Timing of preference submissions under the Boston mechanism

This paper considers a model of centralized college admission under the Boston mechanism where students may have uncertainty about their priorities. Students have homogeneous ordinal preferences over colleges, but their preference intensities vary, and the exam scores determine their priorities. In equilibrium, student application strategies take a cutoff form. The strategies depend on their exam scores under post-score submissions, on preference intensities under pre-exam submissions, and on both preference intensities and signals about their exam scores under pre-score submissions. Given these equilibrium strategies, students are better off under pre-exam and pre-score submissions than post-score submissions. When students with the same preference intensities and exam scores receive signals of different qualities, those with bad signals could be hurt by those with good signals.     

高考志愿填报机制与大学招生质量:一个基于择校机制理论的经验研究

本文关注高考志愿填报机制对优质大学学生质量的影响。我们首先论证由考前报改为考后报并引入平行志愿的改革模式可以带来事后的效率与公平("高分高就"),但未必增加事前的效率与公平("高能高就"或"高偏好高就")。基于某顶级学院的学生数据,利用各省历年志愿填报机制的变化,我们从实证上验证了这一假说:相对于考前无平行志愿的制度,该学院在考后填报制度下招收的学生高考成绩更高,但以大学学业衡量的学习能力或兴趣并没有更高。     

Preference submission timing in school choice matching: testing fairness and efficiency in the laboratory

We investigate the relative merits of the Boston and Serial Dictatorship mechanisms when the timing of students’ preference submission over schools varies within the structure of the mechanism. Despite the well-documented disadvantages of the Boston mechanism Abdulkadiroglu and Sonmez (American Economic Review 93:729–747 2003), we hypothesize that a Boston mechanism where students are required to submit their preferences before the realization of their exam scores, can in fact have fairness and efficiency advantages compared to the often favored Serial Dictatorship mechanism. We test these hypotheses in a series of laboratory experiments which vary by the class of mechanism implemented, and the preference submission timing by students, reflective of actual policy changes which have occurred in China. Our experimental findings confirm the efficiency hypothesis straightforwardly, and lend support to the fairness hypothesis when subjects have the chance to learn with experience. The results have important policy implications for school choice mechanism design when students’ relative rankings by schools are initially uncertain.     

Cardinal Bayesian allocation mechanisms without transfers

In allocating goods with no use of monetary transfers, random allocation mechanisms can be designed in order to elicit information on preference intensities. I study the nontransfer allocation of two ex-ante identical objects under Bayesian incentive compatibility, with symmetric agents and independent private valuations. I find the ex-ante utilitarian-optimal mechanism, in which the probability of receiving a specified object is used as “numeraire” to purchase probability units of the other object. I characterize this mechanism as an appropriate combination of lotteries, auctions and insurance. The latter element ensures that efficient auctions are feasible. If the problem is constrained to guarantee exactly one object per agent, then the optimal mechanism uses no information other than the agents? ordinal preferences.     

The roommates problem revisited

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.     

On the existence of a strictly strong Nash equilibrium under the student-optimal deferred acceptance algorithm

This study analyzes a preference revelation game in the student-optimal deferred acceptance algorithm in a college admission problem. We assume that each college's true preferences are known publicly, and analyze the strategic behavior of students. We demonstrate the existence of a strictly strong Nash equilibrium in the preference revelation game through a simple algorithm that finds it. Specifically, (i) the equilibrium outcome from our algorithm is the same matching as in the efficiency-adjusted deferred acceptance algorithm and (ii) in a one-to-one matching market, it coincides with the student-optimal von Neumann–Morgenstern (vNM) stable matching. We also show that (i) when a strict core allocation in a housing market derived from a college admission market exists, it can be supported by a strictly strong Nash equilibrium, and (ii) there exists a strictly strong Nash equilibrium under the college-optimal deferred acceptance algorithm if and only if the student-optimal stable matching is Pareto-efficient for students.     

On the nature of equilibria in a Downsian model with candidate valence

We analyze mechanisms that are used to allocate dormitory rooms to students at college campuses. Students consist of newcoming freshmen, who do not currently occupy any rooms, and more senior students each of whom occupies a room from the previous year. In addition to the rooms already occupied by the existing tenants, there are vacated rooms by the graduating class. Students have strict preferences over dormitory rooms. Each student shall be assigned a dormitory room in an environment where monetary transfers are not allowed. An existing tenant can move to another room as a result of the assignment. We show that you request my house–I get your turn mechanisms are the only mechanisms that are Pareto-efficient, individually rational, strategy-proof, weakly neutral, and consistent.     

