KENNETH ARROW’S LAST THEOREM by Paul Milgrom

 Here's a fitting tribute to Ken Arrow, who died in 2017, in the special issue of the Journal of Mechanism and Institution Design in Hono(u)r of (the still very much alive) Vince Crawford, edited by Alex Tetylboym

KENNETH ARROW’S LAST THEOREM  by Paul Milgrom, in The Journal of Mechanism and Institution Design 9, no. 1 (2024): 7-11.

ABSTRACT: In Kenneth Arrow’s last week of life at age 95, he reported that “I began my research career with an impossibility theorem. If I had time now, my last theorem would be an impossibility theorem about social choice for environmental policy.” This paper completes the formalization, proof, and discussion of the theorem that Arrow then described. 

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Some earlier tributes to Ken:

Tuesday, February 21, 2017

Ken Arrow (1921-2017)

Saturday, September 23, 2017

Tributes to Ken Arrow

Monday, October 9, 2017

Celebration of Ken Arrow at Stanford

Friday, October 13, 2017

Pictures from the celebration of Ken Arrow

 

 

 

 

Cheating on exams in India , and exam design suggestions from Spain

 India, where government jobs are allocated based on scores on a variety of national exams, cheating is a big business. One form it takes is sale of upcoming exam questions. 

An experiment conducted in Spain by Klijn, Alaoui, and Vorsatz, which introduced multiple versions of an online exam, suggests that this may reduce cheating by people who take the exam after others have already taken it.

 From the NYT:

These Exams Mean Everything in India. Thieves See a Gold Mine.
In a country where government jobs are highly coveted, the tests that govern hiring are a lucrative target for criminal gangs. By Mujib Mashal and Hari Kumar

 "Allotting jobs on the basis of exam results conveys a sense of fairness. But with competition so fierce, the temptation to seek shortcuts can be strong.

"Some aspirants, while spending long hours in study groups, also keep an eye out for shadowy figures offering access to exams.

 

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From the Indian Express

Bill in Lok Sabha to check paper leaks, use of unfair means in govt recruitment exams
At present, there is no specific substantive law to deal with unfair means adopted or offences committed by various entities involved in the conduct of public examinations by the central government and its agencies. 

"The Public Examinations (Prevention of Unfair Means) Bill, 2024, introduced by Union Minister of State for Personnel Jitendra Singh, mentions “leakage of question paper or answer key”, “directly or indirectly assisting the candidate in any manner unauthorisedly in the public examination” and “tampering with the computer network or a computer resource or a computer system” as offences done by a person, group of persons or institutions."

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 And here's an experiment with exam design, involving a Spanish exam:

Online Academic Exams: Does Multiplicity of Exam Versions Mitigate Cheating?  by Flip Klijn,  Mehdi Mdaghri Alaoui, and Marc Vorsatz

Abstract: We study academic integrity in a final exam of a game theory course with 463 undergraduate students at a major Spanish university. The exam is an unproctored online multiple-choice exam without backtracking. A key characteristic is that for each (type of) problem, groups of students receive different versions. Moreover, each problem version is assigned to one subgroup during one stage of the exam and to another subgroup during an immediately consecutive later stage. Thus, we can exploit grade points and timestamps to study students’ academic integrity. We observe a significant decrease in completion time at each later stage; however, surprisingly, there is no corresponding impact on average grade points. The precise number of different versions does not seem to have an effect on either variable. Our findings thus suggest that employing a limited number of distinct problem versions (as few as two) can diminish cheating effectiveness in online exams."

If I don't do it someone else will: markets and morals

 Here's a paper reporting an experiment that suggests that people are more willing to ignore the negative externalities they impose on others in a market in which they have little effect on quantities consumed. (They interpret this as being a moral question, hence the title.)

Ziegler, Andreas GB, Giorgia Romagnoli, and Theo Offerman. "Morals in multi-unit markets." Journal of the European Economic Association, Volume 22, Issue 5, October 2024, Pages 2225–2260, https://doi.org/10.1093/jeea/jvae001

"Abstract: We examine how the erosion of morals, norms, and norm compliance in markets depends on the market power of individual traders. Previously studied markets allow traders to exchange at most one unit and provide market power to individual traders by de-activating two forces: (i) the replacement logic, whereby immoral trading is justified by the belief that others would trade otherwise and (ii) market selection, by which the least moral trader determines aggregate quantities. In an experiment, we compare single-unit to (more common) multi-unit markets, which may activate these forces. Multi-unit markets, in contrast to single-unit markets, lead to a complete erosion of morals. This is associated primarily with a deterioration in norm compliance: the observed level of immoral trade is in contrast with the prevailing social norm. The replacement logic is the main mechanism driving this finding.

