Thursday, November 30, 2023

UNOS ends its liver exchange pilot program

UNOS has shuttered it's liver exchange pilot program, after less than a year, without having performed any liver exchange transplants. (My understanding is that this wasn't part of UNOS's OPTN contract, but part of its activities as a private company.)

A colleague forwarded me this announcement:

"After careful consideration and evaluation, we regret to announce the discontinuation of the UNOS Liver Paired Donation Pilot Program (LPDPP).

The UNOS LPDPP was launched with the noble goal of matching candidates in need of a liver transplant with living donors from across the United States. Top-tier transplant programs from around the country participated in the program, entering pairs to be matched for transplantation.

 Despite the enthusiasm and dedication of the UNOS LPDPP Steering Committee, participating hospitals, a visionary funder and UNOS Labs staff, we must acknowledge that the program faced significant challenges. Regrettably, no matches were made, and no transplants occurred during the course of the pilot.

 This decision to discontinue the program is a result of several factors, primarily the depletion of funding allocated to the pilot and other barriers to widespread adoption. While practical constraints have led us to this difficult decision, we are still committed to uncovering key insights that may help future efforts toward a national liver paired donation program and apply to other challenges facing the organ donation and transplant community.

 We would like to express our heartfelt gratitude to the Steering Committee, participating transplant programs’ staff, candidates and donors who agreed to be entered and the generous living liver recipient who funded this endeavor. Your dedication to saving lives through organ transplantation is truly commendable. These efforts have yielded valuable data and insights that will allow our community to continue to advance.

 While this chapter may be closing, our commitment to increasing the number of lives saved through organ donation and transplant remains unwavering. We will continue to explore innovative ways to improve access to organ transplants for those in need. We will be doing more investigation into the program’s barriers to success, unexpected challenges and opportunities for improvement, and we plan to share our discoveries with the community so we may all learn from the results.

 The program will officially end November 30, 2023, with the last match run on September 30, 2023."



Friday, January 27, 2023

Liver exchange pilot program at UNOS

see also, from UNOS:

and this, from Medscape:

"It is possible that the 1-year pilot program could run without performing any paired transplants, but that's unlikely if multiple pairs are enrolled in the system, the spokesperson said. At the time of this story's publication, the one enrolled pair are a mother and daughter who are registered at the UCHealth Transplant Center in Colorado.
"The pilot program requires that the donor bring one support person with them if they need to travel for the surgery, but undergoing major abdominal surgery from a transplant team they are not familiar with may be stressful, said Peter Abt, MD, a transplant " at the Hospital of the University of Pennsylvania and the Children's Hospital of Philadelphia. "That's a big ask," he said, "and I'm not sure many potential donors would be up to that."

"John Roberts, MD, a transplant surgeon at the University of California, San Francisco, agreed that the travel component may put additional stress on the donor, but "if it's the only way for the recipient to get a transplant, then the donor might be motivated," he added.
"Leishman agreed that the travel aspect appears to one of the greatest barriers to participants entering the program but noted that a goal of the pilot program is to understand better what works — and what doesn't — when considering a liver paired donation program on a national scale. "[Our] steering committee has put together a really nice framework that they think will work, but they know it's not perfect. We're going to have to tweak it along the way," she said."

Wednesday, November 29, 2023

Repugnant sales of art: deaccessioning, in Switzerland

 "Deaccessioning" is a repugnant transaction in the art world, in which it's often considered acceptable to sell art only to finance the purchase of other art, and not to keep a museum from going bankrupt.  I've written about this in the U.S. context, but it's an international phenomenon.

The NY Times has the story, from Switzerland:

Swiss Museum in Financial Straits Sells Three Cézannes for $53 Million. Museum Langmatt said the sales were necessary to keep its doors open. Critics had said they violated industry guidelines on when a museum should sell off parts of its collection.

"The Foundation Langmatt’s decision to sell the Cézannes earned wide criticism before the auction. The Swiss branch of the International Council of Museums, which said the sale was a clear breach of its guidelines for de-accessioning from museum collections, called for the paintings to be withdrawn.

Tuesday, November 28, 2023

"Professional blood donors" in India (where paying blood donors is illegal)

 India allows only unpaid blood donation, from altruistic donors or from "replacement donors" who are friends or relations of particular patients in need of blood (who must procure it before receiving it). There is a severe blood shortage, some of which is filled by black market "professional" blood donors, who are paid to pretend to be unpaid replacement donors.

Here's a story from the Indian news service Quint:

Out for Blood: Why Are Many Indians Forced To Seek 'Professional Blood Donors'? Although it is illegal, why is there a thriving market for paid blood donors in India?  by ANOUSHKA RAJESH and MAAZ HASAN

"Donating blood in exchange for money was banned in India in 1996. However, paying 'professional blood donors' to meet this requirement is still fairly common.


"To see how easy it would be to 'arrange' a paid blood donor, FIT went to one of the busiest government hospitals in Delhi.


"All leads – from vendors to patient families and bootleg pharmacists – point us to Ashok (name changed). He sits, surrounded by 4-5 men, and is guarded when we make inquiries.

