@article{dur_zhang_2023, title={Fairness under affirmative action policies with overlapping reserves}, volume={109}, ISSN={["1873-1538"]}, DOI={10.1016/j.jmateco.2023.102907}, abstractNote={We study the allocation of homogeneous positions under affirmative action policies where some positions are reserved for underrepresented groups on a “minimum guarantee” basis. Each individual has a merit-based score and may be eligible for multiple reserves. When an individual counts towards each of the reserves that she is eligible for upon admission, we propose a choice function that satisfies three properties: the minimum guarantee requirement, non-wastefulness, and a stronger fairness notion than the one introduced by Sönmez and Yenmez (2019). Our proposed choice function is the unique one that produces an assignment achieving the maximal cutoff score in a recursive way among all non-wasteful assignments satisfying the minimum guarantee requirement. We show that the outcome of this choice function is not score-wise dominated by any other assignment that satisfies the minimum guarantee requirement.}, journal={JOURNAL OF MATHEMATICAL ECONOMICS}, author={Dur, Umut and Zhang, Yanning}, year={2023}, month={Dec} } @article{afacan_dur_2023, title={Strategy-proof size improvement: is it possible?}, ISSN={["1467-9442"]}, DOI={10.1111/sjoe.12515}, abstractNote={In unit-demand and multi-copy object allocation problems, we say that a mechanism size-wise dominates another mechanism if the latter never allocates more objects than the former does, while the converse is true for some problem. Our main result shows that no individually rational and strategy-proof mechanism size-wise dominates a non-wasteful, truncation-invariant, and extension-responding mechanism. As a corollary of this, the wellknown deferred-acceptance, serial dictatorship, and Boston mechanisms are not size-wise dominated by an individually rational and strategy-proof mechanism. We also show that whenever the number of agents does not exceed the total number of object copies, no group strategy-proof and ecient mechanism, such as top trading cycles mechanism, is size-wise dominated by an individually rational, weakly population-monotonic, and strategy-proof mechanism.}, journal={SCANDINAVIAN JOURNAL OF ECONOMICS}, author={Afacan, Mustafa Oguz and Dur, Umut}, year={2023}, month={Apr} } @article{dur_pathak_song_sonmez_2022, title={Deduction Dilemmas: The Taiwan Assignment Mechanism}, volume={14}, ISSN={["1945-7685"]}, DOI={10.1257/mic.20180386}, abstractNote={This paper analyzes the Taiwan mechanism used nationwide for high school assignment starting in 2014. In the Taiwan mechanism, points are deducted from an applicant’s score, with larger penalties for lower-ranked choices. Deduction makes the mechanism a hybrid of the Boston and deferred acceptance mechanisms. Our analysis sheds light on why Taiwan’s new mechanism has led to massive nationwide demonstrations and why it nonetheless remains in use. (JEL D47, I21, I28)}, number={1}, journal={AMERICAN ECONOMIC JOURNAL-MICROECONOMICS}, author={Dur, Umut and Pathak, Parag A. and Song, Fei and Sonmez, Tayfun}, year={2022}, month={Feb}, pages={164–185} } @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{dur_xie_2022, title={Responsiveness to priority-based affirmative action policy in school choice}, ISSN={["1467-9779"]}, DOI={10.1111/jpet.12605}, abstractNote={Abstract We consider the priority‐based affirmative action policy in school choice. We weaken the responsiveness to affirmative action policy by requiring at least one minority student to be weakly better off when their priorities are improved. We find that under both the student‐proposing deferred acceptance mechanism and the top trading cycles mechanism at least one minority student becomes weakly better off when their priorities are improved. We also strengthen the responsiveness to affirmative action policy by requiring all minority students to be weakly better off when their priorities are improved. We call this property strict responsiveness to affirmative action policy. We find that there is no nonwasteful, individually rational, mutually best, and strategy‐proof mechanism that is strictly responsive to affirmative action policy. We then find a sufficient condition for the affirmative action policy to satisfy for the student‐proposing deferred acceptance mechanism to be strictly responsive to affirmative action policy by setting restrictions on the priority improvements made by the policy.