HT: Stephanie Wang

Income inequality, risk, and repugnance by Hauge, Kverndokk, and Lange

Two recent papers by  Karen Hauge, Snorre Kverndokk, and Andreas Lange report on the roles played by inequality and risk in causing repugnance to markets.

First, an experiment, motivated by a hypothetical market in kidneys (expressed in abstract terms), that finds that income inequality boosts repugnance to trade.

Hauge, Karen E., Snorre Kverndokk, and Andreas Lange. "Opposition to markets: Experimental evidence." Journal of Economic Behavior & Organization 227 (2024): 106743.

Abstract: We experimentally investigate reasons for opposing market institutions. The experiment shows that opposition to implementing market institutions varies by background characteristics and shows that distributional concerns are a reason for opposing trade institutions. We find no evidence that the opposition to trade is due to risk preferences or paternalistic motives. A main driver of the opposition to trade is the information about background conditions: veils of uncertainty increase the support for the trade institution.

"This paper reports experimental evidence to better understand potential opposition to market institutions, i.e. for allowing people to trade. For this, we abstract from repugnancy concerns that relate to the specific characteristics of the good or service in question, and rather reduces the setting to the payoff dimension and thus the involved risks and distributional concerns. While we use a neutral framing, organ trade, in particular, trade in kidneys, inspires the set-up of the experiment. Trading kidneys for payment is illegal worldwide, apart from in Iran.1 While it is obvious that persons with kidney issues would substantially benefit from a transplant, healthy donors expose themselves to risk (e.g., Lentine and Patel 2012). Currently, there is not a large income gap between donors and recipients in the US (Gill et al., 2012). Nevertheless, studies suggest that - at a given price - the poor would have larger incentives to donate and therefore, are more exposed to potential risks (Moniruzzaman, 2012; Parada-Contzen and Vásquez-Lavín, 2019) and thus potentially more vulnerable in terms of Satz (2010).2 To illustrate this in the experiment, we vary both the initial income of players (rich/poor) as well as their condition (healthy/sick) which combined affect their potential prospects with and without trade. 

...

"In our experiment, a share of 20 % of respondents across all treatments oppose the trade institution although it is constructed such that personal expected payoff is unaffected or improved. We find that the major reasons individuals vote against trade are the unfair distributions of gains from trade. Importantly, the opposition towards trade is partly self-serving: opposition is lower among those that benefit the most from implementing a market institution. Specifically, we find a significantly smaller opposition to trade institutions when participants are behind the veil of ignorance and do not know their income level, their (abstractly defined) health condition, and thus, how trade affects their payoff. Similarly, we find that distributing gains from trade more evenly, thus benefiting the poor to a larger extent, reduces opposition to trade among the poor."

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And here's a related survey study:

Hauge, Karen Evelyn, Snorre Kverndokk, and Andreas Lange. "On the opposition to market institutions on moral grounds." Humanities and Social Sciences Communications 11, no. 1 (2024): 1-8.

Abstract

"From a liberal viewpoint, voluntary trade appears to be something that should meet universal approval. If no one is obliged to trade, establishing a market institution could only make all better off. Nonetheless, specific market institutions meet substantial skepticism and criticism. This paper extends the extant literature by surveying the moral opposition towards trade in multiple dimensions and linking this to policy support measures. We provide survey results on moral opposition to trade in organs, sex services, surrogate mothers, trade in carbon permits, goods produced in poor countries, and food from countries where people suffer from hunger. These cover the potential reasons for opposing trade institutions: moral concerns, paternalism regarding risk-taking, and distributional concerns. Beyond this, we measure support for policies on unemployment benefits, risk prevention, equality goals within society, and redistribution. The survey of Amazon Mechanical Turk workers from the U.S. reveals significant moral opposition to trade in diverse dimensions. About a third of the participants strongly oppose trade in body items, sex services, and food imports from countries where a large proportion of the population suffers from hunger and malnutrition. Fewer participants strongly oppose trading CO2 permits, importing from developing countries, or allowing surrogate mothership. Besides other correlates (e.g., gender, education, being conservative), individuals’ attitudes towards imposing risks on others are identified as an important correlate of the opposition to trade for all the contexts of trade: those who are averse to exposing others to risk for their own advantage are more likely to oppose trading institutions. This measure of social preferences also relates to support for policies on risk prevention, equality goals within society, and redistribution. We discuss potential mechanisms behind this explanatory power of the newly identified measure."

