It’s time to carefully but urgently rethink payments to kidney donors. My op-ed in the Washington Post

 This morning the Washington Post published my op-ed online (which is scheduled to appear in the print edition on Sunday). 800 words is hardly enough to explain why I think what I do...I could write a whole book about that.

But here's the op-ed: 

Why paying people to donate kidneys is a good idea

With 90,000 patients waiting for a kidney, compensating living donors would save lives.

May 8, 2026 at 6:30 a.m. EDT

 

By Alvin E. Roth

Alvin E. Roth is an economics professor at Stanford University and co-recipient, with Lloyd Shapley, of the 2012 Nobel Prize in economics. This article was adapted from his new book, "Moral Economics: From Prostitution to Organ Sales, What Controversial Transactions Reveal About How Markets Work."

It’s time to carefully but urgently rethink payments to kidney donors.

There are approximately 130,000 new cases of kidney failure annually in the United States. It is disproportionately a disease of the poor, and is four times as likely to affect Black people as White people. Kidney failure costs Medicare alone more than $55 billion per year, mostly for dialysis. More than 500,000 people are presently on dialysis, about half of whom will die within five years of beginning treatment. The best treatment for kidney failure is transplantation, but in 2025 fewer than 30,000 people in the United States received kidney transplants. So most people who could benefit from a lifesaving transplant will die without one.

 About 90,000 people are registered on the national waiting list to receive a deceased-donor kidney, and many more would be, if there were enough transplants for all who need them. Thousands die each year while waiting, and thousands more are removed from the waiting list when they become too sick to undergo transplant surgery.

The law in the U.S. and most of the world says kidneys must be gifts; their price must be zero. So, any attempt to raise the supply of kidneys by compensating donors would have to overcome the almost worldwide repugnance for payment.

About three-quarters of kidneys transplanted in the U.S. come from deceased donors, and the rest come from living donors: Healthy people have two kidneys and can remain healthy with one. But sometimes potential donors can’t donate to the person they love, because kidneys have to be medically compatible with the recipient. It’s a challenge even within families. For example, often a mother can’t receive a kidney from her spouse or children because during pregnancy, her immune system developed antibodies to some of their proteins.

 

 For the last quarter-century, living-donor transplants have also been arranged through kidney exchange, in which each patient receives a compatible kidney from another patient’s intended donor. Some of these transplants take place in long chains initiated by a nondirected donor, who donates a kidney, anonymously, to anyone who needs one. That begins a chain of donations in which each recipient’s intended donor passes the gift forward. Kidney exchange has made possible thousands of additional transplants, without payments to donors.  

Nevertheless, kidneys for transplant remain in tragically short supply. So it is past time to consider amending the 1984 law that prohibits giving “valuable consideration” for a kidney for transplant.

This would have to be done with care, because there are good reasons that the phrase “payments for kidneys” arouses repugnance. We wouldn’t want inappropriate donors to be unduly influenced to give up a kidney. (This is something already considered when screening the thousands of people who donate one of their kidneys each year without payment.) Another concern is that we wouldn’t want to live in a world in which only rich people could get kidneys, by buying them from poor people.

In the United States, we might think about letting individual states experiment with different regulations. Or we could explore a national system in which only the federal government could buy kidneys — from carefully qualified donors, after a significant period devoted to medical and psychological screening, and having obtained carefully informed consent. Those kidneys could then be allocated without regard to patients’ income, much as we presently allocate deceased-donor kidneys, which are treated as a national resource. 

 

It would be financially feasible to pay donors quite generously without requiring recipients to pay anything at all. Donors could be paid entirely from the savings to the health care system by taking patients off dialysis.

There is a long history of thoughtful arguments in favor of allowing kidney donors to be legally paid or compensated in some way, with carefully considered precautions. These include a current proposal called the End Kidney Deaths Act, which would establish a limited pilot program for a tax credit to nondirected kidney donors.

