Monday, January 31, 2022

Icknomics: Would more corneas be transplanted if they were called "ocular donations" instead of "eye donations"?

 Here's an article in the Journal of Medical Ethics about framing and language associated with the deceased donation of eye tissue.

Arguments for ‘ocular donation’ as standardised terminology to reduce the ‘ick factor’ of ‘eye donation’ by Katrina A Bramstedt, 

Abstract: This brief report presents the global problem of the shortfall of donor corneal tissue for transplantation, a potential root cause (‘ick factor’ language), and a potential solution (modification of ‘ick factor’ language). Specifically, use of the term ‘eye donation’ is a potential hurdle to ocular tissue donation as it can stimulate the ‘ick factor.’ Verbiage such as ‘ocular (eye tissue)’ could be a method of providing terminology that is less emotive than ‘eye donor’ or ‘eye donation.’ The field of transplantation has experienced terminology shifts over time; for example, ‘cadaver’ has been replaced with ‘deceased donor,’ ‘harvest’ has been replaced with ‘recover,’ and ‘life support’ has been replaced with ‘ventilated.’ Notably, only a small number of regions worldwide are using ‘ocular’ terminology, yet it could be an important step to enhancing the informed consent process and improving donation rates, potentially increasing transplant and optimising patient quality of life for those with treatable blindness."

"While corneal transplants are the most common transplants worldwide, corneal blindness remains a significant health problem due to the lack of donor corneal tissue. Globally, there is only 1 cornea available for 70 that are needed, leaving nearly 13 million patients awaiting transplant.1 In 45% of countries which provide corneal tissue donation services, the system requires explicit consent from the donor and/or their family (opt-in).1 Several studies worldwide have reported high rates of consent refusal2 3 with concern about the ‘ick factor’ (repulsion/disgust response) of ‘eye donation.’2 4


"the field of transplantation has experienced terminology shifts over time; for example, ‘cadaver’ has been replaced with ‘deceased donor,’ ‘harvest’ has been replaced with ‘recover,’ and ‘life support’ has been replaced with ‘ventilated.’11 ‘Ocular’ (of the eyes or vision) is a concise term that could be used for both eye tissue and whole eyes..."

Sunday, January 30, 2022

Chemistry is replacing agriculture in the supply of black market drugs

 The war on drugs is getting more complicated, as chemistry replaces agriculture as a primary source.  This calls for changes in both law enforcement and harm reduction.

Here's a balanced view from the WSJ:

The Once and Future Drug War. During the 50 years the U.S. has battled the narcotics trade, illegal drugs have become more available and potent. But that’s no reason to give up. Governments must adapt and find answers beyond law enforcement  By James Marson, Julie Wernau  and David Luhnow 

"America’s longest war isn’t the 20-year fight in Afghanistan. That struggle is dwarfed by the War on Drugs, started by President Richard Nixon more than 50 years ago and still raging.

"The drug war—which has relied on both law enforcement and the military, at a cost of untold lives and hundreds of billions of dollars—has fared little better than the Afghan campaign. Since Nixon’s declaration of war in 1971, drug use has soared in the U.S. and globally, the range and potency of available drugs has expanded and the power of criminal narcotics gangs has exploded.


"The global spread of synthetic drugs like methamphetamine, fentanyl and synthetic opioids is complicating interdiction—the core of America’s strategy for 50 years.


"Fentanyl has now killed far more Americans than all U.S. conflicts since World War II combined. In the past decade, it has claimed more than a half million lives, a toll that is growing swiftly. The nation was reporting fewer than 50,000 fatal overdoses as recently as 2014. 


"The Biden administration is the first to name “harm reduction” a priority. The White House Office on National Drug Control Policy, which was often run in the past by former generals and law-enforcement officials, is now led, for the first time, by a physician, Dr. Rahul Gupta.


"Europe is also pursuing harm reduction. The U.K., the Netherlands, Austria and others have offered drug testing, often at music events, to reduce the risk of overdosing or poisoning. Switzerland, the U.K., Germany and the Netherlands prescribe heroin to dependent users to cut fatal overdoses and needle sharing.

"Portugal has gone further. It decriminalized all drugs in 2001 amid a surge in heroin use and drug-dependent prisoners. Anyone caught with less than a 10-day supply of any drug is sent to a local commission that includes a doctor, lawyer and social worker for treatment. Overdose deaths have fallen from about 360 a year to 63 in 2019.


