then no doctor who would have matched in the setting with more limited interviews is better off and many doctors are potentially harmed. This adverse effect is the result of what we call 
            interview hoarding. We characterize optimal mitigation strategies for special cases and use simulations to extend these insights to more general settings.
          }, number={2}, journal={THEORETICAL ECONOMICS}, author={Manjunath, Vikram and Morrill, Thayer}, year={2023}, month={May}, pages={503–527} }
 @article{dur_morrill_phan_2022, title={Family ties: School assignment with siblings}, volume={17}, ISSN={["1555-7561"]}, DOI={10.3982/TE4086}, abstractNote={We introduce a generalization of the school choice problem motivated by the following observations: students are assigned to grades within schools, many students have siblings who are applying as well, and school districts commonly guarantee that siblings will attend the same school. This last condition disqualifies the standard approach of considering grades independently as it may separate siblings. We argue that the central criterion in school choice—elimination of justified envy—is now inadequate as it does not consider siblings. We propose a new solution concept, 
            suitability, that addresses this concern, and we introduce a new family of 
            strategy‐proof mechanisms where each satisfies it. Using data from the Wake County magnet school assignment, we demonstrate the impact on families of our proposed mechanism versus the “naive” assignment where sibling constraints are not taken into account.
          }, number={1}, journal={THEORETICAL ECONOMICS}, author={Dur, Umut and Morrill, Thayer and Phan, William}, year={2022}, month={Jan}, pages={89–120} }
 @article{bichler_hammerl_morrill_waldherr_2021, title={How to Assign Scarce Resources Without Money: Designing Information Systems that Are Efficient, Truthful, and (Pretty) Fair}, volume={32}, ISSN={["1526-5536"]}, DOI={10.1287/isre.2020.0959}, abstractNote={ Matching with preferences has great potential to coordinate the efficient allocation of scarce resources in organizations when monetary transfers are not available. It is well known that it is impossible to combine all three properties of truthfulness, efficiency, and fairness (i.e., envy freeness) in matching with preferences. Established mechanisms are either efficient or envy free, and the efficiency loss in envy-free mechanisms is substantial. We focus on a widespread representative of a matching problem: course assignment where students have preferences for courses and organizers have priorities over students. An important feature in course assignment is that a course has a maximum capacity and a minimum required quota. This is also a requirement in many other matching applications, such as school choice, hospital-residents matching, or the assignment of workers to jobs. We introduce RESPCT, a mechanism that respects minimum quotas and is truthful, efficient, and has low levels of envy. The reduction in envy is significant and is due to two remarkably effective heuristics. We provide analytical and experimental results based on field data from a large-scale course assignment application. These results have led to a policy change and the proposed assignment system is now being used to match hundreds of students every semester. }, number={2}, journal={INFORMATION SYSTEMS RESEARCH}, author={Bichler, Martin and Hammerl, Alexander and Morrill, Thayer and Waldherr, Stefan}, year={2021}, month={Jun}, pages={335–355} }
 @article{ehlers_morrill_2020, title={(Il)legal Assignments in School Choice}, volume={87}, ISSN={["1467-937X"]}, DOI={10.1093/restud/rdz041}, abstractNote={Abstract
               In public school choice, students with strict preferences are assigned to schools. Schools are endowed with priorities over students. Incorporating constraints from different applications, priorities are often modelled as choice functions over sets of students. It has been argued that the most desirable criterion for an assignment is stability; there should not exist any blocking pair: no student shall prefer some school to her assigned school and have higher priority than some student who got into that school or the school has an empty seat. We propose a blocking notion where in addition it must be possible to assign the student to her preferred school. We then define the following stability criterion for a set of assignments: a set of assignments is legal if and only if any assignment outside the set is blocked with some assignment in the set and no two assignments inside the set block each other. We show that under very basic conditions on priorities, there always exists a unique legal set of assignments, and that this set has a structure common to the set of stable assignments: (i) it is a lattice and (ii) it satisfies the rural hospitals theorem. The student-optimal legal assignment is efficient and provides a solution for the conflict between stability and efficiency.}, number={4}, journal={REVIEW OF ECONOMIC STUDIES}, author={Ehlers, Lars and Morrill, Thayer}, year={2020}, month={Jul}, pages={1837–1875} }