"He begins with the following line of questioning: 'Where is our patient admitted?  What surgery do they need?  Why couldn't we just get friends and relatives to donate?

"Posing as a patient's friend, the FIT reporter gives him preplanned answers. In the emergency ward.  He had an accident and needs surgery on his leg.  I donated blood a month ago. He has no family here, and everyone else we reached out to has refused.

"Only when he's satisfied with the answers, he says he would be able to 'arrange boys' by the next day, and that it would cost between Rs 3,500 to Rs 4,000.


"According to the Ministry of Health and Family Welfare, India's annual requirement for blood is around 1.5 crore units per year, while in reality, only around 1 crore units are available.

"This gap in supply and demand of blood poses a major public health crisis in the country. For example, around 70 percent of postpartum hemorrhage (PPH)-related deaths in India are due to lack of immediate availability of blood.


"The paid donors are generally young boys, between the ages of 20 and 25, from very poor backgrounds," says Dr Dubey. ""This will no doubt be detrimental to their health," he adds. Moreover, if caught, they face the risk of jail time.

"The protocol is to ask every donor a set of questions before we take their blood. "If they seem suspicious, we ask them questions like, 'how are you related to the patient?', 'what is the patient's name?', and 'what surgery are they having?', to sus them out. If we get enough proof, we either defer them, or hand them over to the cops," Dr Priyansha Gupta, PG resident, Public Health, who has worked in Delhi's AIIMS blood bank in the past.

"What, then, happens to the families who desperately need blood when their donors are deferred?

"Dr Dubey says they are referred to the social workers attached to the hospital to get them help.


"But you have to understand, blood is a scarce commodity, and there's only so much we have."


Here's a story from the Hindustan Times (in 2022), which begins with some relevant background (before debunking myths that lead to a shortage of voluntary donors):

Common myths on blood shortage in India  "The article is authored by Dr Parth Sharma, researcher, Ranita De, researcher in Lancet Citizen's Commission on Reimagining India’s Health System and Dr Vaikunth Ramesh."

"The shortage of blood products has been a major public health problem in India. It is estimated that nearly 12,000 people lose their lives every single day due to the lack of blood products. Supporting a population of 1.4 billion, the present blood transfusion service is fragmented with a little over 3,700 blood centres of which about 70% are located in eight states only. As of 2020, 63 districts in India do not have a blood centre. Space crunch and a burgeoning population have led to the establishment of health care facilities without blood centres on their premises, which in turn depend on nearby blood or storage centres for access to safe blood.

"Unfortunately, India has one of the largest shortages of blood supplies globally, while several diseases requiring blood transfusions are on the rise.

"A recent study by Joy Mammen, et. al. estimated the shortage to be around 2.5 donations per 1,000 eligible donors which equals a shortage of 1 million units. Blood products are required not only for surgeries but also for patients suffering from various medical conditions causing severe anaemia. At present, the source of donated blood is a combination of voluntary donors and replacement donors. Although professional donors are forbidden by law, they still continue to persist in our system under the guise of replacement donors. Voluntary non-remunerated donors, who donate based on altruism and a sense of doing greater good for the community, unfortunately, account for only 80% of the donors in India.


HT: I was directed to the above links from the Indian posting

India Policy Watch #2: Regulating SoHO  by Pranay Kotasthane, which was in part about the recent move in the EU to further restrict payment for Substances of Human Origin (SoHO), as discussed in

Saturday, November 4, 2023

Monday, November 27, 2023

Banks boycott sex workers even for legal kinds of sex work

 Repugnance isn't erased by legality. Workers in morally contested, repugnant markets may be boycotted by banks even when their work is legal.  Marijuana sellers in states where marijuana sales are legal run into this problem because Federal law still prohibits such sales, but sex workers in legal industries (video sex, porn) and even prostitution in Nevada often can't keep bank accounts, even personal (i.e. non-buisiness) accounts.

The NYT has the story:

Sex Workers Have Been Shunned by Banks, Even When Their Work Is Legal. Financial service companies often avoid what they deem high-risk industries like adult entertainment. When workers lose their accounts, they are left with few options.  By Tara Siegel Bernard

“Despite being a legal establishment, there is, of course, still a stigma attached to the work,” Ms. Cummins, 74, said from Wells, Nev., the only state where prostitution is legal in certain counties. “There is no bank in Nevada that will lend money to a brothel."


"Workers in sex-related industries — whether in a brothel or a strip club or selling sexually explicit videos online — often risk their safety and face social and employment discrimination. But a lesser-known struggle is that it’s often difficult to maintain a basic bank account and other financial relationships that most people take for granted.


"Financial institutions are responsible for monitoring the nation’s cash flow for potential criminal activities, including human trafficking and money laundering. In the process they’ve also become quasi-law enforcement, making life-altering calls on who can keep banking and who cannot, based on their own calculus about what kind of risk is worth taking.

But without bank accounts, people are unable to accomplish the most basic of financial tasks: collecting, spending and saving their earnings. Once banished from mainstream bank accounts and everyday financial apps Americans have come to rely on, sex workers are left with fewer, and often less attractive, options — turning to crypto, for example, or being forced to rely on others to hold their cash, opening them up to exploitation. 

