Tuesday, September 18, 2018

A school choice mechanism from Taiwan, by Dur, Pathak, Song and Sönmez

Deduction Dilemmas: The Taiwan Assignment Mechanism

Umut M. DurParag A. PathakFei SongTayfun Sönmez

NBER Working Paper No. 25024
Issued in September 2018
NBER Program(s):Economics of EducationLabor Studies 
This paper analyzes the properties of the Taiwan mechanism, used for high school placement nationwide starting in 2014. In the Taiwan mechanism, points are deducted from an applicant's score with larger penalties for lower ranked choices. Deduction makes the mechanism a new hybrid between the well-known Boston and deferred acceptance mechanisms. Our analysis sheds light on why Taiwan's new mechanism has led to massive nationwide demonstrations and why it nonetheless still remains in use.

 "Loosely  speaking,  in  Taiwan’s deduction system, a students priority is reduced based on the order in which preferences are ranked.  Table 1 lists the schedule of points employed in 2014 across the largest districts in Taiwan.  For instance, in Jibei, the largest district with over 60,000 applicants, a student’s score at her second choice is reduced by 1, the score at her third choice is reduced by 2, and so on.  In Yunlin district, no points are deducted for the first four choices, and 2 points are 3 deducted from choices five through eight. The deduction system has now been in place for the last five years, from 2014-2018."

This system of deductions is used to determine each student's priority at each school, and allocations are then determined, by a deferred acceptance algorithm, based on student preferences and these school priorities.

Monday, September 17, 2018

Kidney exchange scheduled to begin in Hong Kong

The South China Morning Post has the story:

New kidney donation scheme starts in October after change in Hong Kong law allows strangers to donate organs to patients
This is aimed at speeding up the long waiting time for a suitable organ and surgeries will be done at four of the city’s 43 public hospitals

"The paired organ donation arrangement, made legal after Hong Kong passed an amendment to its Human Organ Transplant Ordinance last month, allows a donor-patient pair who may not be a match for each other to donate organs to another donor-patient pair and vice versa, so that patients on both sides get the transplants they need.
"There is a huge supply-demand gap for kidney transplants in the city. As of June 30 this year, there were 2,214 patients on the transplant list in Hong Kong but each year there are only about 80 living or deceased donors. Two years ago the average waiting time for a kidney was over four years.
"Before the change in the law, strangers could not make live donations to transplant patients. Couples had to be married for more than three years and friends needed to obtain approval from the Department of Health’s Human Organ Transplant Board for live donations.

"Professor Philip Li, the chairman of the authority’s Central Renal Committee said in the UK and the Netherlands, the paired kidney donation programme was very mature and they were now having a very large number of successful matchings.

 “In Hong Kong, we are just starting, it will be quite a while before we actually see a significant effect,” Li said."

Sunday, September 16, 2018

The U.S. Chamber of Commerce honors ideas

Country songwriters Lee Thomas Miller and Wendell Mobley share some of their ideas and IP at the Ideas in Bloom party sponsored by the Chamber of Commerce

Last Wednesday I flew to Washington DC to join a Chamber of Commerce celebration of  ideas and intellectual property, in various categories.

The innovation awards are both for lines of work that the National Science Foundation funded, and they were introduced by the NSF director, Dr. France Córdova. (I am happy to go to DC to help showcase the great work that the NSF does...see my remarks at the end of this post.)

Here's a link to the announcement:

IP Champion for Excellence in Enforcement
Peter O’Doherty, Head, Economic Crime Directorate, City of London Police
Nick Court, Chief Detective, Police Intellectual Property Crime Unit, City of London Police

IP Champion for Excellence in Innovation
Alvin Roth, Founder, Kidney Exchange
Inderjit Jutla, Founder, Aluna

IP Champion for Excellence in Advocacy
Bart Herbison, President, Nashville Songwriters Association
Steve Bogart, Chairman, Nashville Songwriters Association

IP Champion for Excellence in Creativity
Kristie Macosko Krieger, Academy Award-nominated producer
Kira Goldberg, Executive Vice President, Production, 21st Century Fox

IP Champion for Excellence in IP Policy
Professor Liu Chuntian, Renmin University of China