Practical market design makes policy recommendations (which can violate NBER publication policy)

The National Bureau of Economic Research (NBER) publishes a widely read series of working papers, before publication in refereed journals. They also distribute a list of papers that have been published in medical journals, since those journals don't allow prepublication in working papers.  For both these series the NBER has a rule against papers that make policy recommendations.

This is sometimes a problem for the field of market design, since practical market design is about finding ways to improve the operation of markets, which is a kind of policy advice. I encountered this recently with the two papers described below, published in medical journals, which apparently are too policy related: the policy being to save more lives by arranging more transplants, in this case of hearts and kidneys respectively. (Medical journals have their own conventions, but aren't opposed to advice on medical practice...)

I received the following email from the NBER, accompanied by a line of explanation for each paper.

The email began:

"I apologize for my belated response about your journal articles; while the subject matter is clearly vital, after review of the full-text, we determined that your articles make policy recommendations that are too specific for NBER’s policy on working papers (which we apply to papers in the article list)."

 It then continued by highlighting the offending sentences in each article:

1. Alyssa Power MD*, Kurt R. Sweat MA*, Alvin Roth PhD, John C. Dykes MD, Beth Kaufman MD, Michael Ma MD, Sharon Chen MD, MPH, Seth A. Hollander MD, Elizabeth Profita MD, David N Rosenthal MD, Lynsey Barkoff NP, Chiu-Yu Chen MD PhD, Ryan R. Davies MD, Christopher S. Almond MD, MPH, “Contemporary Pediatric Heart Transplant Waitlist Mortality,” Journal of the American College of Cardiology, Vol 84, no. 7, August 13, 2024: 620-632.https://www.sciencedirect.com/science/article/pii/S0735109724075624

"Policy language:  A more flexible allocation system that accurately reflects patient-specific risks and considers transplant benefit is urgently needed."

2. Vivek B. Kute, Himanshu V Patel, Subho Banerjee,Divyesh P Engineer, Ruchir B Dave, Nauka Shah, Sanshriti Chauhan ,Harishankar Meshram , Priyash Tambi  , Akash Shah, Khushboo Saxena,Manish Balwani , Vishal Parmar, Shivam Shah, Ved Prakash ,Sudeep Patel, Dev Patel, Sudeep Desai, Jamal Rizvi , Harsh Patel, Beena Parikh, Kamal Kanodia, Shruti Gandhi, Michael A Rees,  Alvin E Roth,  Pranjal Modi “Impact of single centre kidney-exchange transplantation to increase living donor pool in India: A cohort study involving non-anonymous allocation,”Nephrology, September 2024,https://onlinelibrary.wiley.com/doi/10.1111/nep.14380

"Policy language: We suggest stepwise progress to achieve multicentre, regional, State and then a National program. Ideally, there should be engagement by the National Organ & Tissue Transplant Organization and the World Health Organization. 

While we recommend simultaneous surgery for mDRPs in a single exchange, sometimes logistical aspects have necessitated non-simultaneous exchanges"

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Earlier posts:

Thursday, August 8, 2024  Pediatric Heart Transplants: rethinking the waitlist, by Power, Sweat...Almond et al.

