Friday, January 28, 2022

Kidnapping and ransom in Nigeria

 Paying ransom is a repugnant transaction that looks different ex ante and ex post.  In Nigeria, where kidnapping is rampant, the government's view is increasingly that ransom payments should be prohibited, to make kidnapping unprofitable.  But after family members have been kidnapped, families are reluctant to let them be murdered, and are consequently eager to negotiate a ransom.

The WSJ has the story

A Kidnapping Negotiator Gets His Biggest Test: Saving His Own Wife. Abdullahi Tumburkai volunteers to help bargain with kidnappers in what has become a crisis of abductions in Nigeria.  By Joe Parkinson 

"Mr. Tumburkai estimates he has helped free more than 80 people across Nigeria’s northwest over the past year, in what has become one of the world’s worst kidnapping crises. Kidnapping for ransom has become a brutally profitable business across the country by heavily armed criminal gangs exploiting the government’s weak security presence. Gangs abducted an estimated tens of thousands of Nigerians in 2021, including more than 1,200 children seized from their schools.
"If they don’t haggle a ransom the victims can afford, hostages could be killed. If they succeed, these brokers make themselves a target among those who oppose any negotiations with kidnappers. The work embodies a moral argument that divides governments across the world: Should you pay to secure the return of hostages?

"Nigeria’s government and many community leaders say freelancers like Mr. Tumburkai are making the problem worse by creating a pathway for payments that finance terrorism and encouraging more kidnappings.

"Garba Shehu, Nigeria’s presidential spokesman, said that negotiating with kidnappers was “totally unacceptable” and that the government frowns at ransom payments. “It’s the responsibility of the police to advise persons whose relatives were kidnapped on what to do,” he said.
"On Wednesday, Nigeria’s attorney general said the groups responsible for the kidnappings would be formally listed as terrorists, and as a result anyone negotiating with kidnappers could be charged with financing terror groups."

Thursday, January 27, 2022

A brief history of deceased organ donation in one career--Howard Nathan retires

Organ donation and transplantation is still new enough that significant parts of its history can have been experienced in one career.  The WSJ reports on Howard Nathan's retirement from the Gift of Life Organ Procurement Organization, which he joined in 1978:

Howard Nathan Spent Decades ‘On Call’ for Organ Transplants. The CEO of the Gift of Life Donor Program is stepping down after a long career connecting organ donors with patients in need.  By Emily Bobrow

"When Mr. Nathan, 68, first joined the nonprofit that would become Gift of Life, he was one of three employees. Working around the clock, he traveled to hospitals in Pennsylvania, Delaware and New Jersey for hard conversations with grieving families and then made calls to surgeons in the hope of matching a donated organ with a waiting patient. “We would be driving on the Turnpike with a kidney in the car at three in the morning,” Mr. Nathan recalls on a video call from Gift of Life headquarters in central Philadelphia. “In the early days we had to make it up as we went along.”

"In 1994 he helped to draft Pennsylvania’s landmark organ donation law, which mandated that hospitals call organ-procurement organizations whenever a patient died. “Hospitals used to call when they wanted to. We were like Maytag repairmen waiting by the phone,” Mr. Nathan remembers. The law, which included funds for public-awareness campaigns and gave people a chance to register as organ donors when getting or renewing a driver’s license, increased donations by 43% in three years, he says. It became the model for a federal law in 1998.


"Brain death was a fairly new concept when Mr. Nathan first worked as an organ-donation coordinator—a job held by maybe 200 people around the country at the time. “We really had to teach and train people in the medical and legal aspects of donation,” he says.


"When Mr. Nathan entered the field, the success rate for transplants hovered at 30-35%. With the discovery in the early 1980s of immunosuppressant drugs, which curb the body’s natural rejection of foreign body parts, success rates have climbed above 90%."

HT: Frank McCormick

Wednesday, January 26, 2022

Matching and market design in the January issue of Theoretical Economics

 The current issue has three papers on the market design of matching markets.