"Growing social and legal tolerance of drugs dismays people like Mike Vigil, who had a 31-year career in the DEA, including chief of international operations. He acknowledges that interdiction and law enforcement have not solved the problem. But he says that the U.S. has failed to develop a comprehensive strategy, including investing in down-and-out communities where drug use flourishes and trying to reduce future demand through massive, sustained education programs.


“We aren’t going to be able to arrest our way out of this,” says Mr. Vigil. His frustration is widely shared. “The U.S. has never taken the demand side of things seriously,” says former Mexican President Felipe Calderón."

Saturday, January 29, 2022

Erotic movies versus porn -- times and terms are changing

In a 1964 case, Jacobellis v. Ohio, Supreme Court Justice  Potter Stewart famously declared that it was difficult to define pornography, but that "I know it when I see it " (Less well known is how he continued that sentence: "I know it when I see it, and the motion picture involved in this case is not that.”

But "porn" has now become such a big category that it isn't even clear that the word retains its original repugnance.  A New York Times story that considers its redeeming features is about a film director whose website characterizes her this way: "Female provocateur and porn film director Erika Lust is creating a new world of indie adult cinema" (It turns out that Lust isn't her original family name...)

 Here's the story from the NY Times:

‘There’s Not Just One Type of Porn’: Erika Lust’s Alternative Vision. The Swedish moviemaker thinks pornography can create a society that sees sexuality as myriad and joyful, and where women’s pleasure matters.  By Mary Katharine Tramontana


And here's another story, which features the megasite Pornhub, in Vanity Fair:

XXX-Files: Who Torched the Pornhub Palace?  BY ADAM GOLLNER

"Pornhub, with its undulating ocean of explicit content, is often ranked among the 10 most viewed websites in the world. More Americans use it than use Twitter, Netflix, or Instagram.


"starting in December, a series of legal and P.R. scandals slammed the company. First, a New York Times exposé accused the firm of knowingly hosting child sex abuse materials (CSAM). Antoon denied the charges: “Any suggestion that we allow or encourage illegal content is completely untrue and defies rational reason, from both a moral and business standpoint,” he told me. Still, Canadian senators and MPs called for a criminal investigation. In the uproar, credit card processors suspended payments on the site.


"Forty years ago, debates about porn focused on the idea that the sex industry was inherently dehumanizing and rife with abuse. Activist Andrea Dworkin famously argued that porn was detrimental to women, full stop. But not all second-wave feminists agreed. A vocal faction argued for an erotic-positive approach to rejecting sexual repression. The phrase “pornography is violence against women,” wrote Ellen Willis, an influential pro-sex feminist, “was code for the neo-Victorian idea that men want sex and women endure it.”

"The argument remains as contentious as it is unresolved. This fall, the Times published an op-ed by Michelle Goldberg—“Why Sex-Positive Feminism Is Falling Out of Fashion”—citing a TikTok-based “Cancel Porn” movement. Then again, Cosmo contended that “As we all know, women enjoy porn just as much as guys do.” In fact, an estimated one third of Pornhub’s users are women. And the current feminist perspective on the porn debate might best be summarized by Oxford philosopher Amia Srinivasan in her new book, The Right to Sex: Feminism in the 21st Century: “If a woman says she enjoys working in porn, or being paid to have sex with men, or engaging in rape fantasies, or wearing stilettos—and even that she doesn’t just enjoy these things but finds them emancipatory, part of her feminist praxis—then we are required, many feminists think, to trust her. 


"The most seismic attack on the company came a year ago—in the form of a Nicholas Kristof New York Times op-ed stating that Pornhub was “infested with rape videos. 


"Soon, a merry-go-round of lawsuits started being filed on behalf of underage or nonconsenting victims: an Alabama case invoked the Trafficking Victims Protection Reauthorization Act


"When Pornhub released an app last summer directing museumgoers to classic nude paintings, legal action was threatened by the Louvre and the Uffizi. As one Montreal source put it: “They’re in trouble all over the world.”