To be clear, we should keep trying for big long-term goals, such as vastly reducing the incidence of kidney disease by preventing or curing diabetes, hypertension and other causes. We should keep trying to expand deceased donation (perhaps by offering funeral benefits in gratitude to the next of kin who allow it). We should keep exploring cures that don’t require transplants of human organs. But we can save many lives now by being more generous to living donors, and it makes sense to start experimenting with ways to do this legally, ethically and equitably."

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And here's the picture they chose to accompany the op-ed.

 

 

 

 

 

 

 

Peter Rousseau comments on our field experiment involving the Econ job market, in PNAS

 My post yesterday was about the experiment about social media and the job market for economists.  I only noticed later that the PNAS also posted a comment on our article, by Professor Peter Rousseau, the secretary of the American Economic Association, who has a long and intimate familiarity with that job market, which the AEA has played a giant role in organizing.

 Improving the job market in economics (and beyond…) by Peter L. Rousseau  PNAS   May 4, 2026  https://doi.org/10.1073/pnas.2609971123

Here is the part of his comment directly connected to our paper:

" the authors make a welcome and useful contribution to the market design literature with a fascinating experiment designed to substitute for and even improve upon the informal information channels lost to the economics job market in the new postpandemic normal. Given that some job candidates are less active self-promoters than others and that, conversely, excessive self-promotion can in some cases be viewed as a negative by prospective recruiters, the authors’ proposed mechanism offers serious promise for leveling the playing field, even if just modestly, for economics job candidates in terms of their visibilities, and perhaps even for expanding the number of jobs actually filled over the course of a recruiting season.
 

"In the experiment, an AI-based algorithm, supplemented with some human checking and reassignments, matched selected economists on social media (i.e., the “influencers”) with willing job candidates based on the closeness of their research. About 43 percent of willing candidates were selected for this treatment. The key to the experiment lies in the matches themselves, which were assigned in a manner that did not take the relative prominence or institutional ranking of an influencer directly into account. All candidate participants were invited to post a tweet about their job market papers on a social media site created for this purpose, and the influencers were asked to post neutral quote-tweets about the members of the treatment group to which they had been assigned. If executed according to design, recruiters viewing the quote-tweets receive information about the closeness of a given candidate’s research interests to those of the influencer. This may function as a partial substitute for the painstaking process of deducing such information across the hundreds of application packets that recruiters receive with only a brief period for making initial decisions. Knowing that a candidate’s research is close to that of Professor “X” is a tangible signal that could make that candidate more likely to be interviewed or receive a campus flyout or job offer from an institution seeking an entry-level economist like Professor X. The experiment indicates that individuals in the treatment group did indeed receive more campus visits and job offers than candidates assigned to the control group, and that the effect on job offers was especially strong for women. It also finds, however, that these effects were more pronounced for candidates matched to influencers with relatively higher citation counts than for those matched to influencers with relatively more followers, as these two measures of prominence in the profession are not that highly correlated. 

" The question of scalability then becomes paramount. Considering the experiment’s positive findings, it is natural to assume that, if universally available, all job candidates would choose to participate and receive the treatment. The process would otherwise go on as stated with perhaps additional influencers being selected by the organizers to serve the larger pool of candidates. Two observations seem reasonable at this point: first, in such a setup, better information about matches could lead to more open positions being filled, which would be a better aggregate outcome; and second, the treatment might in practice benefit candidates from outside the very top departments the most. This is because candidates from the highest ranked departments, who are often perceived by recruiters as having a higher probability of eventually becoming a star, will typically receive more interviews, campus visits, and offers, but in the end can still only accept one offer. With an enlarged set of viable matches, this means that some candidates who may have been otherwise overlooked will find jobs. Of course, the job market may take longer to clear under this mechanism as candidates will have more options to consider before departments go to second or third rounds of offers.
 