Theoretical Economics, Volume 17, Number 1 (January 2022): Table of Contents

Here are the market design articles that caught my eye:

Rank-optimal assignments in uniform markets  by Afshin Nikzad

"We prove that in a market where agents rank objects independently and uniformly at random, there exists an assignment of objects to agents with a constant average rank (i.e., an average rank independent of the market size). The proof builds on techniques from random graph theory and the FKG inequality (Fortuin et al. (1971)). When the agents’ rankings are their private information, no Dominant Strategy Incentive Compatible mechanism can implement the assignment with the smallest average rank; however, we show that there exists a Bayesian Incentive Compatible mechanism that does so. Together with the fact that the average rank under the Random Serial Dictatorship (RSD) mechanism grows infinitely large with the market size, our findings indicate that the average rank under RSD can take a heavy toll compared to the first-best, and highlight the possibility of using other assignment methods in scenarios where average rank is a relevant objective.


Family ties: school assignment with siblings by Umut Dur, Thayer Morrill, and William Phan

"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."


Optimal organ allocation policy under blood-type barriers with the donor-priority rule by Jaehong Kim and Mengling Li

"Shortages in organs for transplantation have resulted in a renewed interest in designing incentive policies to promote organ supply. The donor-priority rule, which grants priority for transplantation based on deceased organ donor registration status, has proven to be effective in both theory and practice. This study investigates the implications of the donor-priority rule for optimal deceased organ allocation policy design under a general formulation of blood-type barriers. We find that for any blood typing and organ matching technology, reserving type X organs for only type X patients maximizes the aggregate donation rate under regular distributions, which also ensures equity in organ sharing. Moreover, this is the unique optimal allocation policy if and only if the directed compatibility graph that corresponds to a given organ matching technology is acyclic."

Tuesday, January 25, 2022

Multiple offer mechanisms in school choice, when information gathering is costly

 When it's costly to gather information needed to inform yourself about your own preferences, having a guaranteed offer in hand may justify the effort to gather necessary information.  Here's a paper that considers that as a first order issue:

The Case for Dynamic Multi-offer Mechanisms, by Julien Grenet YingHua He Dorothea Kübler

January 2022, (Forthcoming: The Journal of Political Economy)

Abstract: We document quasi-experimental evidence against the common assumption in the matching literature that agents have full information on their own preferences. In Germany’s university admissions, the first stages of the Gale-Shapley algorithm are implemented in real time, allowing for multiple offers per student. We demonstrate that non-exploding early offers are accepted more often than later offers, despite not being more desirable. These results, together with survey evidence and a theoretical model, are consistent with students’ costly discovery of preferences. A novel dynamic multi-offer mechanism that batches early offers improves matching efficiency by informing students of offer availability before preference discovery.

Monday, January 24, 2022

23rd ACM Conference on Economics and Computation (EC’22)--call for papers (by Feb 10)

 The deadline is 11:59pm EDT on Feb 10, but I'm guessing that papers have a good chance of being received as late as midnight.

23rd ACM Conference on Economics and Computation (EC’22): Call for Contributions

"TL;DR for Seasoned Authors:

Papers submitted to EC’22 must select one of four methodological tracks and up to two content areas. The list of tracks and content areas can be found below.

EC’22 is continuing the forward-to-journal option as in previous years.

EC’22 is currently planned as a primarily in-person event, with some components (e.g., poster sessions and tutorials) to be held either virtually or in a hybrid format. Presenters of accepted papers who cannot (or do not feel comfortable to) travel to EC’22 will have the option to present their paper virtually.