"The new crusaders aim to outlaw the commercial sex industry altogether, regardless of how that might affect sex workers, already a marginalized group. The main outcome of credit card bans on Pornhub—which Mickelwait considers an important victory—was that content creators stopped getting paid. The fallout extended to OnlyFans, the booming subscription-based platform that connects users directly with content creators. In August, OnlyFans threatened to remove all “sexually explicit” content, which would have had a chilling effect on free speech, open expression, and private digital commerce. Under pressure, the company reversed that decision


"While the internet continues its Wild West resistance to law and order, porn keeps getting ever more mainstream. (When Facebook and Instagram both went down one day last fall, for instance, Pornhub saw a 10.5 percent traffic spike.) Meanwhile, making porn has become America’s “side hustle,” Ruby told me, describing an expanding movement of makers selling their sexuality online. “People figured out that they could just document that part of their lives and earn an extra two or three thousand dollars a month and feed their families.” Pornhub, OnlyFans, and other digital portals played an integral part in that phenomenon."

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.


Update: the paper appears as

Grenet, Julien, YingHua He, and Dorothea Kübler. "Preference Discovery in University Admissions: The Case for Dynamic Multi-offer Mechanisms." Journal of Political Economy, volume 130, number 6, June 2022, 1427-1476,

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

Friday, January 21, 2022

Black market marijuana coexists with legal marijuana in Oregon, and competes with it in California

In a growing number of U.S. states, it is legal to grow and sell marijuana. But the price remains highest in the states where it is illegal, and so black markets persist alongside legal markets. 

Politico has the story:

‘Talk About Clusterf---’: Why Legal Weed Didn’t Kill Oregon’s Black Market. Legalization was supposed to take care of the black market. It hasn’t worked out that way.  By NATALIE FERTIG

"Over the last two years, there’s been such an influx of outlaw farmers that southern Oregon now rivals California’s notorious Emerald Triangle as a national center of illegal weed cultivation. Even though marijuana cultivation has been legal in Oregon since 2014, Jackson County Sheriff Nate Sickler says there could be up to 1,000 illegal operations in a region of more than 4,000 square miles. The Oregon Liquor and Cannabis Commission, which oversees the state’s $1.2 billion legal cannabis industry, estimates the number of illicit operations is double that.


"What is happening in the woods of the southern Oregon represents one of the most confounding paradoxes of the legalized marijuana movement: States with some of the largest legal markets are also dealing with rampant illegal production — and the problem is getting worse. Oklahoma, where licenses to cultivate medical marijuana are some of the easiest to get in the nation, has conducted more than five dozen raids on illicit grows since last April. In California, meanwhile, most of the state continues to purchase cannabis from unlicensed sources — straining legal operators already struggling with the state’s high taxes and fees.


"One of the underlying promises for legalizing cannabis was that legalization would make the illegal drug trade, with all its attendant problems of violent crime and money laundering, disappear. But 25 years into the legalization movement, as 36 states have adopted some form of legalized marijuana, the black market is booming across the country. Legal states such as Oregon and California — which have been supplying the nation for nigh on 60 years — are still furnishing the majority of America’s illegal weed.


"Oregon’s weed is some of the cheapest in the nation, and Oregonians predominantly purchase weed from licensed dispensaries. Economist Beau Whitney estimates that 80-85 percent of the state’s demand is met by the legal market. But most of the illicit weed grown in southern Oregon is leaving the state, heading to places where legal weed is still not available for purchase such as New York or Pennsylvania — or where the legal price is still very high, like Chicago and Los Angeles. In Illinois, which legalized medical marijuana in 2013, only about a third of the demand for cannabis is satisfied by legal dispensaries, according to Whitney. Differences in tax rate and regulations plays the major role in differences from state to state, Whitney explains.


And in California it appears that high taxes on the legal market allow the black market to exist alongside. NBC has the story:

Craft cannabis industry in California is 'on the brink of collapse,' advocates say. Small cannabis growers and operators say the state's hefty taxes are shutting them out despite promises to expand the industry and make it more inclusive.  By Alicia Victoria Lozano

"Last month, marijuana companies warned Newsom in a letter that immediate tax cuts and a rapid expansion of retail outlets were needed to steady an increasingly unstable marketplace shaken by illicit dealers and growers.

"More than two dozen cannabis executives and legalization advocates signed the letter after years of complaints that the heavily taxed industry is unable to compete with the widespread illegal economy, which offers far lower consumer prices and has double or triple the sales of the legal market."