IP Champion for Excellence in Innovation
Uzi Hanuni, CEO, Maxtech Networks

Musical Performance
Lee Thomas Miller, Nashville Mega-hit Songwriter
Wendell Mobley, Nashville Mega-hit Songwriter

And here's a link to a subsequent press release:

"IP Champion for Excellence in Innovation – Alvin Roth
"Since the first paired kidney exchange in 2000, thousands of people have received kidney transplants identified through paired exchanges."
I scored a personal max for (travel time)/(speaking time).  Here are my prepared remarks:

"I flew here today to say thank you: to the Chamber of Commerce for recognizing not just my work but also the role that the NSF plays in fostering scientific innovation. 

And thank you to the NSF, and particularly to the Social, Behavioral and Economic Sciences Directorate, which must be one of the most cost-effective investments the government makes.  Social science isn’t very expensive, but it can be incredibly valuable. It can save lives.

On a personal note, all of my work that was cited by the Nobel Prize committee was begun with funding from the NSF. Dan Newlon was the legendary director of the SBE Directorate, and he nurtured a generation of economists who made big changes in how economics is done. In the early 1990’s, when I was discouraged by the progress I was making on understanding matching, he encouraged me to stay the course. So for me, the NSF support was about much more than funding.

So:Thank you all for coming here tonight, thank you Dr. Córdova, thank you to the NSF for all your support, starting when I was very young, and thank you to the Chamber of Commerce."

Here's a video link (that seems to start only after the first minute or so, and the NSF section begins with Dr. Córdova at minute 1:33 and goes to 1:45...) 

Saturday, September 15, 2018

Envy free (not quite stable) matchings

It's hard for decentralized markets to achieve stable matchings (i.e. matchings with no blocking pairs) in the way that centralized clearinghouses can (and this is why we see some markets organized by clearinghouses).  So it's worthwhile looking at larger sets of outcomes, and in this paper we look at matchings such that any blocking pairs must involve an unfilled position--i.e. they are envy free in the sense that there are no blocking pairs in which some worker can take the job presently held by another worker.

Wu, Qingyun and Alvin E. Roth, “The Lattice of Envy-free Matchings,” Games and Economic Behavior, May 2018, 109, 201-211

The lattice of envy-free matchings


Envy-free matchings are matchings that can only be unstable with respect to a blocking pair of a worker with a firm that has some unfilled positions.
These envy-free but unstable matchings may arise in the course of filling “vacancy chains” following a worker's retirement.
The set of envy free matchings is a lattice under the partial ordering of the common preferences of the workers.


In a many-to-one matching model, we show that the set of envy-free matchings is a lattice. A Tarski operator on this lattice, which can be interpreted as modeling vacancy chains, has the set of stable matchings as its fixed points.
Here's an ungated version of the paper.

Friday, September 14, 2018

Economists and economics in tech companies, by Athey and Luca

Susan Athey and Mike Luca have a new paper about the job market for economists in tech companies, and about the jobs they do there:

Economists (and Economics) in Tech Companies

Abstract: As technology platforms have created new markets and new ways of acquiring information, economists have come to play an increasingly central role in tech companies – tackling problems such as platform design, strategy, pricing, and policy. Over the past five years, hundreds of PhD economists have accepted positions in the technology sector. In this paper, we explore the skills that PhD economists apply in tech companies, the companies that hire them, the types of problems that economists are currently working on, and the areas of academic research that have emerged in relation to these problems.

Thursday, September 13, 2018

The National Science Foundation's History Wall and Murals

The NSF's history wall consists of three murals, to provide "a visual history of the National Science Foundation (NSF), spanning nearly 7 decades of scientific discovery and innovation and depicting artist Nicolle R. Fuller's interpretation of NSF’s impact on the nation. "  Here they are, although they are in fact arranged horizontally, rather than vertically as below.  The murals have numbered sections (you can get a better look by clicking on each mural at the link above).  On the third mural, number 45 is
45. Breakthroughs in economics inspired new software that streamlines organ matches like kidney exchanges.

