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