 Wednesday, September 18, 2024 More on non-anonymous kidney exchange in India

Behavioral market design (in the JEP)

 The Fall 2024 Journal of Economic Perspectives has three papers on behavioral market design:

Symposium: Behavioral Incentive Compatibility

6.	Evaluating Behavioral Incentive Compatibility: Insights from Experiments
	David Danz, Lise Vesterlund, and Alistair J. Wilson
	Full-Text PDF | Additional Information

 

Incentive compatibility is core to mechanism design. The success of auctions, matching algorithms, and voting systems all hinge on the ability to select incentives that make it in the individual's interest to reveal their type. But how do we test whether a mechanism that is designed to be incentive compatible is actually so in practice, particularly when faced with boundedly rational agents with nonstandard preferences? We review the many experimental tests that have been designed to assess behavioral incentive compatibility, separating them into two categories: indirect tests that evaluate behavior within the mechanism, and direct tests that assess how participants respond to the mechanism's incentives. Using belief elicitation as a running example, we show that the most popular elicitations are not behaviorally incentive compatible. In fact, the incentives used under these elicitations discourage rather than encourage truthful revelation.

 

7.	Behavioral Incentive Compatibility and Empirically Informed Welfare Analysis: An Introductory Guide
	Alex Rees-Jones
	Full-Text PDF | Additional Information

A growing body of research conducts welfare analysis that assumes behavioral incentive compatibility—that is, that behavior is governed by pursuit of incentives conditional on modeled imperfections in decision-making. In this article, I present several successful examples of studies that apply this approach and I use them to illustrate guidance for pursuing this type of analysis.

 

8.	Designing Simple Mechanisms
	Shengwu Li
	Full-Text PDF | Additional Information

It matters whether real-world mechanisms are simple. If participants cannot see that a mechanism is incentive-compatible, they may refuse to participate or may behave in ways that undermine the mechanism. There are several ways to formalize what it means for a mechanism to be "simple." This essay explains three of them, and suggests directions for future research.

Stability vs. No Justified Envy, by Romm, Roth and Shorrer

 Here's a recent paper that clarifies some of the prior literature on comparing stability in two-sided matching with a related kind of envy-freeness in allocations of goods to individuals using priorities.

Romm, Assaf, Alvin E. Roth, and Ran I. Shorrer, "Stability vs. No Justified Envy," Games and Economic Behavior, Volume 148, November 2024, Pages 357-366  https://doi.org/10.1016/j.geb.2024.10.002
 
Abstract: Stability and “no justified envy” are used almost synonymously in the matching theory literature. However, they are conceptually different and have logically separate properties. We generalize the definition of justified envy to environments with arbitrary school preferences, feasibility constraints, and contracts, and show that stable allocations may admit justified envy. When choice functions are substitutable, the outcome of the deferred acceptance algorithm is both stable and admits no justified envy.

Kim Krawiec interview about WHO demands for national self sufficiency in blood donation and kidney exchange

 The University of Virginia takes note of the recent Krawiec & Roth paper I blogged about in August.

Here is their interview with Kim about the paper:

WHO Stifles International Blood and Organ Donations, Argue Professors. Professor Kimberly Krawiec, Nobel Prize Winner Alvin E. Roth of Stanford Argue World Health Organization Policies Need Revision

Here are the first two Q&As

"What motivated you to critique the WHO principles of self-sufficiency and nonremuneration in organs and blood? ​

"The severe shortage of both blood products and transplantable organs, especially kidneys, was our motivation and has motivated much of our other work, both together and separately. In the United States alone, the organ transplant waiting list is approximately 100,000 people, and if current trends continue, it will only grow in the coming years.

"Shortages of blood products present a similar challenge. Although wealthy countries are typically able to satisfy domestic whole blood needs, the vast majority of low- and middle-income countries (LMIC) are not. As a result, in many LMIC, shortages of blood for transfusion contribute to maternal death, death from traffic accidents and complications from childhood anemia. Moreover, even wealthy countries experience seasonal shortages of whole blood or deficiencies in some blood components, such as platelets, which are harder to collect and have a shorter shelf life.

The shortage of plasma-derived medicinal products (PDMPs) is particularly severe and entirely preventable. PDMPs are life-saving treatments for multiple acute and chronic conditions for which there are no alternative treatments. Yet these life-saving therapies are unavailable to much of the world’s population. The United States, one of the few countries to pay plasma donors, supplies 70% of the world’s plasma needs, with Germany, Austria, Hungary, Czechia and Latvia (which also permit some form of payment for plasma donors) supplying another 20% of the world total. In other words, a handful of countries supply plasma to the rest of the world, including other wealthy countries. Meanwhile, LMIC who can neither collect and process their own nor afford to purchase blood products on the open market (or are prevented from doing so under the terms of the foreign aid that supports their health system) simply do without, to the detriment of their citizens.

