Two photos remind me of the day to day market design activity at Stanford.
Tinglong Dai joined our Wednesday market design coffee and sent along this picture. (You can see who came by plane and who came by bike...) He wrote about his visit here.
And Matias Cersosimo successfully defended his dissertation on Friday, which included market design experiments like this one.
Here's a paper by several Dutch computer scientists, which seems to be motivated by the problem of international kidney exchange within the EU, in which there are lots of concerns about fairness between countries. But (as the paper notes) these could also apply to individual transplant centers, in the U.S. context. The thrust of the paper is that looking for exchanges that won't be rejected ex post in a full information environment may be more productive than looking for ways to incentivize countries or transplant centers to reveal their full sets of patient donor pairs in an incomplete information environment.
Blom, Danny, Bart Smeulders, and Frits Spieksma. "Rejection-Proof Mechanisms for Multi-Agent Kidney Exchange." Games and Economic Behavior (2023).
Abstract: Kidney exchange programs (KEPs) increase kidney transplantation by facilitating the exchange of incompatible donors. Increasing the scale of KEPs leads to more opportunities for transplants. Collaboration between transplant organizations (agents) is thus desirable. As agents are primarily interested in providing transplants for their own patients, collaboration requires balancing individual and common objectives. In this paper, we consider ex-post strategic behavior, where agents can modify a proposed set of kidney exchanges. We introduce the class of rejection-proof mechanisms, which propose a set of exchanges such that agents have no incentive to reject them. We provide an exact mechanism and establish that the underlying optimization problem is
we also describe computationally less demanding heuristic mechanisms. We show rejection-proofness can be achieved at a limited cost for typical instances. Furthermore, our experiments show that the proposed rejection-proof mechanisms also remove incentives for strategic behavior in the ex-ante setting, where agents withhold information.
The University of Bern's Hans Sigrist Prize has been awarded to Penn computer scientist Aaron Roth, and will be celebrated today.
Here's an interview:
Aaron Roth: Pioneer of fair algorithms In December 2023, the most highly endowed prize of the University of Bern will go to the US computer scientist Aaron Roth. His research aims to incorporate social norms into algorithms and to better protect privacy. by Ivo Schmucki
"There are researchers who sit down and take on long-standing problems and just solve them, but I am not smart enough to do that," says Aaron Roth. "So, I have to be the other kind of researcher. I try to define a new problem that no one has worked on yet but that might be interesting."
"Aaron Roth's own modesty may stand in the way of understanding the depth of his contributions. In fact, when he authored his doctoral thesis on differential privacy about 15 years ago and then wrote on the fairness of algorithms a few years later, terms like “Artificial Intelligence” and “Machine Learning” were far from being as firmly anchored in our everyday lives as they are today. Aaron Roth was thus a pioneer, laying the foundation for a new branch of research.
"I am interested in real problems. Issues like data protection are becoming increasingly important as more and more data is generated and collected about all of us," says Aaron Roth about his research during the Hans Sigrist Foundation’s traditional interview with the prize winner. He focuses on algorithmic fairness, differential privacy, and their applications in machine learning and data analysis.
...
"It is important that more attention is paid to these topics," says Mathematics Professor Christiane Tretter, chair of this year's Hans Sigrist Prize Committee. Tretter says that many people perceive fairness and algorithms as two completely different poles, situated in different disciplines and incompatible with each other. "It is fascinating that Aaron Roth’s work shows that this is not a contradiction."
...
"The first step to improving the analysis of large data sets is to be aware of the problem: "We need to realize that data analysis can be problematic. Once we agree on this, we can consider how we can solve the problems," says Aaron Roth."
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."
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Earlier:
"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.
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
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.
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."
Yesterday, at Etz Chayim Synagogue, Palo Alto.
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."
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..."
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:
CMSA/Tsinghua Math-Science Literature Lecture: Scott Kominers
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."
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 https://journals.sagepub.com/doi/full/10.1177/15269248231212911 (pdf here).
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 H: we 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.
Here's the press release from the Einstein Foundation in Berlin:
THE WINNERS OF THE 2023 EINSTEIN FOUNDATION AWARD FOR PROMOTING QUALITY IN RESEARCH
"THE EINSTEIN FOUNDATION BERLIN IS TO HONOR BELGIAN BIOINFORMATICIAN YVES MOREAU, THE BERKELEY INITIATIVE FOR TRANSPARENCY IN THE SOCIAL SCIENCES, AND THE RESPONSIBLE RESEARCH ASSESSMENT INITIATIVE WITH THIS YEAR’S EINSTEIN FOUNDATION AWARD FOR PROMOTING QUALITY IN RESEARCH 2023.
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.”
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The two previous awards
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: https://ssrn.com/abstract=4596391 or http://dx.doi.org/10.2139/ssrn.4596391
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."
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