Here's a blowup of segment 45 representing kidney exchange:

Wednesday, September 12, 2018

School choice is expanding in Chile

School choice is expanding in Chile:

Sistema de Admisión Escolar comienza a operar en Tarapacá, Coquimbo, O’Higgins y Los Lagos
Google translate: School Admission System starts operating in Tarapacá, Coquimbo, O'Higgins and Los Lagos

"This Thursday, August 30, the applications for the new Admission System for Schools in the Tarapacá, Coquimbo, O'Higgins and Los Lagos regions begin.

"The new admission mechanism was designed by the Ministry of Education in conjunction with Industrial Engineering academics - Rafael Epstein, José Correa and Juan Escobar - as well as a team made up of master students, professionals, doctoral students abroad and post -docs

"Applied science, not tombola  (AT of GT 'tombola' = lottery)

"Applied successfully in the region of Magallanes since 2016, the new School Admission System is designed with scientific rigor and the assignment of students to schools is the result of the celebrated Deferred Assignment Algorithm 

Tuesday, September 11, 2018

Kidney exchange and computation

Here's an article on how computation--broadly characterized as artificial intelligence--has changed kidney transplantation. It gives some historical background on hard decisions, going back to the first dialysis machines and coming forward to kidney exchange, and has some discussion of  fairness

How AI changed organ donation in the US
By Corinne Purtill

"Today, multiple US hospitals run their own paired kidney donation programs. There are also three larger US exchanges that organize kidney chains across hospitals: the United Network for Organ Sharing, the National Kidney Registry, and the Alliance for Paired Kidney Donation. National exchanges are in place in the UK, Canada, and the Netherlands, and paired donations have taken place in hospitals from India to South Africa.
"Given the dearth of public education on what “artificial intelligence” actually means, hospitals and exchanges are wary of patients misconstruing the role algorithms play in identifying potential matches, perhaps fearing conjuring images of robots coldly issuing life-or-death edicts.

Machines currently do not decide which kidneys go where. Humans do that. The algorithms in place today can do the math more reliably and at greater scale than humans can, and implement the judgments humans have already made, but they don’t have a contextual understanding of why they are being asked to perform a calculation in the first place.
“In economics we talk about impossibility theorems. There are things you might want that are not possible to get,” Roth says. “When you’re allocating scarce resources, you can’t give a kidney to one person without failing to give it to someone else…. Computers will not lift the burden from humans in every respect.”

Monday, September 10, 2018

An illegal market for marijuana that enjoys effective local support in Copenhagen

The NY Times reports on the current state of affairs in "Christiania Freetown, the hippie commune in the center of Copenhagen." It's a tourist attraction, and also the home of an active market for marijuana, which is illegal in Denmark, but supported by the Christiania residents...

In Anarchic Corner of Copenhagen, Police and Dealers Play Cat and Mouse

"Christiania’s full-time residents, who number around 900, have their own system of self-regulation, including a strict ban on violence and hard drugs like heroin. The result is an uneasy equilibrium between drug dealers; residents of the commune, who have the power to expel the drug dealers; and their common adversary, the police."

Sunday, September 9, 2018

College admissions "customer relations management" software, and the marketing of Slate

The Chronicle of Higher Ed has a story about customer-relations management systems (CRMs) used by colleges to organize their marketing and admissions, focusing on one called Slate and how it sells itself to admissions officers:

A Tech Whiz Is Conquering College Admissions. It Takes Charm, Innovation, and Dancing Sharks.

"What is Slate? Technically, it’s a customer-relations management system, or CRM, which many colleges use to track data about prospective students and serve them customized information. Imagine a big virtual file cabinet full of such data, with a built-in brain that tells you how to act on it, responding to students’ interests and behaviors.

"Many admissions offices of all stripes rely on Slate for just about everything they do. Enrolling a freshman class requires relentless grunt work, and the system automates a great deal of it. An admissions officer who’s about to visit a high school can use Slate to send a text message to the cellphones of 20 prospective applicants there all at once.