Sunday, November 26, 2023

Interview with Vernon L. Smith by Sami Al-Suwailem

 Here's an interview with Vernon Smith, in which he comments on the history of economics and his place in it.

Interview with Vernon L. Smith by Sami Al-Suwailem 

"Smith was born in 1927 in Wichita, Kansas. He received his bachelor’s degree in electrical engineering at Caltech in 1949, an M.A. in economics from the University of Kansas, and a Ph.D. in economics from Harvard University in 1955.


"GL: In your recent book, Economics of Markets, coauthored with Sabiou Inoua, you argue (convincingly, I’d say) that “markets succeeded where theory failed.” Does that imply that economic (neoclassical) theory failed to study real-world markets well enough?

"VS: It’s more that they failed to study them at all and, in particular, failed to model price formation or price discovery in market processes.


"Walras not only failed to model price discovery but gave us a mechanism that required price mysteriously to be given, then used to model price change depending on the sign of excess demand. This diverted theorists from modeling price discovery and, we believe, created the illusion of progress, but it was more appropriately considered a regress occasioned by marginal analysis, which helped not a wit to address the fundamental task.


"GL: In your work, you argue that competitive equilibrium can be quickly achieved under very reasonable experimental conditions for consumption goods, but that this is not the case for assets where speculation may substantially distort the outcomes. Economic theory seems to pay no attention to this important difference. Why is that?

"VS: It is because standard theory tends to be insensitive to close observation: Item A is purchased in preference to item B if and only if U(A) > U(B), a theory that makes no advance prediction but rather concludes only that if A is bought rather than B it must have had higher utility value.


"In consumer markets, buyers attempt to buy cheap, constrained by their maximum wtp private value. Sellers try to sell dear but are limited by their minimum willingness-to-accept (wta) costs.

"The problem with asset markets is that they have a value-in-use like any consumer good but also a value-in-resale. This sets up a conflict that has to get resolved before an asset market can settle into any sort of equilibrium.

"All economic stability arises in consumer markets, while all instability arises in asset markets for re-tradable goods. Fortunately, about 75% of private products cannot be re-traded, causing great stability.

"GL: The Nobel Prize in Economics was awarded in 2012 to Lloyd S. Shapley and Alvin Roth for their work on market design. How do you see the relationship between these two branches, market design and experimental economics?

"VS: They are closely and intimately related. Indeed, my work in market design was part of my recognition in 2002, and was part of my presentation in 2001 at the Nobel Conference on Experiments in Economics, the year prior to the award."

Saturday, November 25, 2023

Memorial service for Vic Fuchs

 Yesterday, at Etz Chayim Synagogue,  Palo Alto.

Here is my brief eulogy:

Vic was the patriarch of a clan, and a man of wide and old friendships. He was, by the way, also a brilliant, erudite, compassionate economist.

Emilie and I were among his new friends. In 2013 we bought a house down the hill from Vic, and held an open house; he came over, carrying his own chair-back, and was the life of the party.  In those days he used to reply to questions about how he was doing with a joke: “I’m in perfect health—my psychiatrist says it’s all in my body.”

That joke got less funny as his body continued to betray him, and after a while he stopped telling it.

When he joined us for dinner, he and Emilie would negotiate the menu. (He was a fussy eater, who liked his food very plain).

In 2016, when Vic joined us to watch one of the debates among Democratic primary candidates for president, he couldn’t contain himself when they discussed health care, and I gave him a lift home before the debate concluded, so he could write an op-ed. He was still in the game.

During Covid, he stopped leaving his house except to go to the doctor. As his mobility declined, our visits migrated from his patio, to the downstairs living room, and eventually up the half flight of stairs to his office.

Vic’s mind remained sharp. We were able to visit him until about a month before he passed away. He was worried about the world, but still eager to hear jokes, and to tell them.

He was a role model, and a pleasure to spend time with.  

Vic was a man of many parts, and his life was full of accomplishments, admirers, family and friends for whom his memory will be a blessing.

Sunday, September 17, 2023

Friday, November 24, 2023

Big Ideas: Auctions with Nobel Laureates Paul Milgrom and Robert Wilson

Ran Abramitzky interviews Bob Wilson and Paul Milgrom:

Thursday, November 23, 2023

Thanksgiving cranberries (brought to you by the Ocean Spray cranberry cooperative)

 The WSJ has the story:

These People Are Responsible for the Cranberry Sauce You Love to Hate  By Ben Cohen

"Ocean Spray['s...] farmers are responsible for 65% of the world’s cranberries. It’s not a publicly traded company. It’s not a traditional private company, either. It’s a cooperative founded nearly a century ago and owned by roughly 700 families. 


“The mindset and attitude that we need to come up with something is the spirit of what farmers do,” Hayes said. 

"It’s not exactly Apple, but that kind of innovation is baked into the world’s most valuable cranberry business. Ocean Spray wouldn’t have $2 billion in annual sales if it hadn’t adapted and produced new ideas at several critical junctures in the past century.


