Contests at the workplace with and without prize selection: testing theory in a field experiment

We conduct a field experiment with 302 workers of the microcredit company in Russia to study the effects of the different designs of a contest for monetary prizes at the workplace. We consider a standard all-pay auction design with two and four prizes of different size and compare it to "parallel" contests with the same prizes, but where participants have to choose the prize prior to the start of the competition and then the winner is selected only among the players who chose the same prize. Despite the theoretical predictions, the parallel contests lead to higher efforts for all players, but mainly by lower-ability players. Division of prizes leads to the predicted effects. In parallel contests, too many players choose the higher prize than equilibrium suggests. Overall, the parallel version of contests appeared to be more profitable for the firm

Improving Transparency and Verifiability in School Admissions: Theory and Experiment

Students participating in centralized admissions procedures do not typically have access to the information used to determine their matched school, such as other students' preferences or school priorities. This can lead to doubts about whether their matched schools were computed correctly (the 'Verifiability Problem') or, at a deeper level, whether the promised admissions procedure was even used (the 'Transparency Problem'). In a general centralized admissions model that spans many popular applications, we show how these problems can be addressed by providing appropriate feedback to students, even without disclosing sensitive private information like other students' preferences or school priorities. In particular, we show that the Verifiability Problem can be solved by (1) publicly communicating the minimum scores required to be matched to a school ('cutoffs'); or (2) using 'predictable' preference elicitation procedures that convey rich 'experiential' information. In our main result, we show that the Transparency Problem can be solved by using cutoffs and predictable procedures together. We find strong support for these solutions in a laboratory experiment, and show how they can be simply implemented for popular school admissions applications involving top trading cycles, and deferred and immediate acceptance

The iterative deferred acceptance mechanism

Lately, there has been an increase in the use of sequential mechanisms, instead of the traditional direct counterparts, in college admissions in many countries, including Germany, Brazil, and China. We describe these mechanisms and identify their shortcomings in terms of incentives and outcome properties. We introduce a new mechanism, which improves upon these shortcomings. Unlike direct mechanisms, which ask students for a full preference ranking over colleges, our mechanism asks students to sequentially make choices or submit partial rankings from sets of colleges. These are used to produce a tentative allocation at each step. If at some point it is determined that a student can no longer be accepted into previous choice, then she is asked to make another choice among colleges that would tentatively accept her. Participants following the simple strategy of choosing the most-preferred college in each step is an ex-post equilibrium that yields the Student-Optimal Stable Matching

Iterative versus standard deferred acceptance: experimental evidence

We run laboratory experiments where subjects are matched to colleges, and colleges are not strategic agents. We test the Gale-Shapley Deferred Acceptance (DA) mechanism versus the Iterative Deferred Acceptance Mechanism (IDAM), a matching mechanism based on a new family of procedures being used in the field, in which information about tentative allocations is provided while students make choices. We consider two variations of IDAM: one in which they are only informed about whether they are tentatively accepted or not (IDAM-NC) and one in which students are additionally informed at each step of the tentative cutoff values for acceptance at each school (IDAM). A significantly higher proportion of stable outcomes is reached both under IDAM and IDAM-NC than under DA. The difference can be explained by a higher proportion of subjects following an equilibrium strategy akin to truthful behavior under IDAM and IDAM-NC than truthful behavior itself under DA. Moreover, the provision of intermediate cutoff values in IDAM leads to higher rates of equilibrium behavior than in IDAM-NC and a higher robustness of stability between the rounds of experiments. Our findings provide substantial support for the rising practice of using iterative mechanisms in centralized college admissions in practice

Monkey see, monkey do: truth-telling in matching algorithms and the manipulation of others

We test the effect of the amount of information on the strategies played by others in the theoretically strategy-proof Top Trading Cycles (TTC) mechanism. We find that providing limited information on the strategies played by others has a negative and significant effect in truth-telling rates. Subjects report truthfully more often when either full information or no information on the strategies played by others is available. Our results have potentially important implications for the design of markets based on strategy-proof matching algorithms