"Casual observations of the job market among economics departments and their chairs do suggest that a number of recruiters are unable to fill positions they have posted. The AEA does not currently collect information on just how many, but the very existence of the “AEA Job Market Scramble,” where recruiters and unmatched candidates can post their availabilities on an online message board each March, is indicative of the challenge (3). The design of a job signaling mechanism by the AEA and its implementation in December of each year (4), where job candidates can list two departments to which they would like to express interest in an interview, is another such intervention aimed at easing the congestion.
Another interesting result is that women appear to benefit most from the treatment, while this benefit does not extend to members of other groups traditionally underrepresented in economics. The authors point to existing evidence indicating that women on average tend to be less active promoters of their own research on social media than others and suggest that the additional visibility provided by the quote-tweets could be leading to more job offers. This potential channel, of course, could also be viable for any candidate with a tendency to self-promote less. To explain a special advantage for women, one could note the possibility of forces in the 2022–2023 job market where departments seeking to improve the gender balances of their faculties became aware of candidates through the mechanism who they may have otherwise overlooked. If this is the case, the next question to ask is why does the effect not carry over for members of other underrepresented groups? The answer, though no doubt a speculative one, may lie in the preexistence of other mechanisms and informal channels for promoting such candidates, rendering the marginal effects of the authors’ particular intervention not statistically significant.
Finally, while having the potential to increase the number of matches and raise their average quality, the effects of the authors’ intervention will be subject to some randomness based on the assignment of a given candidate’s influencer. For example, when any influencer posts a quote-tweet about a candidate who has been independently and objectively determined to have close research interests, that candidate’s post tends to receive more views and likes on X than those in the control group, and the extent of this visibility correlates with the size of the influencer’s following. Yet these effects do not seem to transfer downstream to job outcomes, where candidates receiving quote-tweets from highly cited influencers are the ones tending to see more offers. In a real sense, the adage “all publicity is good publicity,” often applied to economics research, may not be always true. The assignment of influencers to candidates, even if randomized, will matter for individual outcomes even though the aggregate effects of the intervention are positive. Given the potential individual benefits compared to nontreatment, however, job candidates would likely embrace the residual uncertainty and participate in the mechanism.
 

"The intervention designed by Qiu et al. may hold even greater promise outside of the economics discipline. In the natural sciences, for example, recruiting for scarce academic postdoctoral positions among new PhDs at a similar career stage, which are markets typically saturated with candidates, often moves directly to a very limited allocation of campus visits based in no small part on letters and other communications from mentors, some of whom could be less than ideally matched with their students or less well known than would-be assigned influencers. These cases are ones in which an enhanced visibility of candidates, when coupled with independent information about the closeness of their work to what senior researchers and their groups might be seeking, could lead to the greater advancement of science more generally.
 : 
"Competing interests P.L.R. has served since 2012 as Secretary-Treasurer of the American Economic Association, a 501(c)(3) non-profit deeply committed to improving the job market for new Ph.D. economists, and for which one of the companion article’s co-authors (A. E. Roth) served as President in 2017.

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 Peter's comment and our paper appeared online, but won't appear in print until next week in the May 12, 2026 | vol. 123 | no. 19 issue of PNAS.

 

Yesterday's post: 

Tuesday, May 5, 2026  Social media, job market outcomes, and ethics of field experiments, by Qiu, Chen, Cohn and Roth in PNAS

 

Australia has more unpaid beekeepers than blood donors

 If only there were some way for Australia to become self-sufficient in blood plasma, so it could stop having to buy it from the US...

The Financial Times has the story:

Australia’s drive to get more blood flowing
The country has more recreational beekeepers than regular donors and is forced to rely on imports  by Nic Fildes 

" Australia needs 100,000 new donors every year to meet its need for blood and plasma. But there are more recreational beekeepers in Australia than people who have actively donated their blood three times or more.

"This is not only an Australian challenge. Most countries have a supply gap. One problem is that the legion of older donors that has kept donations flowing for decades is dwindling and younger generations are not donating or do not return after they’ve tried it once. 

...

"The situation is particularly acute for plasma — the yellow-coloured component of blood sometimes called liquid gold — which is a vital ingredient for 18 different life-saving procedures ranging from immune deficiency treatment to heart surgery. 

Australia supplies only 38 per cent of its own plasma and spends about A$600mn a year to import it — more than double what was spent a decade ago. A report published by the state of New South Wales suggests imports needed could rise to 66 per cent of the total by 2030, meaning taxpayers are set to foot an even larger plasma bill.

For now, Australia relies on the US, where people earn up to $70 per donation, which supplies about 70 per cent of the world’s plasma."