"How do current WHO policies on organ and blood donation contribute to this problem?

"WHO policy mandates both national (or sometimes only regional) self-sufficiency and an absence of remuneration for both blood products and transplantable organs — what we refer to in the paper as “the twin principles.” These twin principles are unhelpful separately and unworkable together. Their effect on blood products is particularly stark — no country that fails to compensate donors is self-sufficient in plasma collection and few LMIC collect sufficient supplies of whole blood.

"The self-sufficiency mandate presents a real hurdle to progress in transplantation, especially for smaller countries and LMIC. This is especially the case because some of the most exciting and promising developments for increasing the availability of transplants have been in kidney exchange, a mechanism that leverages in-kind exchange, rather than financial compensation, to encourage and facilitate donation among those with willing but incompatible partners. But kidney exchange works best when a large pool of patient-donor pairs can engage with one another. So, requiring that transplantation be contained within national boundaries unnecessarily limits access to transplants that could be achieved only by cross-border exchange."

Many preference signals as a soft cap on number of applications in medical residency matching

 Here's a review article on matching for medical residents,  with particular attention to neurosurgery, in the Cureus Journal of Medical Science.  In specialties that (like neurosurgery) allow applicants to send many signals, many applicants signal to and match with programs with which they have some prior connection.

Ozair, Ahmad, Jacob T. Hanson, Donald K. Detchou, Matthew P. Blackwell, Abigail Jenkins, Marianne I. Tissot, Umaru Barrie et al. "Program Signaling and Geographic Preferences in the United States Residency Match for Neurosurgery." Cureus 16, no. 9 (2024).

Abstract: Postgraduate residency training has long been the cornerstone of academic medicine in the United States. The Electronic Residency Application Service (ERAS), managed by the Association of American Medical Colleges (AAMC), is the central residency application platform in the United States for most clinical specialties, with the National Residency Matching Program (NRMP) being the algorithm for matching residency programs with applicants. However, the determination of the best fit between ERAS applicants and programs has been increasingly challenged by the rising number of applicants per residency spot. This application overburdening across competitive specialties led to several adverse downstream effects, which affected all stakeholders. While several changes and proposals were made to rectify the issue of application overburdening, the 2020-2021 ERAS Match Cycle finally saw several competitive specialties, including otolaryngology and urology, utilize a new system of supplemental residency application based on preference signals/tokens. These tokens permit applicants to electronically signal a select number of programs in a specialty of choice, with the program reviewing the application now cognizant that they have been signaled, i.e., the applicant has chosen to use up a limited set of signals for their program. Initial results from otolaryngology and urology, as described in this article, indicated the value of this new system to both applicants and educators. Given the favorable outcomes and broader uptake of the system among other specialties, the field of neurosurgery adopted the utilization of the ERAS-based program signaling and geographic preference for the first time for the 2022-2023 Residency Application Cycle and later opted to continue them for the 2023-2024 and 2024-2025 cycles. For the 2024-2025 Match Cycle, neurosurgery applicants have 25 signals, i.e., a "high-signal" approach, where non-signaled programs have a low interview conversion rate. This literature review discusses the rationale behind the change, the outcomes of other competitive specialties from prior cycles, the evolving nature of the change, and the potential impact on applicants and programs. As we describe in this review, signaling may potentially represent a surrogate form of an application cap. Other considerations relate to cost savings for both applicants and programs from a high-signal approach in neurosurgery. These modifications represent a foundational attempt to alleviate the application overburdening and non-holistic review in the residency application process, including for neurosurgery. While these changes have been a welcomed addition for all stakeholders in residency match cycles so far, further prospectively directed surveys along with qualitative research studies are warranted to better delineate the downstream impact of these changes and guide further optimization of the application system.

A 40 year old proof about top trading cycles is corrected (by two Berkeley grad students)

 Science (and math) can be self-correcting, sometimes slowly.  Here's an article that corrects the first proof that the top trading cycles algorithm is group strategy proof.  That's a true result, with multiple subsequent proofs.  But apparently the first proof presented wasn't the best one.  That's good to know.