"The cooperative was started in 1930 by “three maverick farmers,” as Ocean Spray calls its founders. One of those entrepreneurs was Marcus Urann, a lawyer who purchased a bog in Massachusetts and went looking for ways to preserve cranberries and sell them year-round. His experiments led him to come up with something: He invented cranberry sauce in a can. The market for canned products soon became so large, and the competition in the cranberry industry so fierce, that Urann came up with something else, banding together with two farmers to establish Ocean Spray. 


"The model for Ocean Spray, Dairy Farmers of America and Land O’Lakes became popular because of a 1922 federal law that exempts cooperatives from antitrust regulations, allowing farmers to pool their resources for scale and collective power."

Wednesday, November 22, 2023

Political leadership in NYC: Mayor Eric Adams on antisemitism

Elected officials with executive responsibilities have difficult jobs. The Mayor of NYC has to make sure that garbage is collected, that potholes are filled, that corruption is contained.  But political leaders also have an opportunity and a responsibility to address broader social problems, and from a distance I can appreciate that NYC Mayor Eric Adams is speaking out against hate, and not flinching from naming antisemitism as he sees it surge back into public view,

Remarks by Mayor Eric Adams | Central Synagogue | November 17, 2023

Earlier (including the video of an earlier speech by Mayor Adams):

Tuesday, November 21, 2023

Balance of violence: prison-based criminal cartels, the case of Brazil's PCC.

The vexed relationship between banned markets and black markets is perhaps nowhere clearer than when prison based gangs of convicted drug dealers are able to extend their empires outside of prisons. While national authorities are able to capture, convict and imprison gang leaders, those gangs retain the ability to organize violence not only inside prisons but outside of them, and hence operate national and international black markets as well.

The Guardian has the story:

How a Brazilian prison gang became an international criminal leviathan  by Tom Phillips

"The PCC – First Capital Command – arose in the country’s notoriously brutal penitentiaries 30 years ago but now controls a billion-dollar drug trade supplying much of Europe’s cocaine,


"For much of its 30-year existence the PCC has been considered a jailhouse fraternity, which recruited incarcerated “brothers” such as the Venezuelan by offering them protection within Brazil’s violent, overcrowded prisons. Created in August 1993, it grew into Brazil’s most feared criminal faction, conquering drug markets, smuggling routes, shantytowns and prisons across Brazil, including in far-flung corners of the Amazon. It also became a major player in other South American countries such as neighbouring Paraguay where the group has been blamed for multimillion-dollar armed robberies and bombings and targeted assassinations.

But over the past five years, investigators say the PCC – which the US now calls one of the world’s most powerful organized crime groups – has morphed into an even more formidable force after forging lucrative alliances with partners ranging from Bolivian cocaine producers to Italian mafiosi. Today, the group boasts tens of thousands of members and has a growing portfolio of interests, including illegal goldmines in the Amazon. It controls one of South America’s most important trafficking routes – linking Bolivia and Brazil to Europe and Africa – and is partly responsible for a tsunami of cocaine that has brought car bombings, assassinations and gunfights to parts of Europe.


"During the 1990s, the PCC tightened its grip on São Paulo’s prison system but largely flew under the radar until thousands of guards and visitors were captured during a massive 2001 uprising. Five years later the group again made headlines, bringing São Paulo to a virtual standstill with a wave of coordinated attacks on police that caused hundreds of deaths.


"Having dominated much of Brazil’s domestic drug market – and established a monopoly over São Paulo’s crime scene – Gakiya said the PCC began looking overseas in late 2016. Deals were struck with Italy’s most powerful mafia group, the ’Ndrangheta, as well as Serbian and Albanian mafias, and the PCC began shipping tonnes of cocaine from Brazilian ports to Europe.


"Marcola, 55, who is serving a 342-year prison sentence for murder, robbery and drug trafficking, is also not a man to be crossed. In late 2018, Gakiya decided to transfer him to a high-security federal prison after the discovery of an audacious multimillion-dollar plot to free him with the help of foreign mercenaries, helicopters and anti-aircraft guns. “I knew it might change my life but I also realized it needed doing,” the prosecutor said, admitting he did not consult his family first.

Gakiya was no stranger to death threats, but moving Marcola turned his life upside down. PCC leaders issued a “decree” calling for the prosecutor’s assassination, condemning Gakiya to a reclusive existence he compared to the life of Giovanni Falcone, the anti-mafia crusader assassinated in 1992. “I hope, of course, not to share the same fate as Falcone,” added Gakiya..."

Monday, November 20, 2023

Global kidney exchange between Denmark and U.S.

 Here's a news story from North Carolina, home of one of the patient-donor pairs in the U.S.-Denmark kidney exchange, organized by the Alliance for Paired Kidney Donation (APKD).

Worldwide kidney transplant chain saves lives in Raleigh, Denmark, Colorado. by: Maggie Newland

"RALEIGH, N.C. (WNCN) — When a Raleigh musician needed a kidney, a friend of a friend offered to donate hers. The offer led to a kidney transplant chain stretching from the Triangle all the way to Denmark.


