Work in Progress

Beyond Truth-telling: A Replication Study on School Choice

In a recent paper, Fack et al. (2019, American Economic Review) convincingly argue and theoretically demonstrate that there may be strong incentives for students to play non-truth-telling strategies when reporting preferences over schools, even when the celebrated deferred acceptance algorithm is employed. Their statistical test also rejects the (weak) truth-telling assumption in favour of another assumption, called stability, using a single data set on school choice in Paris. This paper uses Swedish school choice data and replicates their empirical finding in 52 of the 58 investigated data sets (P-value threshold 0.05).

Co-authors: Dany Kessel, Nils Lager, Elisabet Olme and Simon Reese

Download the working paper here

Status: Work in progress



Status Quo Bias and Hidden Condorcet Cycles in Binary Referendums

In most real-life binary referendums, there are several alternatives that potentially can challenge the status quo alternative. Depending on which alternative that is selected, the voters are also differently likely to caste their vote on it. The fact that there are several potential challenger alternatives also means that there may exist Condorcet cycles that only can be identified by taking into account the alternatives that not are listed on the ballot. We analyse such ``hidden'' cycles in a simple theoretical framework where Condorcet cycles cannot exist, but may emerge when taking into account that voters often experience a reluctance to abandon the status quo alternative. Necessary and sufficient conditions for the existence of hidden Condorcet cycles are derived and a Monte Carlo simulation finds (in different scenarios) that the probability is roughly one percent.

Download by klicking here (version from November 21, 2022)

Status: Revise & Resubmit (2nd round)



Sequential School Choice with Public and Private Schools

Motivated by school admission systems used in, e.g., Turkey and Sweden, this paper investigates a sequential two-stage admission system with public and private schools. To perform the analysis, relevant axioms and equilibrium notions need to be tailored for the considered dynamic setting. In particular, a notion of truthfulness, referred to as straightforwardness, is introduced. In sharp contrast to classic one-stage admission systems, sequentiality leads to a trade-off between the existence of a straightforward (i.e., truthful) equilibrium and nonwastefulness. Given this insight, we identify the unique set of rules for two-stage admission systems that guarantees the existence of a straightforward equilibrium and, at the same time, reduces the number of wasted school seats. Several existing admission systems are also theoretically analyzed within our general framework and empirically evaluated using school choice data from Sweden. The latter analysis allows us to quantify various trade-offs in sequential admission systems.

Coauthors: Umut Dur, Sinan Ertemel and Onur Kesten

Download by klicking here (version from October 31, 2023). 

Status: Revise & resubmit (2nd round)



Dynamic Refugee Matching

Asylum seekers are often assigned to a locality in their host country directly upon arrival based on some type of uninformed dynamic matching system which does not take the background of the asylum seekers into consideration. This paper proposes an informed, intuitive, easy-to-implement and computationally efficient dynamic mechanism for matching asylum seekers to localities. This mechanism can be adopted in any dynamic refugee matching problem given locality-specific quotas and that asylum seekers can be classified into specific types. We demonstrate that any matching selected by the proposed mechanism is Pareto efficient and that envy between localities is bounded by a single asylum seeker. Via simulation, we evaluate the performance of the proposed mechanism in settings that resemble the US and the Swedish situations, and show that our mechanism outperforms uninformed mechanisms even in presence of severe misclassification error in the estimation of asylum seeker types.

Coauthors: Lars Ehlers and Alessandro Martinello

Download by klicking here (version from October 29, 2018). 

Status: Reject & resubmit (first round)



Non-Manipulable House Exchange under (Minimum) Equilibrium Prices

We consider a market with indivisible objects, called houses, and money. On this market, each house is initially owned (or rented) by some agent and each agent demands precisely one house. The problem is to identify the complete set of direct allocation mechanisms that can be used to reallocate the houses among the agents. The focus is on price mechanisms, i.e., mappings of preference profiles to price equilibria, that are strategy-proof and satisfy an individual rationality condition. We prove that the only mechanism that satisfies these conditions is a price mechanism with a minimal equilibrium price vector. The result is not true in full preference domain. Instead, we identify a smaller domain, that contains almost all profiles, where the result holds.

Coauthors: Lars-Gunnar Svensson and Lars Ehlers

Download by klicking here (version from December 15, 2020). 

Status: Reject & resubmit (first round)



Multiple Pricing for Personal Assistance Services

This paper provides a general theoretical framework that captures the essential features of a Swedish reform where private and public health care providers serve patients with certain functional impairments. Because providers receive a fixed hourly compensation for their services (identical across patient types) and only private providers can reject service requests from patients, private providers avoid the costliest patients, resulting in a monetary deficit for public providers. To partially overcome this problem, a multiple pricing (reimbursement) scheme is proposed and its solution is characterized. The results suggest that there are some fundamental trade-offs, e.g., between the goals of containing costs and restricting choices for patients, but that the suggested pricing scheme may substantially reduce the deficits for public providers without affecting the total budget set by the central government.

Coauthors: Lina Maria Ellegård, Andreea Enache, Albin Erlanson, and Prakriti Thami. 

Download by klicking here (version from October 25, 2023). 

Status: Reject & resubmit (first round)


Work in progress (papers available soon):