 @article{troyan_morrill_2019, title={Obvious Manipulations}, DOI={10.1145/3328526.3329640}, abstractNote={A mechanism is strategy-proof if agents can never profitably manipulate, in any state of the world; however, not all non-strategy-proof mechanisms are equally easy to manipulate - some are more "obviously'' manipulable than others. We propose a formal definition of an obvious manipulation and argue that it may be advantageous for designers to tolerate some manipulations, so long as they are non-obvious. By doing so, improvements can be achieved on other key dimensions, such as efficiency and fairness, without significantly compromising incentives. We classify common non-strategy-proof mechanisms as either obviously manipulable (OM) or not obviously manipulable (NOM), and show that this distinction is both tractable and in-line with empirical realities regarding the success of manipulable mechanisms in practical market design settings.}, journal={ACM EC '19: PROCEEDINGS OF THE 2019 ACM CONFERENCE ON ECONOMICS AND COMPUTATION}, author={Troyan, Peter and Morrill, Thayer}, year={2019}, pages={865–865} }
 @article{troyan_morrill_2020, title={Obvious manipulations}, volume={185}, ISSN={["1095-7235"]}, DOI={10.1016/j.jet.2019.104970}, abstractNote={A mechanism is strategy-proof if agents can never profitably manipulate it, in any state of the world; however, not all non-strategy-proof mechanisms are equally easy to manipulate - some are more "obviously" manipulable than others. We propose a formal definition of an obvious manipulation in which agents compare worst cases to worst cases and best cases to best cases. We show that a profitable manipulation is obvious if and only if it can be identified as profitable by a cognitively limited agent who is unable to engage in contingent reasoning, as in Li (2017). Finally, we show that this system of categorization is both tractable and intuitively appealing by classifying common non-strategy-proof mechanisms as either obviously manipulable (OM) or not obviously manipulable (NOM).}, journal={JOURNAL OF ECONOMIC THEORY}, author={Troyan, Peter and Morrill, Thayer}, year={2020}, month={Jan} }
 @article{dur_hammond_morrill_2018, title={Identifying the Harm of Manipulable School-Choice Mechanisms}, volume={10}, ISSN={["1945-774X"]}, DOI={10.1257/pol.20160132}, abstractNote={ An important but under-explored issue in student assignment procedures is heterogeneity in the level of strategic sophistication among students. Our work provides the first direct measure of which students rank schools following their true preference order (sincere students) and which rank schools by manipulating their true preferences (sophisticated students). We present evidence that our proxy for sophistication captures systematic differences among students. Our results demonstrate that sophisticated students are 9.6 percentage points more likely to be assigned to one of their preferred schools. Further, we show that this large difference in assignment probability occurs because sophisticated students systematically avoid over-demanded schools. (JEL D82, H75, I21, I28) }, number={1}, journal={AMERICAN ECONOMIC JOURNAL-ECONOMIC POLICY}, author={Dur, Umut and Hammond, Robert G. and Morrill, Thayer}, year={2018}, month={Feb}, pages={187–213} }
 @article{dur_hammond_morrill_2019, title={The Secure Boston Mechanism: theory and experiments}, volume={22}, ISSN={["1573-6938"]}, DOI={10.1007/s10683-018-9594-z}, number={4}, journal={EXPERIMENTAL ECONOMICS}, author={Dur, Umut and Hammond, Robert G. and Morrill, Thayer}, year={2019}, month={Dec}, pages={918–953} }
 @article{dur_morrill_2018, title={Competitive equilibria in school assignment}, volume={108}, ISSN={0899-8256}, url={http://dx.doi.org/10.1016/J.GEB.2017.10.003}, DOI={10.1016/J.GEB.2017.10.003}, abstractNote={Top Trading Cycles was originally developed as an elegant method for finding a competitive equilibrium of Shapley and Scarf's housing market. We extend the definition of a competitive equilibrium to the school assignment problem and show that there remains a profound relationship between Top Trading Cycles and a competitive equilibrium. Specifically, in every competitive equilibrium with weakly decreasing prices, the equilibrium assignment is unique and exactly corresponds to the Top Trading Cycles assignment. This provides a new way of interpreting the worth of a student's priority at a given school. It also provides a new way of explaining Top Trading Cycles to students and a school board.}, journal={Games and Economic Behavior}, publisher={Elsevier BV}, author={Dur, Umut and Morrill, Thayer}, year={2018}, month={Mar}, pages={269–274} }