Severe or gentle bankruptcy law: Which impact on investing and financing decisions?

This research investigates how legal sanctions prevailing under bankruptcy may impact on debt contracting and on investing decision. We model firms having the opportunity to engage (or not) faulty management. In case of default, the firms may escape costly bankruptcy by reaching a private agreement with the bank. We show that such renegotiation process may depend on the level of severity of bankruptcy law.Our approach helps in answering the following key questions: can bankruptcy costs always be internalized? Who benefits from accrued severity? Should the creditors accept a certain level of moral hazard from their debtors? Should bankruptcy law be extremely severe in order to ensure ex-ante efficiency? Does such severity depend on the financial environment?The model focuses on three equilibriums. The first equilibrium describes honest firms that choose the best investment project (ex-ante efficiency). Here, we show that bankruptcy costs can be avoided through private renegotiation (ex-post efficiency). Yet, the legislator cannot directly implement this equilibrium as it does not depend on the level of legal sanctions. A second equilibrium describes tricky firms turning to the less profitable and riskiest project. Here, default is still privately resolved: the occurrence of such equilibrium can be avoided owing to a minimal amount of legal sanctions that depend on the level of interest rate. Last, we consider firms that adopt mixed strategies regarding their investment policy. Here, two post-default bargains prevail (pooling or separating) and costly bankruptcy may occur.Simulations illustrate how the bank finally chooses between these equilibriums while the legal environment becomes more severe. For moderate levels of legal sanctions, banks may accept a certain level of faulty management, expecting to take advantage of bankruptcy punishment. An increase in sanctions, however, has a compelling effect on the companies towards honoring their commitments. Once the optimal equilibrium prevails, any additional increase in sanctions is ineffective as the players' strategies no longer depend on the legal environment. As a result, extreme severity is not required to ensure both ex-ante and ex-post efficiencies. Last, we find that a more severe bankruptcy law increases the protection of banks and may result in reduction of the contractual interest rate, which on the other hand benefits the debtors.     

Is assortative matching efficient?

Summary. This paper develops some general conditions under which complementarities between individual agents imply that assortative matching is efficient. Our analysis has four main findings. First, when agents are organized into equal-sized groups, just as in Becker (1973), the presence of within-group complementarities is sufficient for stratification to be efficient. Second, if group sizes vary, assortative matching may not be efficient even though complementarities are present, unless particular functional form assumptions are imposed. Third, the connection between assortative matching, complementarities and efficiency reemerges if one considers sequences of replications of the economy in which individual coalitions are uniformly bounded in size. Fourth, the presence of feedbacks from the composition of group memberships has important effects on efficient allocations and breaks any simple link between assortative matching and efficiency. Together, these results suggest that the characterization of the cross-section evolution of an efficiently sorted economy is likely to be highly complex. Received: September 25, 2001; revised version: February 26, 2002 RID="*" ID="*" We thank William Brock for many helpful conversations and Scott Page for detailed comments on an earlier draft of this paper. The National Science Foundation, John D. and Catherine T. MacArthur Foundation and Center for Urban Land Economic Research have generously provided financial support. Correspondence to: S. N. Durlauf     

Examining crop price effects on production decision and resource allocation: an ex-ante approach

This article examines the output price effects on the US crop production, employing an ex-ante approach to the differential systems of input demand and output supply. The estimation results of the differential input demand show that the expansion of crop production leads to an increase in acreage (i.e. extensive margin) and a proportional rise in input usage improving yield per acre (i.e. intensive margin). The substitutable relationship between fertilizer and land supports that crop producers have an option to choose either intensive or extensive margin in response to changes in their relative prices. In addition, the estimation results of the differential output supply highlight that the composition of crop supply can be altered by changes in ex-ante crop prices. The estimation results suggest that crop producers substitute corn supply for the supply of cotton, wheat and soybeans or vice versa. Based on the estimated elasticities, the decompositions of profit-maximizing input demand are conducted, which reveals that a change in ex-ante crop prices is associated closely with resource reallocation.     