Thursday, January 20, 2022

Vacancy chains in urban housing

 Vacancy chains occur not just in labor markets, but also in housing markets. (Earlier this week I wrote about housing chains for hermit crabs that result from evictions.)  A vacancy chain in a housing market can be thought of as a moving chain: someone moves into a vacant house or apartment (perhaps a newly constructed one), and someone else moves into the home they vacated, and so on, until the chain ends when a person who was in some different market (e.g. in rental housing, or in a distant location) moves into the last identifiable home in the chain.

Here are two papers that explore what happens when newly constructed housing is relatively expensive. They find that the chain often reaches much more moderately priced housing, i.e. adding to the stock of expensive housing also makes more affordable, existing housing available to new occupants.

The first paper draws on data from a dozen American cities (from Atlanta to San Francisco):

The effect of new market-rate housing construction on the low-income housing market, by Evan Mast, Journal of Urban Economics, Available online 27 July 2021,

Abstract: I illustrate how new market-rate construction loosens the market for lower-quality housing through a series of moves. First, I use address history data to identify 52,000 residents of new multifamily buildings in large cities, their previous address, the current residents of those addresses, and so on for six rounds. The sequence quickly reaches units in below-median income neighborhoods, which account for nearly 40 percent of the sixth round, and similar patterns appear for neighborhoods in the bottom quintile of income or percent white. Next, I use a simple simulation model to roughly quantify these migratory connections under a range of assumptions. Constructing a new market-rate building that houses 100 people ultimately leads 45 to 70 people to move out of below-median income neighborhoods, with most of the effect occurring within three years. These results suggest that the migration ripple effects of new housing will affect a wide spectrum of neighborhoods and loosen the low-income housing market.


A more recent working paper draws on data from metropolitan Helsinki and reaches similar conclusions:

Bratu, Cristina and Harjunen, Oskari and Saarimaa, Tuukka, City-wide Effects of New Housing Supply: Evidence from Moving Chains (August 31, 2021). VATT Institute for Economic Research Working Papers 146, Available at SSRN: or

Abstract: We study the city-wide effects of new, centrally-located market-rate supply using geo-coded total population register data from the Helsinki Metropolitan Area. The supply of new market rate units triggers moving chains that quickly reach middle- and low-income neighborhoods and individuals. Thus, new market-rate construction loosens the housing market in middle- and low-income areas even in the short run. Market-rate supply is likely to improve affordability outside the sub-markets where new construction occurs and to benefit low-income people.



Vacancy chains in housing for hermit crabs   

Blum, Y., A.E. Roth, and U.G. Rothblum "Vacancy Chains and Equilibration in Senior-Level Labor Markets," Journal of Economic Theory, 76, 2, October 1997, 362-411.

Wednesday, January 19, 2022

Dialysis provider DaVita enters the transplant space

 Here's the press release:

DaVita Acquires MedSleuth, Deepens Efforts to Improve Transplant Experience. Transplant software company helps DaVita bolster its presence along the kidney care journey

" DaVita Inc. today announced its acquisition of transplant software company MedSleuth. Working with transplant centers across the U.S., MedSleuth aims to create greater connectivity among transplant candidates, transplant centers, physicians and care teams to help improve the experience and outcomes for kidney and liver transplant patients.

"With this acquisition, DaVita deepens its efforts to fuel transplant innovation, underscoring its commitment to improve care at every stage and setting along a patient's kidney care journey.

"Kidney transplantation is a life-changing option for most people with kidney failure, one that's limited today by supply and complexity," said Javier Rodriguez, CEO for DaVita. "MedSleuth has built a powerful platform that can help increase patients' access to transplantation. We're looking forward to supporting the team to accelerate innovation and help streamline the transplant process for transplant candidates, transplant centers, physicians and care teams."

"From lack of supply to meet the demand to understanding and staying on top of the complex process from workup to wait list to transplant, the U.S. transplant system can be complicated to navigate.

"MedSleuth's innovative software can help not only streamline the process of evaluating candidates and keep them active on the waitlist but may also help increase the rate of transplantation through living donation. The software can also make it easier for transplant candidates' doctors and care teams to help support them along the transplant journey.