}, journal={JOURNAL OF PUBLIC ECONOMIC THEORY}, author={Dur, Umut and Xie, Yifan}, year={2022}, month={Jul} } @article{afacan_dur_harris_2021, title={School Choice with Hybrid Schedules}, volume={12}, ISSN={["2073-4336"]}, DOI={10.3390/g12020037}, abstractNote={During the pandemic, school districts have adopted hybrid schedules to continue the education of the students while maintaining social distance. In a hybrid schedule, students in the same classroom are usually divided into two groups and students only in the same group can physically attend class together two days a week. School districts do not take preferences of the students/parents over the days they would like to come to school into account during this procedure. In this paper, we propose a solution that divides students into groups based on their preferences. Our solution respects the number of classrooms initially reserved for each grade and enables possible efficiency gains by swapping classrooms across grades. Moreover, when there are two alternative schedules provided for students, our solution is immune to preference manipulations.}, number={2}, journal={GAMES}, author={Afacan, Mustafa Oguz and Dur, Umut and Harris, William}, year={2021}, month={Jun} } @article{dur_hammond_kesten_2021, title={Sequential school choice: Theory and evidence from the field and lab}, volume={198}, ISSN={["1095-7235"]}, DOI={10.1016/j.jet.2021.105344}, abstractNote={We analyze sequential preference submission in centralized matching problems. Our motivation comes from school districts and colleges that use an application website where students submit their preferences over schools sequentially, after learning information about previous submissions. Comparing the widely used Boston Mechanism (BM) to the celebrated Deferred Acceptance (DA) mechanism, we show that a sequential implementation of BM can achieve superior equilibrium outcomes relative to the student-optimal stable matching. Our empirical tests use data from the field and from a laboratory experiment. We find that sequential preference submission may allow students to overcome the coordination problem in school choice. Our findings may have important policy implications in numerous places across the world where BM is currently in use.}, journal={JOURNAL OF ECONOMIC THEORY}, author={Dur, Umut and Hammond, Robert G. and Kesten, Onur}, year={2021}, month={Dec} } @article{afacan_dur_2020, title={Constrained stability in two-sided matching markets}, volume={55}, ISSN={["1432-217X"]}, DOI={10.1007/s00355-020-01252-4}, number={3}, journal={SOCIAL CHOICE AND WELFARE}, author={Afacan, Mustafa Oguz and Dur, Umut Mert}, year={2020}, month={Oct}, pages={477–494} } @article{dur_pathak_sonmez_2020, title={Explicit vs. statistical targeting in affirmative action: Theory and evidence from Chicago's exam schools}, volume={187}, ISSN={["1095-7235"]}, DOI={10.1016/j.jet.2020.1049960022}, journal={JOURNAL OF ECONOMIC THEORY}, author={Dur, Umut and Pathak, Parag A. and Sonmez, Tayfun}, year={2020}, month={May} } @article{dur_gitmez_yilmaz_2019, title={School choice under partial fairness}, volume={14}, ISSN={["1555-7561"]}, DOI={10.3982/TE2482}, abstractNote={We generalize the school choice problem by defining a notion of allowable priority violations. In this setting, a weak axiom of stability (partial stability) allows only certain priority violations. We introduce a class of algorithms called the student exchange under partial fairness (SEPF). Each member of this class gives a partially stable matching that is not Pareto dominated by another partially stable matching (i.e., constrained efficient in the class of partially stable matchings). Moreover, any constrained efficient matching that Pareto improves upon a partially stable matching can be obtained via an algorithm within the SEPF class. We characterize the unique algorithm in the SEPF class that satisfies a desirable incentive property. The extension of the model to an environment with weak priorities enables us to provide a characterization result that proves the counterpart of the main result in Erdil and Ergin (2008).