 @article{baranov_aperjis_ausubel_morrill_2017, title={Efficient Procurement Auctions with Increasing Returns}, volume={9}, ISSN={["1945-7685"]}, DOI={10.1257/mic.20160087}, abstractNote={ For procuring from sellers with decreasing returns, there are known efficient dynamic auction formats. In this paper, we design an efficient dynamic procurement auction for the case where goods are homogeneous and bidders have increasing returns. Our motivating example is the procurement of vaccines, which often exhibit large fixed costs and small constant marginal costs. The auctioneer names a price and bidders report the interval of quantities that they are willing to sell at that price. The process repeats with successively lower prices, until the efficient outcome is discovered. We demonstrate an equilibrium that is efficient and generates VCG prices. (JEL D24, D44, F53, H57, I11, L14, L65) }, number={3}, journal={AMERICAN ECONOMIC JOURNAL-MICROECONOMICS}, author={Baranov, Oleg and Aperjis, Christina and Ausubel, Lawrence M. and Morrill, Thayer}, year={2017}, month={Aug}, pages={1–27} }
 @article{hammond_morrill_2016, title={Personality traits and bidding behavior in competing auctions}, volume={57}, ISSN={["1872-7719"]}, DOI={10.1016/j.joep.2016.08.005}, abstractNote={We study strategic behavior in an "alternating recognition" model of English auctions with competing sellers, which mimics a structure that is common in online marketplaces such as eBay. To relate decision making in our experimental setting to individual differences, we measure subjects' personality with the Big-Five Trait Taxonomy. Our results suggest that personality has meaningful predictive power in explaining bidding behavior but only for female subjects. Further, females also earn more than males and the gender gap in earnings is large and significant. Finally, personality indirectly affects earnings through the choice of strategies but has no direct effect on earnings, controlling for strategies. This is an important result in that it demonstrates the mechanism through which personality matters in our setting.}, journal={JOURNAL OF ECONOMIC PSYCHOLOGY}, author={Hammond, Robert G. and Morrill, Thayer}, year={2016}, month={Dec}, pages={39–55} }
 @article{morrill_2016, title={Petty Envy When Assigning Objects}, DOI={10.1145/2940716.2940718}, abstractNote={Envy of another person's assignment is ``justified'' if you ``deserve'' the object and it is possible to assign you to the object. Currently, the literature only considers whether or not the agent deserves the object and ignores whether or not assigning her to it is possible. This paper defines a fair set of assignments in terms of what is possible. We prove that a fair set of assignments has the same properties as the set of stable matches: the Lattice Theorem, Decomposition Lemma, and Rural Hospital Theorem all hold. Moreover, there is a unique, student-optimal fair assignment: the assignment made by Kesten's Efficiency Adjusted Deferred Acceptance mechanism when all students consent.}, journal={EC'16: PROCEEDINGS OF THE 2016 ACM CONFERENCE ON ECONOMICS AND COMPUTATION}, author={Morrill, Thayer}, year={2016}, pages={761–761} }
 @article{morrill_2015, title={Making just school assignments}, volume={92}, ISSN={["1090-2473"]}, DOI={10.1016/j.geb.2015.05.004}, abstractNote={It is impossible for a mechanism to be strategyproof, Pareto efficient, and eliminate justified envy. However, little is known to what extent a strategyproof and efficient mechanism can limit justified envy. We define an assignment to be unjust if a student i is not assigned to a school a that she prefers to her own assignment, i has higher priority at a than some student j who is assigned to a, and none of the students ranked higher at a than i are dependent on j. We prove that Top Trading Cycles is the unique mechanism that is strategyproof, efficient, and just. This demonstrates that a strictly stronger notion of fairness than justness is either unachievable by a strategyproof and efficient mechanism or it is only achievable by TTC. We extend this characterization to the general case when schools may have arbitrary capacities by introducing the concept of reducibility.}, journal={GAMES AND ECONOMIC BEHAVIOR}, author={Morrill, Thayer}, year={2015}, month={Jul}, pages={18–27} }
 @article{hammond_morrill_2014, title={STRATEGIC EXCLUSION OF THE HIGHEST-VALUED BIDDERS IN WHOLESALE AUTOMOBILE AUCTIONS}, volume={52}, ISSN={["1465-7295"]}, DOI={10.1111/ecin.12078}, abstractNote={By restricting bidders to be qualified dealers, wholesale automobile auctions exclude the bidders who place the highest value on the vehicles: consumers. This article provides an explanation for this puzzling entry restriction by modeling the inventory‐management decisions of a firm. If an automobile dealer has more vehicles in inventory than is optimal, it cannot reduce its inventory by selling directly to consumers without impacting the demand for the automobiles that remain. However, if the dealer sells his/her excess inventory to a competitor, the demand for his/her remaining vehicles increases as the competitor responds by acquiring fewer additional vehicles. We demonstrate that for any market demand function and any cost of the competitor acquiring additional vehicles, a dealer with excess inventory does better by selling a subset of its vehicles to a competitor rather than directly to consumers. We discuss the market for wholesale automobiles in relation to other markets where goods are also auctioned but where entry is not restricted to qualified dealers. Doing so allows us to compare our inventory‐management explanation to common explanations provided by industry practitioners. We find that intuitive alternative stories do not consistently explain practices across markets. (JEL D44, L11, L62)}, number={3}, journal={ECONOMIC INQUIRY}, author={Hammond, Robert G. and Morrill, Thayer}, year={2014}, month={Jul}, pages={1219–1230} }