 

Could A.I. be good for scientists but bad for science?

 There has been recent attention to using LLMs to generate novel (and often correct) mathematical proofs, prompted by plain English prompts.

A recent Amazon blog post by Michael Kearns and Aaron Roth recounts how they have been able to collaborate with a LLM in the production of increasingly sophisticated proofs of new results. They anticipate that this is a development that will only continue to grow in usefulness. At the same time, they worry about what impact it may have both on the training of new mathematical scientists, and on the peer review process (as the cost of writing polished and correct papers falls faster than the cost of evaluating them for importance). Perhaps unsurprisingly, one of the first fields to feel the strain of this imbalance has been theoretical  research into machine learning models.

How AI is changing the nature of mathematical research  
What machine learning theorists learned using AI agents to generate proofs — and what comes next.

By Michael Kearns and Aaron Roth

“Specifically, how can intuition and “good taste” in scientific research be developed when AI automates many of the steps that have historically been used to train young researchers? Peer review is another challenge: AI-generated research papers, quickly churned out at scale, highlight the limitations of peer review and modern-day publishing structures and also exacerbate already emerging challenges to incentives for scientific success. Without claiming to have answers or solutions to these concerns, we are personally living through them and will discuss each in turn.
…
“Historically, people earn expertise in the mathematical sciences through struggle as junior researchers. PhD students spend years working through the details of technical arguments to gain hard-won intuitions about when a proof approach is promising, when they are being led astray by a problem, or what constitutes a novel and interesting research direction.

“But these aspects of being a researcher are exactly what AI tools are “giving away”. If doctoral students can simply ask AI for proofs — which is extremely tempting, especially when it is in service of advancing research — how do they develop the experience and skill that, for now at least, are required to use AI tools productively in the first place?
…
“Breaking and remaking peer review
“From our perspective, peer review is not only, or even primarily, a process to verify the correctness and quality of research. Rather, its purpose is to focus a scarce resource — the attention of the research community — in the right places. Science progresses as researchers build on each other’s work, but there is already too much work out there for anyone to keep up with. The publication process should help identify the most interesting and promising directions, so they can be more efficiently and thoroughly developed.
…
“AI tools make it much easier to produce work that looks polished and correct, dramatically lowering the barrier to generating “papers” that can be submitted to journals and conferences. Many of these papers are neither interesting nor actually correct — but discovering this requires significant effort from reviewers.

This is straining an already overburdened machine learning publishing ecosystem struggling with tens of thousands of submissions per venue. We have seen that reducing the time and effort needed to produce "a paper" — not necessarily a good paper — is beginning to destabilize our existing institutions for peer review. The most recent iterations of AI and ML conferences have seen the number of submissions growing by large multiples, with a significant number of papers polished by AI, but ultimately of low quality, making it surprisingly far through the review process before being noticed and called out.
“This is a problem across research fields, partially because it’s creating a market for AI-generated papers. This has in turn engendered a countermarket for AI-assisted detection of AI-generated papers — much like the familiar technological arms races around things like spam and its detection, but with the integrity of scientific publication at stake, not just the filtration of annoying or fraudulent e-mails.

…
“Without a serious, community-wide re-evaluation of peer review, AI threatens to arrest scientific progress at the community level even as it accelerates it at the level of individual researchers.” 

Kidney exchange comes to Hungary

Péter Biró  writes with good news about kidney exchange in Hungary.

 Here's the announcement from the  University of Pécs, of the first kidney exchange performed in Hungary, following the first legislation passed to legalize kidney exchange in 2014. (And more details follow from a second announcement below.)

The first cross-donation kidney transplant was performed in Hungary at the University of Pécs Clinical Center  2026.01.29

"The first cross-donation kidney transplant performed in Hungary a few days ago can be considered a new milestone in the history of organ transplantation in Hungary. Within the framework of the living donor kidney exchange program, two women received new kidneys at the Department of Surgery of the University of Pécs Clinical Center (PTE KK), which gives them the opportunity for a better quality of life. It is particularly interesting that in both cases the organ donor was a male member of the other couple.