Pick-an-object Mechanisms

We introduce a new family of mechanisms for one-sided matching markets, denoted pick-an-object (PAO) mechanisms. When implementing an allocation rule via PAO, agents are asked to pick an object from individualized menus. These choices may be rejected later on, and these agents are presented with new menus. When the procedure ends, agents are assigned the last object they picked. We characterize the allocation rules that can be sequentialized by PAO mechanisms, as well as the ones that can be implemented in a robust truthful equilibrium. We justify the use of PAO as opposed to direct mechanisms by showing that its equilibrium behavior is closely related to the one in obviously strategy-proof (OSP) mechanisms, but includes commonly used rules, such as Gale-Shapley DA and Top Trading Cycles, which are not OSP-implementable. We run laboratory experiments comparing truthful behavior when using PAO, OSP, and direct mechanisms to implement different rules. These indicate that individuals are more likely to behave in line with the theoretical prediction under PAO and OSP implementations than their direct counterparts

Charitable Giving by the Poor: A Field Experiment in Kyrgyzstan

In a large-scale natural field experiment, we partnered with a microlending company in Kyrgyzstan that asked over 180,000 of its clients for donations to social projects as a form of corporate philanthropy. In a 2 × 2 design, we explored two main (preregistered) hypotheses about giving by the poor. First, based on a conjecture that the poor are more price sensitive than the rich and in contrast to previous studies, we hypothesize that matching incentives induce crowding in of out-of-pocket donations. Second, we hypothesize that our population cares about their proximity to the charitable project. We find evidence in favor of the former hypothesis but not the latter. Previous studies of charitable giving focus on middle- or high-income earners in Western countries, neglecting the poor, although the lowest-income groups are often shown to contribute substantial shares of their income to charitable causes. Our results challenge the evidence in the extant literature but are in line with our theoretical model. The implications for fundraising managers are that the optimal design of fundraising campaigns crucially depends on the targeted groups and that donation matching is successful in stimulating participation in poorer populations

Confidence and College Applications: Evidence from a Randomized Intervention

This paper investigates the role self-confidence plays in college applications. Using incentivized experiments, we measure the self-confidence of more than 2,000 students applying to colleges in France. This data reveals that the best female and low-SES students significantly underestimate their rank in the grade distribution compared to male and high-SES students. By matching our survey data with administrative data on real college applications and admissions, we show that miscalibrated confidence affects college choice on top of grades. We then estimate the impact of a randomized intervention that corrects students' under- and overconfidence by informing them of their real rank in the grade distribution. The treatment reduces the impact of under- and overconfidence for college applications, to the point where only grades but not miscalibrated confidence predict the application behavior of treated students. Providing feedback also makes the best students, who were initially underconfident, apply to more ambitious programs with stronger effects for female and low-SES students

The iterative deferred acceptance mechanism

We introduce a new mechanism for matching students to schools or universities, denoted Iterative Deferred Acceptance Mechanism (IDAM), inspired by procedures currently being used to match millions of students to public universities in Brazil and China. Unlike most options available in the literature, IDAM is not a direct mechanism. Instead of requesting from each student a full preference over all colleges, the student is instead repeatedly asked to choose one college among those which would accept her given the current set of students choosing that college. Although the induced sequential game has no dominant strategy, when students simply choose the most preferred college in each period (denoted the straightforward strategy), the matching that is produced is the Student Optimal Stable Matching. Moreover, under imperfect information, students following the straightforward strategy is an Ordinal Perfect Bayesian Equilibrium. Based on data from 2016, we also provide evidence that, due to shortcomings which are absent in the modified version that we propose, the currently used mechanism in Brazil fails to assist the students with reliable information about the universities that they are able to attend, and are subject to manipulation via cutoffs, a new type of strategic behavior that is introduced by this family of iterative mechanisms and observed in the field