 @article{ausubel_morrill_2014, title={Sequential Kidney Exchange}, volume={6}, ISSN={["1945-7685"]}, DOI={10.1257/mic.6.3.265}, abstractNote={ The traditional literature on kidney exchange assumes that all components of the exchange must occur simultaneously. Unfortunately, the number of operating rooms required for concurrent surgeries poses a significant constraint on the beneficial exchanges that may be attained. The basic insight of this paper is that incentive compatibility does not require simultaneous exchange; rather, it requires that organ donation occurs no later than the associated organ receipt. Using sequential exchanges may relax the operating room constraint and thereby increase the number of beneficial exchanges. We show that most benefits of sequential exchange can be accomplished with only two concurrent operating rooms. (JEL D47, I11) }, number={3}, journal={AMERICAN ECONOMIC JOURNAL-MICROECONOMICS}, author={Ausubel, Lawrence M. and Morrill, Thayer}, year={2014}, month={Aug}, pages={265–285} }
 @article{morrill_2015, title={Two simple variations of top trading cycles}, volume={60}, ISSN={["1432-0479"]}, DOI={10.1007/s00199-014-0820-4}, number={1}, journal={ECONOMIC THEORY}, author={Morrill, Thayer}, year={2015}, month={Sep}, pages={123–140} }
 @article{morrill_2013, title={An alternative characterization of top trading cycles}, volume={54}, ISSN={["0938-2259"]}, DOI={10.1007/s00199-012-0713-3}, number={1}, journal={ECONOMIC THEORY}, author={Morrill, Thayer}, year={2013}, month={Sep}, pages={181–197} }
 @article{morrill_morrill_2013, title={Intergenerational links in female labor force participation}, volume={20}, ISSN={["1879-1034"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84873129190&partnerID=MN8TOARS}, DOI={10.1016/j.labeco.2012.10.002}, abstractNote={Fernandez, Fogli, and Olivetti (2004) introduce an innovative model of how the experiences of one generation of women affect the behavior of the next generation of women via their sons/husbands. Empirically they find that a woman is more likely to work if her mother-in-law worked than if her own mother worked. We confirm this intriguing result but demonstrate that there is also a link between the labor force participation choices of mothers and daughters. Further, in an alternative theoretical model we show that the relationship between the labor force participation of mothers-in-law and daughters-in-law may be due instead to a woman's own preferences formed before selecting a spouse. Interestingly, the model demonstrates that the correlation in labor force status may be stronger for a mother-in-law/daughter-in-law pair than a mother/daughter pair, even if the preference formation channel is solely from mothers to daughters.}, journal={LABOUR ECONOMICS}, author={Morrill, Melinda Sandler and Morrill, Thayer}, year={2013}, month={Jan}, pages={38–47} }
 @article{morrill_2013, title={An alternative characterization of the deferred acceptance algorithm}, volume={42}, ISSN={["1432-1270"]}, DOI={10.1007/s00182-011-0311-9}, number={1}, journal={INTERNATIONAL JOURNAL OF GAME THEORY}, author={Morrill, Thayer}, year={2013}, month={Feb}, pages={19–28} }
 @article{morrill_2011, title={Network formation under negative degree-based externalities}, volume={40}, ISSN={["1432-1270"]}, DOI={10.1007/s00182-010-0256-4}, number={2}, journal={INTERNATIONAL JOURNAL OF GAME THEORY}, author={Morrill, Thayer}, year={2011}, month={May}, pages={367–385} }
 @article{morrill_2010, title={The roommates problem revisited}, volume={145}, ISSN={["1095-7235"]}, DOI={10.1016/j.jet.2010.02.003}, abstractNote={One of the oldest matching problems is Gale and Shapley's (1962) [8] “roommates problem”: is there a stable way to assign 2N students into N roommate pairs? Unlike the classic marriage problem or college admissions problem, there need not exist a stable solution to the roommates problem. However, stability ignores the key physical constraint that roommates require a room and is therefore too restrictive. This motivates a new matching problem: matching agents subject to an initial assignment. A particularly important example is kidney exchange where after an assignment has been made, subsequent tests may determine that a patient and donor are incompatible. This paper introduces an efficient algorithm for finding a Pareto improvement starting from any status quo roommates assignment.}, number={5}, journal={JOURNAL OF ECONOMIC THEORY}, author={Morrill, Thayer}, year={2010}, month={Sep}, pages={1739–1756} }