Unpaired Kidney Exchange: Overcoming Double Coincidence of Wants without Money

74 Pages Posted: 10 Sep 2020

See all articles by Mohammad Akbarpour

Mohammad Akbarpour

Stanford University

Julien Combe

CREST - Ecole polytechnique

Yinghua He

University of Toulouse 1 - Toulouse School of Economics (TSE)

Victor Hiller

affiliation not provided to SSRN

Robert Shimer

University of Chicago - Department of Economics; National Bureau of Economic Research (NBER)

Olivier Tercieux

Paris-Jourdan Sciences Economiques (PSE)

Multiple version iconThere are 2 versions of this paper

Date Written: September 7, 2020

Abstract

For an incompatible patient-donor pair, kidney exchanges often forbid receipt-before-donation (the patient receives a kidney before the donor donates) and donation-before-receipt, causing a double-coincidence-of-wants problem. Our proposal, the Unpaired kidney exchange algorithm, uses “memory” as a medium of exchange to eliminate these timing constraints. In a dynamic matching model, we prove that Unpaired delivers a waiting time of patients close to optimal and substantially shorter than currently utilized state-of-the-art algorithms. Using a rich administrative dataset from France, we show that Unpaired achieves a match rate of 57 percent and an average waiting time of 440 days. The (infeasible) optimal algorithm is only slightly better (58 percent and 425 days); state-of-the-art algorithms deliver less than 34 percent and more than 695 days. We draw similar conclusions from the simulations of two large U.S. platforms. Lastly, we propose a range of solutions that can address the potential practical concerns of Unpaired.

Keywords: Kidney exchange, medium of exchange, dynamic matching

JEL Classification: D47, C78, E00

Suggested Citation

Akbarpour, Mohammad and Combe, Julien and He, Yinghua and Hiller, Victor and Shimer, Robert J. and Tercieux, Olivier, Unpaired Kidney Exchange: Overcoming Double Coincidence of Wants without Money (September 7, 2020). University of Chicago, Becker Friedman Institute for Economics Working Paper No. 2020-126, Available at SSRN: https://ssrn.com/abstract=3689708 or http://dx.doi.org/10.2139/ssrn.3689708

Mohammad Akbarpour

Stanford University ( email )

Julien Combe

CREST - Ecole polytechnique ( email )

Office 4082, CREST - Ecole polytechnique
5 Avenue Le Chatelier
Palaiseau, 91120
France

HOME PAGE: http://https://sites.google.com/site/combeju

Yinghua He

University of Toulouse 1 - Toulouse School of Economics (TSE) ( email )

21 allée de Brienne
Toulouse, 31015
France

Victor Hiller

affiliation not provided to SSRN

No Address Available

Robert J. Shimer (Contact Author)

University of Chicago - Department of Economics ( email )

1126 East 59th Street
Chicago, IL 60637
United States
773-702-9015 (Phone)
773-702-8490 (Fax)

HOME PAGE: http://home.uchicago.edu/~shimer/

National Bureau of Economic Research (NBER)

1050 Massachusetts Avenue
Cambridge, MA 02138
United States

Olivier Tercieux

Paris-Jourdan Sciences Economiques (PSE) ( email )

48, BD Jourdan
75014 Paris
France

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