One reason this may have taken a long time to spot is that the result is correct, and that there are subsequent proofs that connect the result to properties of other mechanisms.  

Will Sandholtz and Andrew Tai, the authors, did this work as Ph.D. students at UC Berkeley. (good for them!)

Group incentive compatibility in a market with indivisible goods: A comment  by Will Sandholtz and Andrew Tai

"Highlights

• Bird (1984), first to show top trading cycles is group strategy-proof, has errors.

•We present corrected results and proofs.

•We present a novel proof of strong group strategy-proofness without non-bossiness.

"Abstract: We note that the proofs of Bird (1984), the first to show group strategy-proofness of top trading cycles (TTC), require correction. We provide a counterexample to a critical claim and present corrected proofs in the spirit of the originals. We also present a novel proof of strong group strategy-proofness using the corrected results."

More on non-anonymous kidney exchange in India

 Here's some further description of how kidney exchange is conducted in India without authorization* to use nondirected donors (so that all exchanges are conducted in cycles, i.e. in the absence of chains of exchange).

Vivek B. Kute, Himanshu V Patel, Subho Banerjee,Divyesh P Engineer, Ruchir B Dave, Nauka Shah, Sanshriti Chauhan ,Harishankar Meshram , Priyash Tambi  , Akash Shah, Khushboo Saxena,Manish Balwani , Vishal Parmar, Shivam Shah, Ved Prakash ,Sudeep Patel, Dev Patel, Sudeep Desai, Jamal Rizvi , Harsh Patel, Beena Parikh, Kamal Kanodia, Shruti Gandhi, Michael A Rees,  Alvin E Roth,  Pranjal Modi “Impact of single centre kidney-exchange transplantation to increase living donor pool in India: A cohort study involving non-anonymous allocation,”Nephrology, September 2024, https://onlinelibrary.wiley.com/doi/10.1111/nep.14380  

"In India, 85% of organ donations are from living donors and 15% are from deceased donors. One-third of living donors were rejected because of ABO or HLA incompatibility. Kidney exchange transplantation (KET) is a cost-effective and legal strategy to increase living donor kidney transplantation (LDKT) by 25%–35%.

"3.3 Non-anonymous allocation

"The THOA*, which regulates KET in India, is silent on the need for anonymity, so there is no legal requirement for anonymity in India, as compared with other countries, such as the Netherlands and Sweden. Our experience was that 90% of iDRP [incompatible Donor-Recipient Pairs] requested the opportunity to meet their matched donor and recipient pair (mDRP) and 10% asked the treating physician to decide if they should meet. None of the iDRP requested anonymity. Therefore, we have practiced absolute non-anonymity, meaning that all mDRPs meet and share medical reports after a potential exchange is identified, but before the formal allocation of pairs. If an iDRP requests anonymity, we would be willing to accommodate them, but to date, none have done so.

"Upon meeting with their mDRP, the iDRP can refuse the proposed exchange option without reason and continue to be on the waitlist and active in the KET pool. iDRPs must complete transplant fitness and legal documents required for transplant permission from the health authority before they are given the opportunity to meet their mDRP. A meeting between mDRPs occurs in the presence of a transplant physician, who can help solve any query before the proposed match is accepted by the involved pairs. iDRP are introduced to their mDRP prior to scheduling transplants to avoid chain collapse due to iDRP refusal of the mDRP. The mDRP shares medical reports of donors with each other, can also discuss with their other family members, and consults with their family physician/nephrologist before deciding whether to proceed. Living kidney donors are fully informed of perioperative and long-term risks before making their decision to donate. In India, donor age group matching is most commonly expected for all iDRP in the KAS."

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Earlier:

Monday, September 18, 2023

Kidney Paired Donation in Developing Countries: a Global Perspective

*Here's the THOA, THE TRANSPLANTATION OF HUMAN ORGANS AND TISSUES ACT, 1994

Simulating kidney exchange policies in Germany

 Here are a set of simulations designed to help Germany establish a national (rather than a fragmented) kidney exchange system.