"BREEZE™, MedSleuth's flagship product, helps remove certain barriers for potential kidney and liver donors and recipients by remotely gathering relevant clinical and demographic information and sharing it with participating transplant centers—effectively streamlining the transplant process, from candidate evaluation through donor and recipient follow-up.

"MATCHGRID™, MedSleuth's paired exchange platform, uses optimization algorithms to find chains for paired donation. This helps transplant center clinicians rapidly match living organ donors with recipients who have willing, healthy but incompatible donors."

HT; Martha Gershun

Tuesday, January 18, 2022

Evictions and coalitions in the housing market of hermit crabs--shell trafficking in the wild

 I've previously blogged about the observation that hermit crabs, who live in the shells of other animals and have to get new shells as they grow, sometimes engage in chains of exchange, that resemble kidney exchange chains, or vacancy chains in labor markets.

In particular, they resemble kidney exchange chains initiated by a deceased donor, in this case initiated by an empty shell.

 Here's a new article about hermit crabs which reports that they also engage in something that looks like organ trafficking, with a hermit crab being forcibly removed from its shell by two smaller crabs acting in concert, so that one of them may occupy the now vacant shell while the other moves into the shell of its partner in crime.

Laidre, Mark E. "The Architecture of Cooperation Among Non-kin: Coalitions to Move Up in Nature’s Housing Market." Frontiers in Ecology and Evolution (2021): 928.

"Coalitions typically involve two individuals (a pair), with a third individual being the target that the two-member coalition seeks to evict from its shell (Figure 1). Both members of the coalition have shells of their own, but these individuals and their shells are virtually always smaller than that of the target individual and its shell. Sometimes, based on the commotion and struggle generated during an attempted eviction, additional individuals—beyond the target and the core two-member coalition—are attracted to the area. These additional individuals—referred to as “third parties” or “bystanders”—are not part of the actual coalition, since they do not help at all to evict the target. Generally, third parties simply wait in the vicinity and sometimes position themselves in a social chain, which emanates from the back of the shell of one or both of the coalition members (Figure 2). This positioning in a social chain enables third parties to indirectly benefit, since in the event an eviction succeeds, it can catalyze a succession of back-to-back shell swaps (see Laidre, 2019a). Third parties are thus, in effect, “free riders” (Sigmund, 2010), since their positioning around the coalition offers no advantage whatsoever to the coalition itself as it works to evict the target. Indeed, whether third parties are positioned in a chain or not, they merely wait, performing no pulling actions and never adding any strength or providing any help to the two-member coalition. Interestingly, based on precisely where third parties position themselves, some may potentially even undermine the coalition (see below), effectively acting not merely as “free riders” but as “cheaters” (Sigmund, 2010). Finally, if too many bystanders accumulate, it can lead to chaotic jockeying and repositioning, with the original coalition separating.

"Whether with third parties present or not, the two members of the coalition attempt to physically evict the target. The target remains flipped on its back (i.e., with the dorsal side of its shell on the ground) and the opening of the target’s shell faces upward, allowing both coalition members to use their claws and legs to grab at and pull the anterior portion of the target’s body. As the coalition forcibly pulls, the target attempts to resist by clinging inside its shell. Typically, the two coalition members both pull simultaneously; though at times the two may alternate attempts at pulling, each doing so sequentially as one or the other member briefly rests. Both members of a coalition appear strongly involved, in terms of time and effort. Yet coalitions are not always successful. In some cases, one or both coalition members may give up; or the target individual may manage to flip itself over, escape from being pinned down, and run away. If a coalition is successful at evicting the target, the time till eviction occurs can vary widely, from just minutes up to hours (Laidre, personal observation). Once a coalition is successful and the target individual is evicted from its shell, then the evictee is pushed to the side and remains naked and shell-less as one of the coalition members moves into its now empty shell."



Saturday, July 21, 2012

Monday, January 17, 2022

Honoring Milgrom and Wilson at the ASSA meetings in January (video)

 The video is at the link, there are four ten minute discussions, followed by brief responses by Paul and Bob. 

My discussion of Bob Wilson begins at around 27:20, and my final words to him were "Bob: you saw and demonstrated the future of game theory in economics, earlier and more clearly than anyone else.  We’re all lucky to know you."