"Meanwhile, across the ocean, in Denmark, friends Peter Wichmann and Morton Berktoft were dealing with a similar issue. Wichmann wanted to donate his kidney to Berktoft, but they didn’t match either.

"Then something called a paired kidney exchange ended up helping all of them.  

"“It’s actually a Nobel prize-winning algorithm,” explained Krista Sweeney with AKPD. “They put these pairs into our system… We’re able to identify the best matches for each pair.”

"In this case, Kovacic donated her kidney to someone in Colorado. Their loved one donated a kidney to Berktoft, who flew to the U.S. for the surgery along with Wichmann, who donated a kidney to Adamo.


"Three months after the surgeries the donors and recipients are all doing well and got a chance to talk to each other in a virtual meeting.


“Even though the paired exchange wasn’t our initial plan it worked out so great for six people,” said Kovacic. “And three people’s lives to be saved.”


Earlier posts on Denmark-US exchange:

Monday, June 7, 2021

Sunday, November 19, 2023

Scott Kominers on the history of matching, at Tsinghua, tomorrow

 CMSA/Tsinghua Math-Science Literature Lecture: Scott Kominers

"Beginning in Spring 2020, the CMSA began hosting a lecture series on literature in the mathematical sciences, with a focus on significant developments in mathematics that have influenced the discipline, and the lifetime accomplishments of significant scholars."

Saturday, November 18, 2023

Will divorce become legal in the Philippines?

  The NYT has the story:

‘Just Like Medicine’: A New Push for Divorce in a Nation Where It’s Illegal.  A campaign in the Philippines that frames divorce as a basic human right is gaining momentum, despite systemic and religious barriers.  By Sui-Lee Wee

"Thousands of people like Ms. Nepomuceno are trapped in long-dead marriages in the Philippines, the only country in the world, other than the Vatican, where divorce remains illegal. 


"Partly because of their growing numbers and plight, attitudes in the country, where nearly 80 percent of the population is Catholic, have changed. Surveys show that half of Filipinos now support divorce. Even the president has signaled openness to the idea, and the Philippines is the closest it has ever been to legalizing divorce.

"But the issue is far from settled. The powerful Catholic Church has deemed pro-divorce activism to be “irrational advocacy.” Conservative lawmakers remain steadfast in their opposition.

"This has prompted some in the legalization camp to frame divorce as a basic human right, like access to health care or education.


"In recent months, a Senate committee approved a bill on divorce for the first time in more than 30 years. The bill is now awaiting a second reading in the Senate, which lawmakers say could happen next year.


"Divorce has a complicated history in the Philippines. During the Spanish colonial era, divorce was banned, but legal separation was allowed under narrow conditions. Under American occupation, it was made legal, but only on the grounds of adultery and concubinage. The Japanese, who occupied the Philippines during World War II, expanded the divorce law, allowing more grounds for people to seek divorce.

"That changed after the enactment of the country’s Civil Code in 1950. But Muslim citizens, who make up 5 percent of the population, are allowed to divorce, because in 1977, Ferdinand E. Marcos, the president at the time, signed legislation allowing it.


"A decade ago, when the Philippine Congress passed legislation that gave people access to contraception, the clergy held protests and threatened to excommunicate lawmakers for supporting the bill. This time, said Edcel Lagman, a congressman who has pushed for both issues, church officials have been less vocal in its opposition."

Friday, November 17, 2023

Report From a Multidisciplinary Symposium on the Future of Living Kidney Donor Transplantation

 How might we increase the number of lifesaving transplants from living kidney donors? Might we one day be able to reward donors? And what might we do until then, while we wait for something that will eventually replace human organ transplantation?  Here's the published account of last year's symposium.

Thomas G. Peters, John J. Fung, Janet Radcliffe-Richards, Sally Satel, Alvin E. Roth, Frank McCormick, Martha Gershun, Arthur J. Matas, John P. Roberts, Josh Morrison, Glenn M. Chertow, Laurie D. Lee, Philip J. Held, and Akinlolu Ojo, “Report From a Multidisciplinary Symposium on the Future of Living Kidney Donor Transplantation,” Progress in Transplantation  (forthcoming), Online first, Nov 15, 2023  (pdf here).

Abstract: Virtually all clinicians agree that living donor renal transplantation is the optimal treatment for permanent loss of kidney function. Yet, living donor kidney transplantation has not grown in the United States for more than 2 decades. A virtual symposium gathered experts to examine this shortcoming and to stimulate and clarify issues salient to improving living donation. The ethical principles of rewarding kidney donors and the limits of altruism as the exclusive compelling stimulus for donation were emphasized. Concepts that donor incentives could save up to 40 000 lives annually and considerable taxpayer dollars were examined, and survey data confirmed voter support for donor compensation. Objections to rewarding donors were also presented. Living donor kidney exchanges and limited numbers of deceased donor kidneys were reviewed. Discussants found consensus that attempts to increase living donation should include removing artificial barriers in donor evaluation, expansion of living donor chains, affirming the safety of live kidney donation, and assurance that donors incur no expense. If the current legal and practice standards persist, living kidney donation will fail to achieve its true potential to save lives.