“Timing Is Everything” and Marital Bliss

We first show that in a marriage market, when the stability of a matching is disturbed when a new agent joins the game, natural greedy behavior defines an equilibration procedure that converges to a stable matching for the extended problem. We then consider the iterative procedure under which agents join the game sequentially, and the natural greedy procedure is applied after the entrance of each agent. It is shown that this procedure converges to a stable matching for the original (global) problem and that for each agent, if the order of all other agents is given, he/she weakly improves his/her final outcome by deferring his/her arrival time. The agent that arrives last gets his/her optimal outcome under stable matchings. Journal of Economic Literature Classification Numbers: C78, C62.     

THE ESTIMATED EFFECT OF CATHOLIC SCHOOLING ON EDUCATIONAL OUTCOMES USING PROPENSITY SCORE MATCHING

This paper examines the effect of attending a Catholic high school on educational outcomes. The statistical analysis is based on data obtained from the US National Educational Longitudinal Study. Using propensity score matching methods to control for selection bias, we find that Catholic schooling improves maths test scores, with stronger effects for males than for females, but appears to have little effect (if any) on reading scores. Catholic schooling also raises high school graduation rates and substantially increases the likelihood of enrolment in a 4‐year college. Use of the difference‐in‐difference method suggests that the effect of Catholic schooling on changes in maths scores is more muted, though still statistically significant.     

The effect of vaccination on children's physical and cognitive development in the Philippines

We use data from the Cebu Longitudinal Health and Nutrition Survey (CLHNS) in the Philippines to link vaccination in the first 2 years of life with later physical and cognitive development in children. We use propensity score matching to estimate the causal effect of vaccination on child development. We find no effect of vaccination on later height or weight, but full childhood vaccination for measles, polio, Tuberculosis (TB), Diphtheria, Pertussis and Tetanus (DPT) significantly increases cognitive test scores relative to matched children who received no vaccinations. The size of the effect is large, raising test scores, on average, by about half an SD.     

Procedurally fair and stable matching

Summary. We motivate procedural fairness for matching mechanisms and study two procedurally fair and stable mechanisms: employment by lotto (Aldershof et al. , 1999) and the random order mechanism (Roth and Vande Vate, 1990, Ma, 1996). For both mechanisms we give various examples of probability distributions on the set of stable matchings and discuss properties that differentiate employment by lotto and the random order mechanism. Finally, we consider an adjustment of the random order mechanism, the equitable random order mechanism, that combines aspects of procedural and endstate fairness.Received: 9 September 2003, Revised: 12 December 2004, JEL Classification Numbers: C78, D63. Correspondence to: Flip KlijnWe thank two referees and a co-editor for helpful comments and suggestions. B. Klauss and F. Klijns research has been supported by Ramón y Cajal contracts of the Spanish Ministerio de Ciencia y Tecnología. The work of the authors has also been partially supported by Research Grant BEC2002-02130 from the Spanish Ministerio de Ciencia y Tecnología and by the Barcelona Economics Program of CREA. This paper is part of the Polarization and Conflict Project CIT-2-CT-2004-506084 funded by the European Commission-DG Research Sixth Framework Programme. This article reflects only the authors views and the Community is not liable for any use that may be made of the information contained therein.     

Accountability,incentives and behavior: the impact of high-stakes testing in the Chicago Public Schools

The recent federal education bill, No Child Left Behind, requires states to test students in grades 3 to 8 each year and to judge school performance on the basis of these test scores. While intended to maximize student learning, there is little empirical evidence about the effectiveness of such policies. This study examines the impact of an accountability policy implemented in the Chicago Public Schools in 1996–1997. Using a panel of student-level, administrative data, I find that math and reading achievement increased sharply following the introduction of the accountability policy, in comparison to both prior achievement trends in the district and to changes experienced by other large, urban districts in the mid-west. However, for younger students, the policy did not increase performance on a state-administered, low-stakes exam. An item-level analysis suggests that the observed achievement gains were driven by increases in test-specific skills and student effort. I also find that teachers responded strategically to the incentives along a variety of dimensions—by increasing special education placements, preemptively retaining students and substituting away from low-stakes subjects like science and social studies.     

Bias-corrected estimates of reduction of post-surgery length of stay and corresponding cost savings through the widespread national implementation of fast-tracking after liver transplantation: a quasi-experimental study

Background: Fast-tracking is an approach adopted by Mayo Clinic in Florida’s (MCF) liver transplant (LT) program, which consists of early tracheal extubation and transfer of patients to surgical ward, eliminating a stay in the intensive care unit in select patients. Since adopting this approach in 2002, MCF has successfully fast-tracked 54.3% of patients undergoing LT.