Timetable for Authors

February 10, 2022 (11:59 pm EST): Paper submission deadline

April 11, 2022 (11:59pm EDT): Reviews sent to authors for feedback

April 14, 2022 (11:59pm EDT): Author responses due

May 8, 2022: Paper accept/reject notifications

May 18, 2022 (11:59pm EDT): Camera-ready versions of accepted papers due

July 11-15, 2022: Conference technical program"


Program Chairs:

Sven Seuken (University of Zurich and ETH AI Center)

Ilya Segal (Stanford University)

Contact the PC chairs at 

Track Chairs:

Theory: Robert Kleinberg (Cornell University) and Aaron Roth (University of Pennsylvania)

Applied Modeling: Gabriel Weintraub (Stanford University)

Empirics: Georgios Zervas (Boston University)

AI: Kevin Leyton-Brown (University of British Columbia)

EC’22 will use the following areas:

Mechanism design

Auctions and pricing

Market design and matching markets

Contract design

Online platforms and applications

Econometrics, ML, and data science

Equilibria, learning, and dynamics in games

Social choice and voting theory

Social networks and social learning

Fair division

Market equilibria

Crowdsourcing and information elicitation

Privacy, algorithmic fairness, social good, and ethics

Blockchain and cryptocurrencies

Behavioral economics and bounded rationality

Area Chairs: Nick Arnosti (University of Minnesota)  Haris Aziz (University of New South Wales)  Moshe Babaioff (Microsoft Research)  Yakov Babichenko (Technion)  Bruno Biais (Toulouse School of Economics)  Martin Bichler (Technical University of Munich)  Larry Blume (Cornell University)  Liad Blumrosen (Hebrew University)  Benjamin Brooks (University of Chicago) Yang Cai (Yale University)  Agostino Capponi (Columbia University)  Yeon-Koo Che (Columbia University)  Rachel Cummings (Columbia University)  Nikhil Devanur (Amazon)  John Dickerson (University of Maryland)  Laura Doval (Columbia University)  Paul Duetting (Google Research)  Michal Feldman (Tel Aviv University)  Ashish Goel (Stanford University)  Hanna Halaburda (New York University Stern School of Business)  Hoda Heidari (Carnegie Mellon University)  Martin Hoefer (Goethe University Frankfurt)  Ian Kash (University of Illinois at Chicago)  Fuhito Kojima (University of Tokyo)  Nicolas Lambert (MIT)  Jacob Leshno (The University of Chicago Booth School of Business)  Shengwu Li (Harvard University)  Annie Liang (University of Pennsylvania)  Brendan Lucier (Microsoft Research)  Mohammad Mahdian (Google Research)  Azarakhsh Malekian (University of Toronto)  R. Preston McAfee  Reshef Meir (Technion)  Jamie Morgenstern (University of Washington)  Thayer Morril (North Carolina State University)  Denis Nekipelov (University of Virginia)  Sigal Oren (Ben-Gurion University)  Michael Ostrovsky (Stanford University)  Rafael Pass (Cornell University)  Ariel Procaccia (Harvard University)  Marek Pycia (University of Zurich)  Marzena Rostek (University of Wisconsin-Madison)  Jay Sethuraman (Columbia University)  Nisarg Shah (University of Toronto)  Peng Shi (University of Southern California)  Alex Slivkins (Microsoft Research)  Eric Sodomka  Nicolas Stier-Moses (Facebook)  Siddharth Suri (Microsoft Research)  Steve Tadelis (Berkeley–Haas)  Inbal Talgam-Cohen (Technion)  Alexander Teytelboym (University of Oxford)  Utku Unver (Boston College)  Vijay Vazirani (University of California, Irvine)  Jens Witkowski (Frankfurt School of Finance & Management)  James Wright (University of Alberta)  Lirong Xia (Rensselaer Polytechnic Institute)  Bumin Yenmez (Boston College)  Yair Zick (University of Massachusetts, Amherst)  Aviv Zohar (The Hebrew University of Jerusalem)

Sunday, January 23, 2022

Paired kidney donation performed in Germany--a guest post by Ágnes Cseh

 Below is a post written by Ágnes Cseh, about a kidney exchange conducted legally in Germany, in October, after being identified outside of the medical establishment. (The links she supplies are all worth looking into, and Google translate works well enough.)