Links to videos of the symposium presentations are here:

Thursday, November 16, 2023

Top trading cycles 'respect improvements' by rewarding agents whose endowments become more desirable

 Here's a wide-ranging paper that explores the way the Top Tradinig Cycles (TTC) algorithm 'respects improvements' by rewarding an agent whose endowment becomes more desirable.

Biró, Péter, Flip Klijn, Xenia Klimentova, and Ana Viana. "Shapley–Scarf Housing Markets: Respecting Improvement, Integer Programming, and Kidney Exchange." Mathematics of Operations Research (2023).

"Abstract: In a housing market of Shapley and Scarf, each agent is endowed with one indivisible object and has preferences over all objects. An allocation of the objects is in the (strong) core if there exists no (weakly) blocking coalition. We show that, for strict preferences, the unique strong core allocation “respects improvement”—if an agent’s object becomes more desirable for some other agents, then the agent’s allotment in the unique strong core allocation weakly improves. We extend this result to weak preferences for both the strong core (conditional on nonemptiness) and the set of competitive allocations (using probabilistic allocations and stochastic dominance). There are no counterparts of the latter two results in the two-sided matching literature. We provide examples to show how our results break down when there is a bound on the length of exchange cycles. Respecting improvements is an important property for applications of the housing markets model, such as kidney exchange: it incentivizes each patient to bring the best possible set of donors to the market. We conduct computer simulations using markets that resemble the pools of kidney exchange programs. We compare the game-theoretical solutions with current techniques (maximum size and maximum weight allocations) in terms of violations of the respecting improvement property. We find that game-theoretical solutions fare much better at respecting improvements even when exchange cycles are bounded, and they do so at a low efficiency cost. As a stepping stone for our simulations, we provide novel integer programming formulations for computing core, competitive, and strong core allocations."

Here is their literature review:

"The nonemptiness of the core is proved in Shapley and Scarf [47] by showing the balancedness of the corresponding nontransferable utility game and also in a constructive way by showing that David Gale’s famous top trading cycles (TTC) algorithm always yields competitive allocations. Roth and Postlewaite [40] later show that, for strict preferences, the TTC results in the unique strong core allocation, which coincides with the unique competitive allocation in this case. However, if preferences are not strict (i.e., ties are present), the strong core can be empty or contain more than one allocation, but the TTC still produces all competitive allocations. Wako [50] shows that the strong core is always a subset of the set of competitive allocations. Quint and Wako [39] provide an efficient algorithm for finding a strong core allocation whenever there exists one. Their work is further generalized and simplified by Cechlárová and Fleiner [19], who use graph models. Wako [52] shows that the set of competitive allocations coincides with the core based on an antisymmetric weak domination concept, which we refer to as Wako-core in this paper. This equivalence is key for our extension of the definition of competitive allocations to the case of bounded exchange cycles.

1.2.2. Respecting Improvement.

"For Gale and Shapley’s [23] college admissions model, Balinski and Sönmez [11] prove that SOSM respects improvement of student’s quality. Kominers [29] generalizes this result to more general settings. Balinski and Sönmez [11] also show that SOSM is the unique stable mechanism that respects improvement of student quality. Abdulkadiroğlu and Sönmez [3] propose and discuss the use of TTC in a model of school choice, which is closely related to the college admissions model. Abdulkadiroğlu and Che [2] state and Hatfield et al. [25] formally prove that the TTC mechanism respects improvement of student quality.

"Hatfield et al. [25] also focus on the other side of the market and study the existence of mechanisms that respect improvement of a college’s quality. The fact that colleges can match with multiple students leads to a strong impossibility result: they prove that there is no stable or Pareto-efficient mechanism that respects improvement of a college’s quality. In particular, the (Pareto-efficient) TTC mechanism does not respect improvement of a college’s quality.

"In the context of KEPs with pairwise exchanges, the incentives for bringing an additional donor to the exchange pool was first studied by Roth et al. [42]. In the model of housing markets their donor-monotonicity property boils down to the respecting improvement property. They show that so-called priority mechanisms are donor-monotonic if each agent’s preferences are dichotomous, that is, the agent is indifferent between all acceptable donors. However, if agents have nondichotomous preferences, then any mechanism that maximizes the number of pairwise exchanges (so, in particular, any priority mechanism) does not respect improvement. This can be easily seen by means of Example 4 in Section 3.3.


See also

The core of housing markets from an agent’s perspective: Is it worth sprucing up your home?  by Ildiko Schlotter, , Peter Biro, and Tamas Fleiner

Abstract. We study housing markets as introduced by Shapley and Scarf (1974). We investigate the computational complexity of various questions regarding the situation of an agent a in a housing market Hwe show that it is NP-hard to find an allocation in the core of H where (i) a receives a certain house, (ii) a does not receive a certain house, or (iii) a receives a house other than her own. We prove that the core of housing markets respects improvement in the following sense: given an allocation in the core of H where agent a receives a house h, if the value of the house owned by a increases, then the resulting housing market admits an allocation in its core in which a receives either h or a house that a prefers to h; moreover, such an allocation can be found efficiently. We further show an analogous result in the Stable Roommates setting by proving that stable matchings in a one-sided market also respect improvement.