...

"In his speech, Dr. Péter Szakály, Head of Department of the Department of Surgery of the University of Pécs, emphasized that: The establishment of a national pool was of fundamental importance in this program, and this program will be able to operate successfully in the future as well if there are as many such couples as possible. He also added that compared to traditional kidney transplantation, living donor transplantation is always a much greater challenge (...) Transplantation with a living donor comes with increased responsibility, as it involves a healthy donor. In this case, two surgeries were performed at the same time: Ádám Varga, assistant professor, and I simultaneously removed and replaced the organs between the two pairs from the adjacent operating room. 

"Since 2014, the law allows this type of transplant, but no specific surgeries have been performed so far. Recognizing this shortcoming, at the initiative of the National Hospital Administration, the four kidney transplant centers in Hungary and the Regional Kidney Transplant Committees operating there, in cooperation with the National Blood Transfusion Service, have developed a nationally uniform program in accordance with the legislation in force, which ensures equal opportunities for all patients who voluntarily enter the program. This became the living donor kidney transplant exchange program, which was launched in Hungary on June 21, 2024. The search for optimally compatible pairings between the pairs applying for the program is carried out with the help of a software developed for this purpose." 

#########

And here is the emailed announcement forwarded by Peter Biro, who has been a champion of kidney exchange in Europe for many years now:

Dear EURO-KEP Colleagues,

 

We are pleased to inform you that we have reached a significant milestone within the Hungarian Kidney Paired Kidney Exchange Program (HKEP), in line with the objectives of the EURO-KEP initiative.

 

On January 20, 2026, the first two kidney transplants were successfully performed in Hungary within the national living donor kidney exchange program. The surgeries took place at the University of Pécs Clinical Centre, marking the first realization of kidney cross-over donation in the country.

We believe that this milestone, supported by a well-structured professional and patient information campaign lasting more than a year and a half, will contribute to increasing the number of living donor kidney transplants and encourage more patients and voluntary donors to join kidney exchange programs. This, in turn, will support further kidney exchanges and improve equal access to transplantation.

 

Chronology and key developments of the Hungarian KEP

• June 2024 – With the support and authorization of the National Directorate General for Hospitals (OKFŐ), a nationally unified kidney paired exchange program was launched, coordinated by the National Blood Transfusion Service, with the participation of all four Hungarian kidney transplant centers and regional waiting list committees.
• Since the launch – The matching algorithm has been run every three months; to date, six matching runs have been completed, involving 57 donors and 44 recipients. The seventh run is scheduled for tomorrow.
• July 2025 – A key legislative amendment entered into force, allowing:
• simultaneous transplants among more than two donor–recipient pairs in a closed chain,
• transplant surgeries to be performed in different centers, enabling patients to remain at their original listing centers and
• not only incompatible pairs can join the program, but compatible pairs in the hope of better matching.
• Following the legal amendment, an updated and detailed printed patient information package was distributed nationwide, with the involvement of all dialysis units and transplant centers.
• During the optimization process, a clinically acceptable match was identified between two married couples. In both cases, the male partner donated a kidney to the female recipient of the other couple. The transplant surgeries were performed on 20 January 2026 at the Surgical Clinic of the University of Pécs Clinical Centre. In both cases, graft function started immediately. The recipients and donors are in good condition and both patients were discharged home on Friday.

We consider this achievement a significant milestone in Hungarian transplantation and a meaningful contribution to the shared European objectives of the EURO-KEP project. We remain committed to continuing this work in the service of saving lives.

 

Best regards,

 

Dr. Sándor Mihály, Ph.D  
Director of transplantation

Honorary College Associate Professor at Semmelweis University

General Secretary of the Hungarian Transplant Society

EDTCO Past-Chair 2023-2025

 

 

Organ Coordination Office

Central Waiting List Office

National Organ and Tissue Donation Opting-out Registry

Hungarian Stem Cell Donor Registry

 

The market for used underwear, in the journal Genre, sexualité & société

 The study of repugnant transactions and controversial markets can lead to some strange markets.