}, number={4}, journal={THEORETICAL ECONOMICS}, author={Dur, Umut and Gitmez, A. Arda and Yilmaz, Ozgur}, year={2019}, month={Nov}, pages={1309–1346} } @article{dur_wiseman_2019, title={School choice with neighbors}, volume={83}, ISSN={["1873-1538"]}, DOI={10.1016/j.jmateco.2018.12.001}, abstractNote={We consider the school choice problem where students who live near each other may prefer to be assigned to the same school. Even this very mild form of externality means that stable matchings may not exist, and that the student-proposing deferred acceptance mechanism may yield undesirable results — it is neither stable nor strategy-proof. We modify the school-proposing deferred acceptance mechanism to improve its performance. Our setting has important differences from both matching with couples and matching with preferences over colleagues.}, journal={JOURNAL OF MATHEMATICAL ECONOMICS}, author={Dur, Umut Mert and Wiseman, Thomas}, year={2019}, month={Aug}, pages={101–109} } @article{dur_kesten_2019, title={Sequential versus simultaneous assignment systems and two applications}, volume={68}, ISSN={["1432-0479"]}, DOI={10.1007/s00199-018-1133-9}, number={2}, journal={ECONOMIC THEORY}, author={Dur, Umut and Kesten, Onur}, year={2019}, month={Sep}, pages={251–283} } @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_2019, title={The modified Boston mechanism}, volume={101}, ISSN={["1879-3118"]}, DOI={10.1016/j.mathsocsci.2018.08.004}, abstractNote={Many school districts in the U.S. assign students to schools via the Boston mechanism. The Boston mechanism is not strategy-proof, and it is easy to manipulate. We slightly modify the Boston mechanism and show that the modified version outperforms the Boston mechanism in terms of strategy-proofness. In particular, the Boston mechanism is manipulable whenever the modified version is, but the modified version is not necessarily manipulable whenever the Boston mechanism is. We define a weaker form of consistency and characterize the modified Boston mechanism by this weaker form and a new axiom called respect of priority of the top-ranking students.}, journal={MATHEMATICAL SOCIAL SCIENCES}, author={Dur, Umut Mert}, year={2019}, month={Sep}, pages={31–40} } @article{dur_unver_2019, title={Two-Sided Matching via Balanced Exchange}, volume={127}, ISSN={["1537-534X"]}, DOI={10.1086/701358}, abstractNote={We introduce a new matching model to mimic two-sided exchange programs such as tuition and worker exchanges, in which export-import balances are required for longevity of programs. These exchanges use decentralized markets, making it difficult to achieve this goal. We introduce the two-sided top trading cycles, the unique mechanism that is balanced-efficient, worker-strategy-proof, acceptable, individually rational, and respecting priority bylaws regarding worker eligibility. Moreover, it encourages exchange, because full participation induces a dominant-strategy equilibrium for firms. We extend it to dynamic settings permitting tolerable yearly imbalances and demonstrate that its regular and tolerable versions perform considerably better than models of current practice.}, number={3}, journal={JOURNAL OF POLITICAL ECONOMY}, author={Dur, Umut Mert and Unver, M. Utku}, year={2019}, month={Jun}, pages={1156–1177} } @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{dur_mennle_seuken_2018, title={First-Choice Maximal and First-Choice Stable School Choice Mechanisms}, DOI={10.1145/3219166.3219201}, abstractNote={We investigate the class of school choice mechanisms that are first-choice maximal (FCM) (i.e., they match a maximal number of students to their reported first choices) and first-choice stable (FCS) (i.e., no students form blocking pairs with their reported first choices). FCM is a ubiquitous desideratum in school choice, and we show that FCS is the only rank-based relaxation of stability that is compatible with FCM. The class of FCM and FCS mechanisms includes variants of the well-known Boston mechanism as well as certain Asymmetric Chinese Parallel mechanisms. Regarding incentives, we show that while no mechanism in this class is strategyproof, the Pareto efficient ones are least susceptible to manipulation. Regarding student welfare, we show that the Nash equilibrium outcomes of these mechanisms correspond precisely to the set of stable matchings. By contrast, when some students are sincere, we show that more students may be matched to their true first choices in equilibrium than under any stable matching. Finally, we show how our results can be used to obtain a new characterization of the Boston mechanism (i.e., the most widely used FCM and FCS mechanism). On a technical level, this paper provides new insights about an influential class of school choice mechanisms. For practical market design, our results yield a potential rationale for the popularity of FCM and FCS mechanisms in practice.