AEA Nobel Laureate Address Honoring the 2020 Nobel Laureates Paul R. Milgrom (Stanford University) and Robert B. Wilson (Stanford University)
January 8, 2022 at 2:30 PM ET
View Recording

Presiding: Christina D. Romer, University of California-Berkeley

Susan Athey
Stanford University
Topic: Honoring Paul R. Milgrom
Bengt Holmstrom
Massachusetts Institute of Technology
Topic: Honoring Paul R. Milgrom
Alvin Roth
Stanford University
Topic: Honoring Robert B. Wilson
Srihari Govindan
University of Rochester
Topic: Honoring Robert B. Wilson

Sunday, January 16, 2022

Centralized Student Choice and Assignment Systems around the world

 Christopher Neilson at Princeton has launched a web site aimed at organizing information on school choice around the world. The site opens with an ambitious world map, and it looks like there is still plenty of room for contributions from people with information on school choice systems wherever they are.

Centralized Student Choice and Assignment Systems

"Centralized Choice and Assignment Systems have been implemented in many countries and different settings, in an adoption trend that is likely to continue.

"With support from the Industrial Relations Sector at the Economics Faculty of Princeton University, this project aims to document the adoption trend and the large heterogeneity in implementation practices, with the objective of fostering further research into the different systems and identifying best practices for different contexts.

"The team has worked intensively in collecting and organizing the data. Nonetheless, the project is very ambitious and information about the different systems can be improved and needs to be updated. Therefore, with this challenge in mind, this webpage has been created to be able to share the data with the research and policy making communities around the world, and to invite everyone to contribute to the effort, suggesting edits and additional information that will improve upon the data collected."

Saturday, January 15, 2022

Neighborhoods matter in school choice

 Here's a working paper that observes that assignments of places to pre-kindergarten students remains strongly influenced by where the children live, even in the presence of a school choice system.  I.e. many pre-kindergarten students go to neighborhood schools.

Distance to Schools and Equal Access in School Choice Systems, by Mariana Laverde

 Abstract: This paper studies the limits of school choice policies in the presence of residential segregation. Using data from the Boston Public Schools choice system, I show that white prekindergarteners are assigned to higher-achieving schools than minority students, and that cross-race school achievement gaps under choice are no lower than would be generated by a neighborhood assignment rule. To understand why choicebased assignments do not reduce gaps in school achievement, I use data on applicants’ rank-order choices to estimate preferences over schools, and consider a series of counterfactual assignments. I find that half of the gap in school achievement between white and Black or Hispanic students is explained by minorities’ longer travel distance to high-performing schools. Differences in demand parameters explain a smaller fraction of the gap, while algorithm rules have no effect."

From the conclusions:

"The salience of travel costs shows a first-order channel for why neighborhoods matter, highlighting how the effective provision of public goods can be affected by geography at very granular levels. In some way these results are not surprising. Most, if not all, of the papers that study school demand agree that distance is a key factor in parental choices. This paper takes this observation one step further and quantifies how much this cost limits the effectiveness of school choice policies in equalizing access to high-achieving schools. The results show that even in a generous choice environment where parents face minimal restrictions to their choices and free transportation is provided, distance can contribute greatly to inequity and that the design of the assignment algorithm can do little to break structural place-based inequities. This finding is not only relevant for the pre-kindergarten population. Not only we know that early investments can have lasting impacts on adult outcomes, but also, choice systems are typically designed to grandfather students into subsequent grades within a school. Then, even if travel costs are lower for older children, early assignments are held for several years after. In consequence, inequities in pre-kindergarten extend well after that period."

Friday, January 14, 2022

Experimental Economics in the Tradition of John Kagel (video)

 In October there was an in-person celebration of John Kagel, which I was delighted to participate in, in Tucson, Arizona. (It was my first in-person conference since the beginning of the Covid pandemic, during a brief window of optimism.) Now it's been posted on YouTube by the hosts, at the Economic Science Lab of the University of Arizona:

Keynote lecture of Professor Alvin Roth at the Workshop in Honor of John Kagel, Tucson, Arizona, October 2021

My talk was called Experimental Economics in the Tradition of John Kagel, and I began by explaining this photograph, which has John in the middle.

I eventually focused on how the following experiment helped shape a good deal of practical market design:

Kagel, John H. and A.E. Roth, "The dynamics of reorganization in matching markets: A laboratory experiment motivated by a natural experiment," Quarterly Journal of Economics, February, 2000, 201-235.