Wednesday, November 15, 2023


 Here's the press release from the Einstein Foundation in Berlin:



The recipient of the Individual Award is Yves Moreau from the Katholieke Universiteit Leuven. Moreau ranks among the most ardent advocates for ethical standards in the utilization of human DNA data in the age of artificial intelligence and big data. He designs algorithms that protect personal privacy during the analysis of genetic data. This year’s Institutional Award recognizes the work of the Berkeley Initiative for Transparency in the Social Sciences (BITSS), which advocates for rigor, transparency, and reproducibility in social scientific research. The Institute achieves this through establishing open science practices, developing appropriate infrastructure, and conducting meta-research. The 2023 Early Career Award goes to the Responsible Research Assessment Initiative headed by Anne Gärtner (Dresden University of Technology). The project aims to identify, test, and establish novel criteria for the assessment of researchers and their output. Moving away from quantity of output and other unsuitable metrics, it will foreground quality of research by taking into account factors such as transparency, robustness, innovation, and cooperation. 


"Jury member Michel Cosnard, computer scientist at the Université Nice-Sophia-Antipolis, believes that Yves Moreau is highly deserving of the award, which recognizes his unwavering dedication on both professional and ethical fronts. “Moreau links deep research in DNA analysis and artificial intelligence with ethics, integrity, and human rights. His work and achievements serve as a cornerstone to help us confront the difficult social questions that arise from rapid technological developments.” 

"Fellow jury member and Stanford University economist Alvin Roth firmly endorses the chosen winner of the Institutional Award: “The Berkeley Initiative for Transparency in the Social Sciences plays an active, creative role in the ‘credibility revolution’ in science by promoting careful experimentation, and supporting efforts to make replication and verification commonplace.” 


The two previous awards

Monday, December 5, 2022

Tuesday, November 14, 2023

How have real estate agents kept commissions high? More on steering, by Barry, Fried, and Hatfield,

 Here's a paper that offers one channel for how residential real estate commissions have been maintained at a more or less constant percentage of house prices, while those prices have risen and while information about houses for sale has become more readily available.

Barry, Jordan and Fried, Will and Hatfield, John William, Et Tu, Agent? Commission-Based Steering in Residential Real Estate (October 9, 2023). Available at SSRN: or

Abstract: "Real estate agents are required to serve their clients’ best interests. However, policymakers have long suspected that buyer agents steer their clients away from properties that offer low buyer agent commissions. They are particularly concerned that steering is a key reason why agent commissions have remained high in the internet era, even as commissions in other industries have plummeted. Analyzing a new dataset, we provide the first systematic, nationwide evidence that buyer agents do in fact steer clients away from properties that offer low buyer agent commissions.

"Buyer agents play an important role in helping their clients find homes. We hypothesize that buyer agents may skip over low-commission homes in favor of high-commission homes when choosing which listings to forward to their clients. If so, low-commission listings would tend to garner fewer page views on public real estate portals like Zillow and Redfin. To test this theory, we track the number of page views that individual listings receive on Redfin. All else being equal, we find that low-commission listings receive fewer page views. This effect is most pronounced for listings with the lowest commissions, but even listings with commissions that are slightly below the going rate receive significantly fewer page views.

"We also find evidence that this steering has meaningful economic consequences. Homes with lower buyer agent commissions take longer to sell and are less likely to sell at all. Again, these effects are largest for the listings with the lowest commissions, which take 33% longer to sell nationwide. In a typical geographic market, our best estimate is that these lowest-commission properties face a 75% greater risk of not selling at all. Here too, even commissions that are slightly below the going rate are associated with longer sale times and higher risk of a failed sale.

"We explore the implications of our findings with respect to both the $52 trillion U.S. housing market and the ongoing scholarly debates regarding agency costs and Collaborative Industries."



Thursday, November 2, 2023

Monday, November 13, 2023

More on Realtor's contracts and practices, and the recent court decision

 Here are some further articles with some details about the recent court decision that real estate contracts are anticompetitive. Both are from the Washington Post:

Jury awards $1.8B in realty case that could shake up brokerage commissions. A Kansas City jury unanimously found that the National Association of Realtors and other organizations conspired to artificially inflate home sale commissions   By Julian Mark 

"The plaintiffs pointed to an NAR rule that required sellers to make a nonnegotiable commission offer before listing homes on the property database, the Multiple Listing Service, or MLS, which feeds widely used real estate sites including Zillow. That commission hovers around 5 to 6 percent of the sale price and is paid by the home seller to the sellers’ agent and the buyers’ agent. If sellers do not agree to the commission terms, they go virtually unseen in the market, Ketchmark said.

"The rule has stifled competition and has resulted in higher prices, the plaintiffs alleged. They argued that if the rule were not in place, buyers would pay commissions to their own agents while buyers’ agents would have to compete by offering lower rates. The lawsuit pointed to countries whose total real estate commissions average 1 to 3 percent, such as the United Kingdom, Singapore, the Netherlands, Australia and Belgium.