Itai Ashlagi, Ágnes Cseh, David Manlove, Axel Ockenfels & William Pettersson,  Designing a kidney exchange program in Germany: simulations and recommendations. Central European Journal of Operations Research  (2024). https://doi.org/10.1007/s10100-024-00933-0

"Abstract: We examine some of the opportunities and challenges concerned with establishing a centralized national kidney exchange program in Germany. Despite the many advantages of a national program, without deliberate design and policy intervention, a fragmented kidney exchange program may emerge. We study a number of collaboration strategies, and resulting simulations suggest that transplant centers may find it advantageous not to fully participate, resulting in a net reduction in the number of transplants. These results also suggest that allowing more forms of kidney exchange, such as three-way exchanges and non-directed donations, can significantly increase the number of transplants while making participation in a national program more attractive and thus national coordination and cooperation more robust. We propose a multi-level policy approach that is easy to implement and would promote an efficient German kidney exchange program that benefits recipients, donors and hospitals."

...

The concluding sentence of the paper is:

"Germany should establish a robust, well-functioning national KEP that can be easily and straightforwardly integrated into an international KEP."

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Background:

Thursday, July 18, 2024

Kidney exchange in Germany: draft of a proposed law

Incentives matter for getting participation in clinical trials by low income households

 Here's a study that casts some light (via a randomized experiment) on the importance of incentives to get representative participation in clinical trials.

Nonrepresentativeness in Population Health Research: Evidence from a COVID-19 Antibody Study By Deniz Dutz, Michael Greenstone, Ali Hortaçsu, Santiago Lacouture, Magne Mogstad, Azeem M. Shaikh, Alexander Torgovitsky, and Winnie van Dijk, AER: Insights 2024, 6(3): 313–323, https://doi.org/10.1257/aeri.20230195

Abstract: "We analyze representativeness in a COVID-19 serological study with randomized participation incentives. We find large participation gaps by race and income when incentives are lower. High incentives increase participation rates for all groups but increase them more among underrepresented groups. High incentives restore representativeness on race and income and also on health variables likely to be correlated with seropositivity, such as the uninsured rate, hospitalization rates, and an aggregate COVID-19 risk index."

"We analyze representativeness in a unique COVID-19 serological study. Unlike most studies, the Representative Community Survey Project (RECOVER)COVID-19 serological study experimentally varied financial incentives for participation. The study was conducted on households in Chicago (the target population). Randomly sampled households were sent a package that contained a self-administered blood sample collection kit and were asked to return the sample by mail to be tested for the presence of COVID-19 antibodies (“seropositivity”). Households in the sample were randomly assigned one of three levels of financial compensation for participating in the study: $0, $100, or $500.

"We find that households in neighborhoods with high shares of minority and poor households are grossly underrepresented at lower incentive levels. High incentives increase participation rates for all groups but increase them more among underrepresented groups. A $500 incentive restores representativeness in terms of neighborhood-level race and poverty status. Representativeness is also restored in health variables likely to be correlated with seropositivity, such as the uninsured rate, hospitalization rates, and an aggregate COVID-19 risk index. Since incentives were randomly assigned and only revealed after the household was contacted, the noncontact rates at $0 and $100 should be the same as at $500, implying that differential hesitancy to participate is responsible for much of the nonrepresentativeness that we find at lower incentives.

"We are not aware of studies that randomize financial incentives in population health studies. It is well appreciated that racial minorities and lower-income households participate in health research at lower rates.1  The impact of incentives on survey participation rates conditional on demographic characteristics has been studied in the survey methodology literature (see Groves et al. 2009; Singer and Ye 2013, and references therein). The incentives used in this literature are typically an order of magnitude smaller than the incentives in the RECOVER study."

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Some earlier related posts:

Monday, February 22, 2021

Ethical Payment in Human Infection Challenge Studies in the American Journal of Bioethics

Monday, March 1, 2021

Compensating challenge vaccine trial participants: further discussion in the American Journal of Bioethics

Thursday, October 29, 2020

Paying participants in challenge trials of Covid-19 vaccines, by Ambuehl, Ockenfels, and Roth

"we note that increasing hourly pay by a risk-compensation percentage as proposed in the target article provides compensation proportional to risk only if the risk increases proportionally with the number of hours worked. (Some risky tasks take little time; imagine challenge trials to test bulletproof vests.) "

Sunday, November 1, 2020

What do we know about the effects of payments to participants in challenge trials for vaccines, and other public spirited activities?