"The legal basis for a living organ donation in Germany is a relationship or close personal connection between donor and recipient. This well-meant rule implicitly forbids paired kidney donation, because even though recipient and donor are closely related in each of the two pairs participating in a paired donation, the physical graft a patient receives technically comes from the relative of the other recipient.

A cumbersome, but legal way around the regulation is to establish a close personal connection between all four persons involved in a paired donation. Then, an ethical committee might approve of the two transplants separately. This constellation even inspired filmmakers to shoot a fictional movie about such a venture -- the genre is supposed to be comedy. In reality, paired transplants have been performed very sporadically in the past years in Germany.

A new initiative offers a centralized platform for paired kidney donations. It is run by Susanne Reitmaier, an activist fighting for the complete legalization of paired donations and Ágnes Cseh, a researcher specialized in matching theory. They maintain a database of the voluntarily submitted medical data of incompatible recipient-donor pairs. If a possible match among these pairs is found, then the two pairs are put into contact with each other so that they can establish the personal connection required by the law.

The first match in this program was identified in July 2020. After a long journey (see the detailed report in English here and in German here), the transplants were finally performed in October 2021 in Berlin. The ethical committee first rejected their claim, but then approved of the two transplants as one paired donation, not as two separate donations. This might be a milestone in the practice and potentially lead to more standardized procedures in the future.

As time goes by and word gets around, more and more incompatible pairs enter their data into the database. A handful of already identified pairs for paired donations are currently in different stages of the medical and legal process. The first step taken by Charité Berlin encouraged other hospitals to show interest in conducting paired transplants.

Despite of this recent progress, an efficient kidney exchange program would clearly require a law change in Germany. It would be sufficient to modify the current regulation marginally, by stating that the close personal connection is meant for the pairs entering the pool together and not for the matched pairs."


Here's a link to (and translation of) an op-ed I published in a German newspaper in 2016 urging that the law be amended to allow regular kidney exchange:

German organ transplant law should be amended or reinterpreted to allow kidney exchange: my op-ed in Der Tagesspiegel

And here are all my posts on kidney exchange in Germany.

Saturday, January 22, 2022

Matchup 2022: matching and market design in Vienna, August 25-2

 Here's the announcement and call for papers

Matchup 2022 

MATCH-UP 2022 is the 6th workshop in an interdisciplinary and international workshop series on matching under preferences . It will take place on 25-26 August 2022, hosted by TU Vienna and co-located with MFCS 2022 (47th International Symposium on Mathematical Foundations of Computer Science).

Matching problems with preferences occur in widespread applications such as the assignment of school-leavers to universities, junior doctors to hospitals, students to campus housing, children to schools, kidney transplant patients to donors and so on. The common thread is that individuals have preferences over the possible outcomes and the task is to find a matching of the participants that is in some sense optimal with respect to these preferences. There has been a resurgence of activity in this area in recent years, with online and mobile computing opening up new avenues of research and novel, path-breaking applications.

The remit of this workshop is to explore matching problems with preferences from the perspective of algorithms and complexity, discrete mathematics, combinatorial optimization, game theory, mechanism design, and economics. Thus, a key objective is to bring together the research communities of the related areas. Another important aim is to convey the excitement of recent research and new application areas, exposing participants to new ideas, new techniques, and new problems.

List of Topics

The matching problems under consideration include, but are not limited to:

  • Two-sided matchings involving agents on both sides (e.g., college admissions, medical resident allocation, job markets, and school choice)

  • Two-sided matchings involving agents and objects (e.g., house allocation, course allocation, project allocation, assigning papers to reviewers, and school choice)

  • One-sided matchings (e.g., roommate problems, coalition formation games, and kidney exchange)

  • Multi-dimensional matchings (e.g., 3D stable matching problems)

  • Matching with payments (e.g., assignment game)

  • Online and stochastic matching models (e.g., Google Ads, ride sharing,

  • Other recent applications (e.g., refugee resettlement, food banks, social housing, and daycare)

Invited Speakers