Objectives: This study evaluated the reduction in post-operative length of stay (LOS) that resulted from the fast-tracking protocol and assessed the potential cost saving in the case of nationwide implementation.

Methods: A propensity score for fast-tracking was generated based on MCF liver transplant databases during 2011–2013. Various propensity score matching algorithms were used to form control groups from the United Network of Organ Sharing Standard Analysis and Research (STAR) file that had comparable demographic characteristics and health status to the treatment group identified in MCF. Multiple regression and matching estimators were employed for evaluation of the post-surgery LOS. The algorithm generated from the analysis was also applied to the STAR data to determine the proportion of patients in the US who could potentially be candidates for fast-tracking, and the potential savings.

Results: The effect of the fast-tracking on the post-transplant LOS was estimated at approximately from 2.5 (p-value?=?0.001) to 3.2 (p-value?Conclusion: The fast-track program was found to be effective in reducing post-transplant LOS, although the reduction appeared to be less than previously reported. Nationwide implementation of fast-tracking could result in substantial cost savings without compromising the patient outcome.     

Identity,homophily and in-group bias

Many instances of social interaction display either or both of the following well-documented phenomena. People tend to interact with similar others (homophily). They also tend to treat others of shared social identity more favorably (in-group bias). While both phenomena involve some degree of discrimination towards others, a systematic study of their relations and interplay is yet missing. In this paper we report the findings of an experiment designed to address this issue. Participants are exogenously and randomly assigned to one of two groups. Subsequently they play a sequence of eight games with either an in-group or an out-group member. In treatment EXO in- and out-group matches are formed exogenously, while in ENDO participants can choose between in- and out-group matches. We find strong evidence of in-group bias in EXO, and strong evidence of homophily in ENDO. In-group biases, however, either decrease or disappear altogether under endogenous matching. We show that self-selection of homophilous agents into in-group matches cannot explain this fact. We also find that homophily is strongly correlated with risk aversion, and we build on this evidence to derive a rationale for both the existence of homophily and the disappearance of in-group biases under endogenous matching.     

Choosing propensity score matching over regression adjustment for causal inference: when,why and how it makes sense

Summary

This study identified when regression adjustment fails to adjust adequately for differences in observed covariates and where propensity score matching is the only alternative.

Multivariate analysis might fail to adjust for observed confounders if:

• 1. The means of the propensity scores in the two groups are more than one-half a standard deviation apart unless distributions of the covariates in both groups are nearly symmetric, sample sizes of the two groups are approximately the same and distributions of the covariates in the two groups have similar variances;

• 2. The ratio of the propensity score variances in the two groups is significantly different from one;

• 3. The ratio of residual variances in the two groups after adjusting for the propensity score is significantly different from one.

Conducted retrospective analysis showed that the treatment effect would be an estimated $305 (or 26%) less if the misspecified outcome model had been chosen.     

A Solomonic solution to the problem of assigning a private indivisible good

A benevolent Planner wishes to assign an indivisible private good to n claimants, each valuing the object differently. Individuals have quasi-linear preferences. Therefore, the possibility of transfers is allowed. A second-best efficient mechanism is a strategy-proof and anonymous mechanism that is not Pareto dominated by another strategy-proof and anonymous mechanism. In this context, we identify three conditions that are necessary and, together with Voluntary Participation, sufficient for a mechanism to be second-best efficient. This set includes mechanisms that destroy the good at certain profiles. For domains comprising two individuals we provide an explicit characterization of the family of second-best efficient mechanisms.     

Preemption in a real option game with a first mover advantage and player-specific uncertainty

In this paper a two-player real option game with a first-mover advantage is analyzed, where payoffs are driven by a player-specific stochastic state variable. It is shown that there exists an equilibrium which has qualitatively different properties from those in standard real option games driven by common stochastic shocks. The properties of the equilibrium are four-fold: (i) preemption does not necessarily occur, (ii) if preemption takes place, the rent-equalization property holds, (iii) for almost all sample paths it is clear ex-ante which player invests first, and (iv) it is possible that both players invest simultaneously, even if that is not optimal. It is argued from simulations that real option games with a common one-dimensional shock do not provide a good approximation for games with player-specific uncertainty, even if these are highly correlated.