Saturday, September 8, 2018

The first global kidney exchange: temporarily ungated link

Here's a shareable link to the paper below, which I blogged about earlier without having an ungated link. This link is good til October 27.
Along with the medical details of this successful kidney exchange chain, the paper shares some of the arguments we've heard suggesting that Global Kidney Exchange might be objectionable, and our replies, in considerable detail:)

Complete Chain of the First Global Kidney Exchange Transplant and 3-yr Follow-up



Global Kidney Exchange (GKE) offers an opportunity to expand living renal transplantation internationally to patients without financial means. These international pairs are entered into a US kidney exchange program that provides long-term financial support in an effort to identify opportunities for suitable exchanges for both these international pairs and US citizens.


While the promise of GKE is significant, it has been met with ethical criticism since its inception in 2015. This paper aims to demonstrate the selection process and provide >3 yr of follow-up on the first GKE donor and recipient from the Philippines.

About the link, Elsevier writes: 

To help you and the other authors access and share this work, we have created a Share Link – a personalized URL providing 50 days' free access to the article. Anyone clicking on this link before October 27, 2018 will be taken directly to the final version of your article on ScienceDirect, which they are welcome to read or download. No sign up, registration or fees are required.
Your personalized Share Link:

Friday, September 7, 2018

Societal Support for Paying Plasma Donors in Canada By Nicola Lacetera and Mario Macis

Here's a concise summary of recent work by Lacetera and Macis, as a Cato Institute Research Brief:

Societal Support for Paying Plasma Donors in Canada
By Nicola Lacetera and Mario Macis

They begin with a concise statement of why repugnance is important for economics:

"The legal status and regulation of economic transactions do not depend only on considerations regarding their economic efficiency, but also on whether a society supports the occurrence of trades through a price mechanism (if at all). Concerns that individuals engaging in certain transactions may be exploited or unduly influenced, that the terms of trade may not be fair, or that some transactions violate human dignity, the sanctity of life, or traditional institutions may lead a society to prohibit certain trades. These principles may take priority over material considerations and may contribute to defining common identities or a collective conscience that allows complex societies to be tied together. "

The article is "based on and includes excerpts from Nicola Lacetera and Mario Macis, “Moral NIMBY-ism? Understanding Societal Support for Monetary Compensation to Plasma Donors in Canada,” Law and Contemporary Problems 81 (2018): 83–105, https://scholarship.law.duke.edu/lcp/vol81/iss3/5.

Thursday, September 6, 2018

The DOJ may not get the last word on supervised injection sites

The WP has the story:
Cities defiant after Justice Department’s threat on ‘supervised injection sites

"Cities seeking to open sites where illegal drug users are monitored to prevent overdoses responded defiantly Tuesday to a Justice Department threat to take “swift and aggressive action” against that approach to the nationwide opioid epidemic.

"Plans for those “supervised injection sites” — under consideration in San Francisco, Philadelphia, New York City, Seattle and elsewhere — collided with a stern Justice Department warning issued last week, threatening to create a standoff between federal and local authorities like the confrontation over “sanctuary cities.”

As they have before, some liberal-leaning cities trying to cope with conditions on their streets find themselves at odds with more-restrictive Trump-era policy and enforcement.
More than 72,000 people died of drug overdoses in 2017, led by more than 49,000 deaths from opioids, according to preliminary statistics released last month by the Centers for Disease Control and Prevention."
Earlier related post:

Sunday, September 2, 2018

Wednesday, September 5, 2018

EconSpark: AEA Economics Discussion Forum

The AEA has launched a moderated discussion forum for issues of interest to economists, including (but not limited to) the Economics job market.

EconSpark: AEA Economics Discussion Forum

I just signed up (and tried my hand at answering a question:)

Repugnance watch: In Paris: are public urinals (for men) sexist?

The NY Times has the story:

With Tampons and Concrete, Vandals Hit Paris Urinals Seen as Sexist

"To some, the new street urinals in Paris are a mere eyesore, to say nothing of the men using them. To others, they are no less than an emblem of sexism, still more evidence that men’s needs are put above women’s."

Tuesday, September 4, 2018

Ignazio Marino on global kidney exchange

Ignazio Marino, the veteran transplant surgeon who also happens to have been Mayor of Rome, kindly shared with me this post from his blog.  He writes about kidney exchange and his hopes for global kidney exchange, pioneered by our colleague Mike Rees.  He writes about the great benefits that global kidney exchange could bring, and some of the international support it has received, but also about the fact that it has generated opposition in some quarters.