}, journal={ACM EC'18: PROCEEDINGS OF THE 2018 ACM CONFERENCE ON ECONOMICS AND COMPUTATION}, author={Dur, Umut and Mennle, Timo and Seuken, Sven}, year={2018}, pages={251–268} } @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.}, 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_kominers_pathak_sonmez_2018, title={Reserve Design: Unintended Consequences and the Demise of Boston's Walk Zones}, volume={126}, ISSN={["1537-534X"]}, DOI={10.1086/699974}, abstractNote={We show that in the presence of admissions reserves, the effect of the precedence order (i.e., the order in which different types of seats are filled) is comparable to the effect of adjusting reserve sizes. Either lowering the precedence of reserve seats at a school or increasing the school’s reserve size weakly increases reserve-group assignment at that school. Using data from Boston Public Schools, we show that reserve and precedence adjustments have similar quantitative effects. Transparency about these issues—in particular, how precedence unintentionally undermined intended policy—led to the elimination of walk zone reserves in Boston’s public school match.}, number={6}, journal={JOURNAL OF POLITICAL ECONOMY}, author={Dur, Umut and Kominers, Scott Duke and Pathak, Parag A. and Sonmez, Tayfun}, year={2018}, month={Dec}, pages={2457–2479} } @article{afacan_dur_2017, title={Incompatibility between stability and consistency}, volume={150}, ISSN={["1873-7374"]}, DOI={10.1016/j.econlet.2016.11.022}, abstractNote={Stability is a main concern in the school choice problem. However, it does not come for free. The literature shows that stability is incompatible with Pareto efficiency. Nevertheless, it has been ranked over Pareto efficiency by many school districts, and thereof, they are using stable mechanisms. In this note, we reveal another important cost of stability: “consistency”, which is a robustness property that requires from a mechanism that whenever some students leave the problem along with their assignments, the remaining students’ assignments do not change after running the mechanism in the smaller problem. Consequently, we show that no stable mechanism is consistent.}, journal={ECONOMICS LETTERS}, author={Afacan, Mustafa Oguz and Dur, Umut Mert}, year={2017}, month={Jan}, pages={135–137} } @article{afacan_dur_2017, title={When preference misreporting is Harm[less]ful?}, volume={72}, ISSN={["0304-4068"]}, DOI={10.1016/j.jmateco.2017.04.005}, abstractNote={In a school choice problem, we say that a mechanism is harmless if no student can ever misreport his preferences so that he is not hurt but someone else is. We consider two large classes of mechanisms, which include the Boston, the agent-proposing deferred acceptance, and the school-proposing deferred acceptance (sDA) mechanisms. Among all the rules in these two classes, the sDA is the unique harmless mechanism. We next provide two axiomatic characterizations of the sDA. First, the sDA is the unique stable, non-bossy, and “independent of an irrelevant student mechanism”. The last axiom requires that the outcome does not depend on the presence of a student who prefers being unassigned to any school. As harmlessness implies non-bossiness, the sDA is also the unique stable, harmless, and independent of an irrelevant student mechanism. To our knowledge, these axiomatizations as well as the well-known Gale and Shapley’s (1962), which reveals that the sDA is the student-pessimal stable mechanism, are the only characterizations of the sDA.}, journal={JOURNAL OF MATHEMATICAL ECONOMICS}, author={Afacan, Mustafa Oguz and Dur, Umut Mert}, year={2017}, month={Oct}, pages={16–24} } @article{dur_ikizler_2016, title={Many-to-one matchings without substitutability}, volume={144}, ISSN={0165-1765}, url={http://dx.doi.org/10.1016/J.ECONLET.2016.02.005}, DOI={10.1016/J.ECONLET.2016.02.005}, abstractNote={We study the existence of stable matchings in the many-to-one college admission problem when there are no restrictions on college preferences. We show that the existence of a stable allocation is strongly tied to students having “harmonious preferences” over their sets of acceptable college choices. In other words, without any assumption on college preferences, a stable matching exists for any college admission problem if and only if there is no subset of students with misaligned college rankings.}, journal={Economics Letters}, publisher={Elsevier BV}, author={Dur, Umut and Ikizler, Devrim}, year={2016}, month={Jul}, pages={123–126} }