 In the latest issue of the journal Genre, sexualité & société (after right clicking to translate to English) :

Product qualification in a contested market: The case of the used underwear market
by Ludine Cayla and Julien Gradoz
https://doi-org.stanford.idm.oclc.org/10.4000/154ww 

Abstract: This article focuses on the used underwear market, defined as the market for underwear that has been worn by one or more individuals and sold unwashed, meaning it contains deliberately left secretions and fluids. It distinguishes websites where the nature of the product sold must be concealed (such as resale websites for secondhand items) due to the prohibition of the transactions, and websites where the product can be openly discussed (such as websites specializing in the sale of sexual items). This distinction allows for the study of the issue of product qualification and disqualification in a contested market, which has been hardly explored. More broadly, this article helps identify the main characteristics of an overlooked market that, until now, has only been the subject of sensationalist analyses. 

"this is a "contested market," that is, a market in which some people would like to carry out transactions, but third parties oppose them on the basis of moral considerations. This opposition can then translate into constraints placed on the organization of the market (Roth, 2007), such as its prohibition (e.g., organs), the prohibition of advertising (cigarettes), difficulties in obtaining a bank loan (pornography), the imposition of punitive taxes (sodas), or even the stigmatization of participants in the transactions. Contested markets have been the subject of a substantial body of literature over the past decade (e.g., Steiner and Trespeuch, 2014; Bertrand et al ., 2020; Bertrand and Panitch, 2024; Gradoz and Dekker, 2025), and this article proposes to analyze the used underwear market based on this literature, moving beyond the sensationalism that has prevailed until now. This literature has focused in particular on the justifications used by third parties to challenge the existence of certain markets, or on the strategies implemented by participants in transactions to cope with the constraints resulting from this challenge." 

Why I Chose to Get E. Coli. — by Josh Morrison

 Josh Morrison is a glutton for (effective) altruism: he's a nondirected kidney donor (who founded the advocacy organization WaitlistZero), and he's an advocate of human challenge trials for vaccines, who founded the organization OneDaySooner.  He reports his own recent experiences as a challenge trial participant, in MedPage Today:

Why I Chose to Get E. Coli. — Human challenge trials can accelerate medical innovation  by Josh Morrison

" challenge trials have been essential for scientific advancements that may not have been possible (or would have taken much longer) with traditional studies. Challenge studies were crucial to developing malaria vaccines. The correlates of protection they established for influenza immunology are still used to license flu vaccines today, and they played an important role in discovering the origins of both ulcers and yellow fever.

"The E. coli vaccine study I joined was at the University of Maryland School of Medicine's Center for Vaccine Development (CVD). Two of my friends had been in studies at the CVD and had positive experiences overall. I felt like the E.coli vaccine in particular was an important one, so I decided it was time for me to participate too.

"To start, half the participants received the first vaccine in the series and half got a placebo. These initial shots and their associated follow-up were part of eight appointments over 3 months. At our appointments, we had our vitals checked and, in some cases, we had our blood collected or received another vaccine. At appointments the week after a vaccination, we'd provide a stool sample. The study culminated in a 9-day quarantine in Baltimore where were we were exposed to the infectious agent: It was time to drink the E. coli.

"The E. coli was suspended in a bicarbonate solution and tasted like Gatorade without the sugar or flavoring. I remember chuckling nervously as I drank it alongside my fellow participants. It was such an odd experience; I felt like an astronaut counting down for liftoff. 

...

"People's motivations for being in the study included the money (about $4,500). But most of my fellow participants were also excited about the chance to be part of important research and were motivated by the novelty of the experience.

...

"

This was the first challenge study I've participated in, despite having been connected to the field for 5 years. I run 1Day Sooner, a nonprofit that advocates on behalf of challenge study volunteers. Some of my colleagues have been challenged in Shigella, Zika, Malaria, COVID, and Salmonella studies. But I never have because I live in New York and I'm not aware of any institutions in New York that run challenge studies. That may sound surprising, but there are only about 30 challenge studies globally each year, and the U.S. is a relative laggard compared to Europe.

"You might be wondering, would I participate in another one? I would, though I'd prefer something outpatient that didn't require a strict quarantine."