Here's his post:
Organ transplants: the revolutionary proposal of a Nobel Prize,
which concludes with these paragraphs:

"One of the objectives of the Global Kidney Exchange program is to provide quality health care , including but not limited to transplantation, for patients with end stage renal disease in the least developed countries, who would have no access to dialysis or transplantation. and would die.

"If I can transplant the kidney to an Italian patient because I find another compatible couple in Ethiopia, where a patient may not even have the possibility of hemodialysis, the person in Ethiopia will live because he will have a new kidney, and the person in Italy will live better - once transplanted - costing much less to the National Health Service. I think this is a good example of what in English is defined as a win win situation , in which everyone wins.

"However, there are criticisms. One of the concerns raised by great professionals like Francis Delmonico, professor emeritus at Harvard University, is how to control this international exchange of organs from an ethical and legal point of view.

"If an international chain of people is established, whose motive is always affection, but in which even people who are not always emotionally related come into play, there is the risk that the horrible crime of organ trafficking may in some way creep up.

"I believe the difference between the crime of organ trafficking in some countries and the idea behind the Global Kidney Exchange Program lies in the fact that this project is completely transparent, verifiable and controllable, and that transplants occur or would occur only in well-identified and qualified medical centers.

"The Global Kidney Exchange in 2017 had the endorsement of the American Society of Transplant Surgeons (the society that brings together all American surgeons in the transplant community). The first chain has already been built in the United States and success rate has been 100%.

"On 22 January 2018 the president of the Istituto Superiore di Sanità, Prof. Walter Ricciardi, in his role as a member of the Executive Board of the World Health Organization, promoted this idea.

"I am convinced that we should not be afraid of innovation simply because we are afraid of ourselves and of our inability to monitor ethical aspects. Especially when the benefit for human beings, rich or poor, regardless of citizenship, could be really great.""

Monday, September 3, 2018

The perils of (too) sharply reducing opioid prescriptions

The ongoing opioid epidemic in the U.S. (and elsewhere) has at least some of its origins in the over-prescription of opioid painkillers. So there is a lot of interest in how, and how much, to cut back on prescribing these drugs.  The two articles below raise some flags about cutting back too sharply, and warn of the long road ahead in any event (partly because people in chronic pain and people who have become addicted to prescription painkillers sometimes enter the market for illegal narcotics when they lose their prescriptions).

Sally Satel directs my attention to this article in Politico:

How the opioid crackdown is backfiring
Hundreds of chronic pain patients responding to a POLITICO survey describe being refused opioid prescriptions they had relied on for years with sometimes devastating consequences.

"Many of POLITICO’s respondents described being tapered off narcotics too quickly, or worse, turned away by doctors and left to navigate on their own. Some said they coped by using medical marijuana or CBD oil, an extract from marijuana or hemp plants; others turned to illicit street drugs despite the fear of buying fentanyl-laced heroin linked to soaring overdose death numbers. A few, like Fowlkes, contemplated suicide."

And here is an article by some of my Stanford colleagues that explores a model to make some predictions. It is forthcoming in The American Journal of Public Health (AJPH) (and published online first):

Modeling Health Benefits and Harms of Public Policy Responses to the US Opioid Epidemic
Allison L. Pitt, MS, Keith Humphreys, PhD, and Margaret L. Brandeau, PhD

"Objectives.To estimate health outcomes of policies to mitigate the opioid epidemic.

Methods.We used dynamic compartmental modeling of US adults, in various pain,opioid use, and opioid addiction health states, to project addiction-related deaths, lifeyears, and quality-adjusted life years from 2016 to 2025 for 11 policy responses tothe opioid epidemic.

Results.Over 5 years, increasing naloxone availability, promoting needle exchange,expanding medication-assisted addiction treatment, and increasing psychosocial treatment increased life years and quality-adjusted life years and reduced deaths. Other policies reduced opioid prescription supply and related deaths but led some addicted prescription users to switch to heroin use, which increased heroin-related deaths. Over a longer horizon, some such policies may avert enough new addiction to outweigh the harms. No single policy is likely to substantially reduce deaths over 5 to 10 years.