And I concluded by giving John some unnecessary advice as he embarks on his tenth decade.

You can see more from the 2021 North-American Economic Science Association Conference (including the above video) here.

Thursday, January 13, 2022

Black market supply chains, Persian gulf stories

 Supply chains around the world are reacting to disruptions caused by Covid and other things. And those are mostly uncontroversial, uncontested legal supply chains.  For black markets things are even tougher. Here are two stories, about oil and arms, from the Persian gulf. Both are from the WSJ:

Smuggled Iranian fuel and secret nighttime transfers: Seafarers recount how it’s done  By Katie McQue

"The secret transfers usually take place at night to evade detection by regional coast guards. The ships anchor in the Persian Gulf just outside the territorial limits of the United Arab Emirates, and then, individually, small boats carrying smuggled Iranian diesel shift their loads to the waiting vessels, according to seafarers who have witnessed the trade.

It is a big chain, with fishing boats sailing up to give diesel to a waiting tanker. It takes four to five days because boats come one by one,” said a 27-year-old Indian seafarer, who spoke on the condition of anonymity for fear of reprisals. He said he had been employed by a Dubai-based shipping company that smuggled Iranian fuel to Somalia.


"In addition to the nighttime transfers at sea, Iranian diesel bound for international markets is exported on tankers setting sail from Iran with the origin of the shipment forged to make it look as though it came from Iraq or the UAE, according to a third seafarer and three experts in security and energy affairs.

"Because of the profit margins, this trade was highly lucrative even before the United States pulled out of the nuclear deal. Iran has some of the world’s cheapest fuel prices thanks to very low production costs, heavy government subsidies and a weak currency. But the reimposed economic sanctions have given this business a further boost as smugglers seek to evade restrictions on Iranian oil exports. 


Iran Navy Port Emerges as Key to Alleged Weapons Smuggling to Yemen, U.N. Report Says  By Benoit Faucon  and Dion Nissenbaum

"Thousands of rocket launchers, machine guns, sniper rifles and other weapons seized in the Arabian Sea by the U.S. Navy in recent months likely originated from a single port in Iran, according to a confidential United Nations report that provides some of the most detailed evidence that Tehran is exporting arms to Yemen and elsewhere.

"The draft report prepared by a U.N. Security Council panel of experts on Yemen said small wooden boats and overland transport were used in attempts to smuggle weapons made in Russia, China and Iran along routes to Yemen that the U.S. has tried for years to shut down. The boats left from the Iranian port of Jask on the Sea of Oman, the U.N. report said, citing interviews with the boat’s Yemeni crews and data from navigational instruments found on board."

Wednesday, January 12, 2022

New York State bills propose to be more generous to living donors

 Frank McCormick points out an op-ed in the Albany Times Union newspaper, coathored by a medical ethicist and a kidney donor:

Commentary: Kidney donors are heroes. We need to treat them that way.  by Arthur Caplan and Sammy Beyda

"if just a small fraction of Americans donated their kidneys, the 100,000- person organ waitlist might be eliminated. It stands to reason, then, that we should enact some sort of legislation to incentivize kidney donation, but many have argued against paying Americans to sell their kidneys, and federal law prohibits such sales.

"However, there is another way to proceed that preserves core transplant donation values while seeking to increase living kidney donation. A new bill in the state Legislature would fully compensate New Yorkers for the costs associated with living donation, and another would offer free health insurance to anyone who donates.


"What the New York legislation understands is that kidney donation is an act of commendable public service, one that deserves all the honors that we give to public servants like soldiers, nurses, EMTs, and firefighters. Instead of trying to pay donors in a market system that would treat donation as a transaction, we should properly treat donors as what they are: heroes trying to help those in dire need.


"There’s a real opportunity for New York to lead the nation in stamping out death and disability due to kidney disease by taking bold steps to increase living kidney donation. As a bioethicist and a kidney donor, we recognize that now is the time to act. State lawmakers should prioritize these bills and provide a safety net for those willing to be donors. You should not lose money or risk debt to be a hero."


Here's a paper about treating donors as heroes:

Niederle, Muriel and Alvin E. Roth, “Philanthropically Funded Heroism Awards for Kidney Donors?, Law & Contemporary Problems, 77:3, 2014, 131-144.  )


And as I've noted before, kidney disease is persistently among the top ten causes of death in the US and around the world, with over 50,000 deaths in 2020 in the U.S.

Saturday, April 17, 2021

Tuesday, January 11, 2022

First pig-to-human heart transplant (and some background on the trials with non human primates)

 Xenotransplants, of pig organs into humans, may be closer than I thought. A dramatic step was taken last Friday when a pig heart was successfully transplanted into a man who was still being kept alive by the heart yesterday when the NY Times reported it.  Following the news story, I'll link to a recent summary of the increasing success of transplanting pig hearts into non-human primates.  In the near term, the idea is that a pig heart might keep a patient alive until a human organ becomes available.

Here's the NY Times story:

In a First, Man Receives a Heart From a Genetically Altered Pig. The breakthrough may lead one day to new supplies of animal organs for transplant into human patients.  By Roni Caryn Rabin

"A 57-year-old man with life-threatening heart disease has received a heart from a genetically modified pig, a groundbreaking procedure that offers hope to hundreds of thousands of patients with failing organs.

"It is the first successful transplant of a pig’s heart into a human being. The eight-hour operation took place in Baltimore on Friday, and the patient, David Bennett Sr. of Maryland, was doing well on Monday, according to surgeons at the University of Maryland Medical Center.

It creates the pulse, it creates the pressure, it is his heart,” said Dr. Bartley Griffith, the director of the cardiac transplant program at the medical center, who performed the operation.

It’s working and it looks normal. We are thrilled, but we don’t know what tomorrow will bring us. This has never been done before.


And here's a just-published paper that gives some background:

Shu, S., Ren, J. & Song, J. Cardiac xenotransplantation: a promising way to treat advanced heart failure. Heart Fail Rev 27, 71–91 (2022).

Abstract: Cardiac xenotransplantation (CXTx) might be a promising approach to bridge the gap between the supply and demand of a donor heart. The survival of cardiac xenograft has been significantly extended in pig-to-nonhuman primate (NHP) CXTx, with records of 195 days and 945 days for orthotropic and heterotopic CXTx, respectively. ...



Sunday, December 5, 2021

Monday, January 10, 2022

The price of nails since 1695

 If your friends and relatives wonder why economists write about the things we do, this interesting paper should reassure them that someone is minding the economics store and thinking deeply about prices...


NBER Working Paper 29617,

Abstract: This paper focuses on the price of nails since 1695 and the proximate source of changes in those prices. Why nails? They are a basic manufactured product whose form and quality have changed relatively little over the last three centuries, yet the process for producing them has changed dramatically. Accordingly, nails provide a useful prism through which to examine a wide range of economic and technological developments that touch on multiple areas of both micro- and macroeconomics. Several conclusions emerge. First, from the late 1700s to the mid 20th century real nail prices fell by a factor of about 10 relative to overall consumer prices. These declines had important effects on downstream industries, most notably construction. Second, while declining materials prices contribute to reductions in nail prices, the largest proximate source of the decline during this period was multifactor productivity growth in nail manufacturing, highlighting the role of the specialization of labor and re-organization of production processes. Third, the share of nails in GDP dropped back from 0.4 percent of GDP in 1810—comparable to today’s share of household purchases of personal computers—to a de minimis share more recently; accordingly, nails played a bigger role in American life in that earlier period. Finally, real nail prices have increased since the mid 20th century, reflecting in part an upturn in materials prices and a shift toward specialty nails in the wake of import competition, though the introduction of nail guns partly offset these increases for the price of installed nails.

"nails are ideal for this analysis because there has been relatively little change in the product itself (unlike the production of computing power or lighting), thereby greatly simplifying the task of adjusting for changes in quality over time.


" In 1810 (the earliest year for which I could assemble necessary data), the use of nails in the US (measured as production plus imports minus exports) was about 0.4 percent of nominal GDP as shown in Figure 1. To put this share into perspective, in 2019 household purchases of personal computers and peripheral equipment amounted to roughly 0.3 percent of GDP and household purchases of air travel amounted to about 0.5 percent. That is, back in the 1700s and early 1800s, nails were about as important in the economy as computers or air travel purchased by consumers are today. "