Real estate industry trembles over commissions on home sales. After jurors recently found that there was a scheme to inflate commissions, experts say changes could shake up the business  By Julian Mark

"The judge overseeing the case has the power to issue an injunction that could break up the century-old “bundled” or “cooperative” commissions system, in which sellers’ and buyers’ agents split a commission that typically ranges between 5 and 6 percent of the home sale price. 


"The cooperative compensation structure was established in 1913, when National Association of Real Estate Exchanges, the precursor to NAR, said its member agents should share commissions with agents that produced buyers, according to a 2015 study by economists Panle Jia Barwick and Maisy Wong. The commissions rate hit 5 percent in 1940 and has remained virtually unchanged ever since, according to the study.

"Commissions work differently in countries such as the United Kingdom, where sellers pay typically less than 2 percent, and buyers pay their own agents, according to the study."


And here's the cited paper:

Barwick, Panle Jia, Parag A. Pathak, and Maisy Wong. 2017. "Conflicts of Interest and Steering in Residential Brokerage." American Economic Journal: Applied Economics9 (3): 191-222.

Abstract: This paper documents uniformity in real estate commission rates offered to buyers' agents using 653,475 residential listings in eastern Massachusetts from 1998–2011. Properties listed with lower commission rates experience less favorable transaction outcomes: they are 5 percent less likely to sell and take 12 percent longer to sell. These adverse outcomes reflect decreased willingness of buyers' agents to intermediate low commission properties (steering), rather than heterogeneous seller preferences or reduced effort of listing agents. Offices with large market shares purchase a disproportionately small fraction of low commission properties. The negative outcomes for low commissions provide empirical support for regulatory concerns over steering.

Sunday, November 12, 2023

Misunderstandings: False Beliefs in Communication by Georg Weizsäcker

 Georg Weizsäcker  has a new book, just out from Open Book Publishers. You can read online or download it for free, or purchase a printed copy.

Misunderstandings: False Beliefs in Communication, by Georg Weizsäcker 

"What do we expect when we say something to someone, and what do they expect when they hear it? When is a conversation successful? The book considers a wide set of two-person conversations, and a bit of game theory, to show how conversational statements and their interpretations are governed by beliefs. Thinking about beliefs is suitable for communication analysis because beliefs are well-defined and measurable, allowing to differentiate between successful understandings and their less successful counterparts: misunderstandings.

"The book describes the theoretical framework and empirical measurements of misunderstandings – written by an economist, but in simple words and using interdisciplinary concepts. The material will benefit students and researchers of behavioural economics and its neighbouring fields, and anyone interested in human language."

Among the endorsements:

"The most Zen part of economics has to do with how people form beliefs about the beliefs of others. Georg Weizsäcker is a Zen master at explaining the origins of misunderstandings, particularly those arising from false beliefs about the beliefs of others.

Prof. Alvin E. Roth, Stanford University"

Saturday, November 11, 2023

Graduate hotels, and campus humor

 I've been spending some time at Berkeley this quarter, and have twice stayed at the Graduate Hotel adjacent to the campus, Graduate Berkeley.  The Graduate chain  of hotels has a business model in which they purchase an old hotel (in Berkeley it was the Durant), and update it in various ways. (As far as I can tell, every room has a poster from the movie The Graduate.)  They also feel free to take swipes at neighboring universities: a restroom off the lobby of the Berkeley hotel  includes some Stanford signage.

I notice that a Graduate hotel has recently opened in Palo Alto, near Stanford.  I'll have to stop there for a drink sometime.

Friday, November 10, 2023

Kidney Exchange: Within and Across Borders (video lecture).

 Below is a video of my 40 minute talk at Berkeley on Monday, on Kidney Exchange: Within and Across Borders, at the final workshop on Mathematics and Computer Science of Market and Mechanism Design,  at the Simons Laufer Mathematical Sciences Institute (SLMath). (But we warned or reassured, this isn't a mathematical lecture...)

Here's another link to the video if you have trouble connecting:

Thursday, November 9, 2023

Algorithms, Approximation, and Learning in Market and Mechanism Design at SLMath Berkeley this week--Thursday

 Thursday's program (last day)

 09:00 am 09:45 am
Stability and Learning in Strategic Games
Eva Tardos, Cornell University
 09:45 am 10:30 am
Statistical Contract Theory
Michael Jordan, University of California, Berkeley
 10:00 am 10:30 am
 11:00 am 11:45 am
Learning Bayes-Nash Equilibria in Auctions and Contests
Martin Bichler, Technical University of Munich
 11:30 am 11:45 am
 11:45 am 12:30 pm
Recent Advances in Computing Nash Equilibria in Markov Games
Ioannis Panageas, University of California, Irvine
 12:30 pm 02:30 pm
 02:30 pm 03:15 pm
Learning in Games and Markets: Talk 5
Tuomas Sandholm, Carnegie Mellon University
 03:15 pm 03:45 pm
Afternoon Tea
 03:45 pm 05:00 pm
Learning in Games and Markets: Closing Panel