Conclusions.Policies focused on services for addicted people improve population health without harming any groups. Policies that reduce the prescription opioid supply may increase heroin use and reduce quality of life in the short term, but in the long term could generate positive health benefits. A portfolio of interventions will be needed for eventual mitigation. (Am J Public Health.Published online ahead of print August 23,2018: e1–e7. doi:10.2105/AJPH.2018.304590)"

Note the contrast between these views and those of the Department of Justice as expressed by Deputy Attorney General Rod Rosenstein in yesterday's post.

Sunday, September 2, 2018

The DOJ argues against harm reduction measures for drug addicts

In an opinion piece in the NY Times, Rod Rosenstein,  the deputy attorney general of the United States, comes out against harm reduction measures for drug addiction, such as those being considered in several U.S. cities and States.  He argues that increased prosecution is the way to go, and threatens to go after cities that institute "safe injection sites."

Fight Drug Abuse, Don’t Subsidize It
Americans struggling with addiction need treatment and reduced access to deadly drugs. They do not need a taxpayer-sponsored haven to shoot up.

By Rod J. Rosenstein

"Last year, San Francisco assembled a task force to establish an injection site, and last week the California State Senate passed a bill that would allow San Francisco to operate such sites and grant legal immunity to the drug users who visit them. In May, the mayor of New York City announced a plan to open four injection sites. A Seattle task force approved a similar plan, and city officials have pitched outfitting a van as a mobile injection site. Numerous states, including Colorado, Massachusetts, Vermont and Maine, have explored similar options to help their residents use hard-core drugs.

"One obvious problem with injection sites is that they are illegal. It is a federal felony to maintain any location for the purpose of facilitating illicit drug use. Violations are punishable by up to 20 years in prison, hefty fines and forfeiture of the property used in the criminal activity. The law also authorizes the federal government to obtain civil injunctions against violators. Because federal law clearly prohibits injection sites, cities and counties should expect the Department of Justice to meet the opening of any injection site with swift and aggressive action.
"To end the drug crisis, we should educate everyone about the dangers of opioid drugs, help drug users get treatment and aggressively prosecute criminals who supply the deadly poison. Under the leadership of President Trump and Attorney General Jeff Sessions, the Department of Justice is delivering results. Many federal, state and local agencies are working with us to combat opioid addiction. Cities and counties should join us and fight drug abuse, not subsidize it."

Here are my other posts on harm reduction.

Saturday, September 1, 2018

Market design class at Harvard taught by Scott Kominers

If you are a Harvard student, check out Scott Kominer's Fall market design class.
Here's the course outline.

Market Design

Economics 2099 -- Harvard University -- Fall 2018 
This course explores the theory and practice of market design. Key topics include auctions, labor market matching, school choice programs, online markets, organ exchange systems, financial market design, and matching with contracts. The first half of the course will introduce market design and its technology; subsequent weeks will discuss recent papers alongside their classical antecedents.

Information on Logistics, Requirements, and Readings:
See the course syllabus (posted August 29, 2018).

Enrollment Application:

Assignment Deadlines:
A short proposal summary/plan will be due on October 17, 2018. The final proposal will be due on December 10, 2018 (the last day of Reading Period).

September 4, 2018Introduction/Overview
September 11, 2018The Market Designer's Toolbox
September 18, 2018Food Supply, Scrip Systems, and
Erica Moszkowski
September 25, 2018School Choice
October 2, 2018Generalized MatchingRavi Jagadeesan
October 9, 2018Markets for Intellectual Property
October 16, 2018Auction TheoryShengwu Li
October 23, 2018The US Spectrum Incentive Auction
October 30, 2018Organ Allocation
November 6, 2018Finance, Cryptocurrency, and
November 13, 2018Inequality and Urban IssuesEdward L. Glaeser
November 20, 2018New HorizonsZoë Cullen, Andrey Fradkin
David Parkes, Utku Ünver,
Kate Vredenburgh
November 27, 2018Refugees, Immigration, and
Economic Development
Benjamin Roth
December 4, 2018Student Talks/Course Wrap
Internal Harvard Website:

Office Hours Calendar: