Thursday, March 26, 2015

Redesigning the Israeli Medical Internship Match

Israel has a new system for allocating medical intern positions. It's quite different from the system in the U.S., in large part because hospitals are passive. Assaf Romm and Avinatan Hassidim are playing a big role in the design of several markets in Israel, and some papers just appeared on this one in the Israel Journal of Health Policy Research:

Original research article   Open Access
Slava Bronfman, Avinatan Hassidim, Arnon Afek, Assaf Romm, Rony Sherberk, Ayal Hassidim, Anda MasslerIsrael Journal of Health Policy Research 2015, 4:6 (20 March 2015)

Commentary   Open Access
Alvin E Roth, Ran I ShorrerIsrael Journal of Health Policy Research 2015, 4:11 (25 March 2015)

Assaf Romm writes:

"Every year about 500 medical students in Israel are assigned to 23 different hospitals in Israel for an internship (in Hebrew this phase is called סטאז') that lasts one year. Unlike the American market, in which both interns have preferences over being hired by different hospitals, and hospitals have preferences over hiring different resident, in Israel the market is one-sided, and hospitals (which are owned by the government) are not allowed to express their preferences. The reason for that is that the Ministry of Health (MoH) does not want the better medical students to do their internships in the big cities (Tel Aviv and Jerusalem) only, but instead prefers to scatter across the country. Then again, students do have diverse preferences because of family issues or other issues, and we would like to accommodate those preferences if possible. There is also the option of being matched as a couple, and in 2014 there were 24 couples in the market.

In the past the MoH employed the random serial dictatorship mechanism (RSD). Ex-post trades (with no monetary transfers) were allowed, which created a black market (with monetary transfers) for internships in Tel-Aviv and other highly demanded places. This led to MoH banning trading positions if one of the positions traded was ranked in the first to fourth places by the intern that received it through RSD.

Last year our team helped in redesigning the mechanism. The change was meant to improve the efficiency of the results, by moving from RSD which is ex-post efficient, to a mechanism which is rank-efficient (see Featherstone C., 2014, working paper). Using surveys we tried to assess interns' "utilities" from being assigned to differently ranked hospitals, and then we were able to maximize a linear program given those weights (while making sure, per the student body's demands, that no student's "utility" goes below her RSD allocation).

The interesting thing from a theory standpoint is that most of the algorithms that we know of and that provide an ordinally-efficient result require Birkhoff-von Neumann (BvN) decomposition. However, when there are couples in the market it can be shown that some matrices cannot be decomposed to a convex combination of valid "permutation" matrices. Furthermore, the problem of determining whether a matrix can be decomposed is NP-complete. We decided to consider algorithms that approximately decompose matrices, i.e., they result in a convex combination of valid matrices, but the sum of the combination is only very similar to the original matrix, and not exactly equal to the original matrix.

We were able to prove a lower bound on the distance between the approximation and the original matrix, and then came up with an approximation algorithm that manages to almost exactly hit this lower-bound. We tested the algorithm on actual data (and bootstrapped data) from recent years and showed it performs very well.

The new algorithm was deployed last year and was since used three times. The responses were very good, and we've also seen (as expected) a major improvement in rank distribution. MoH has agreed to continue running the new mechanism in the coming years. The student body related to the 2015 lottery also voted for continuing with the new mechanism. (We also ran a survey on medical interns that took part in the match, but unfortunately participation was very low.)

This project is summarized in two papers: the first one above in the IJHPR, and this one:

Redesigning the Israeli Medical Internship Match (Noga Alon, Slava Bronfman, Avinatan Hassidim and Assaf Romm) - Intended for Economics and CS audience. Includes detailed introduction about the market, analysis of interns' preferences, the NPC result, the approximation algorithm, and simulations that show performance on preference data."

Wednesday, March 25, 2015

A scary homophobia headline and story: repugnance is alive and well in California

It's not just anti-semites who speak of extermination (see David Brooks on that), anti-gays do too: here's a story just out in the NY Times. California Seeks to Head Off Initiative to Execute Gays

"The California attorney general, Kamala D. Harris, moved Wednesday to block a proposed voter initiative that would mandate the execution of sexually active gay men and women, calling it “patently unconstitutional” and a threat to public safety.
Ms. Harris said she would ask the state Superior Court in Sacramento to relieve her of having to write the title and summary for the Sodomite Suppression Act, which would clear the way for the author, Matthew G. McLaughlin, a lawyer in Huntington Beach, to begin gathering signatures to get it on the ballot.
The highly unusual announcement by Ms. Harris — by all appearances, California law gives no discretion to the attorney general in handling these kind of initiatives — comes as gay groups and others have called on her to block the measure. Ms. Harris, who was just elected to a second term, announced earlier this year that she would run for the Senate in 2016.
In her statement, Ms. Harris signaled her lack of legal options as she threw the ball to the courts. “If the court does not grant this relief,” she said, “my office will be forced to issue a title and summary for a proposal that seeks to legalize discrimination and vigilantism.”
Even if she is forced to proceed, Mr. McLaughlin — who did not return a telephone call seeking comment Wednesday — has a tough road ahead. He would have to gather the signatures of 365,880 registered voters, and it seems highly unlikely that if he succeeded at that, voters in the state would approve a measure like this."

School choice and medical residency matching in Forbes

I was in New York City yesterday for an IIPSC-organized conference on school choice, and it was a nice coincidence to see that Forbes had an article on school choice and other matching processes, that mentions IIPSC.

Prerna Sinha writes about deferred acceptance algorithms, in the medical match and in NYC high school choice: Quantifying Harmony: The Matchmaking Algorithm That Pairs Residents With Hospitals, Students With Schools

"In 2003 Professor Roth (Stanford), who has played a major role in the dissemination of the deferred acceptance algorithm, worked with Atila Abdulkadiroglu (Duke) and Parag Pathak (M.I.T.) to replace the broken high school match system that was previously in place in New York City.Roth realized similar to a stable marriage or residency-student match, a high school-student match would work if individuals and schools were permitted to select alternative options after their most preferred options were rejected.

He is confident that the deferred acceptance algorithm provides a significant improvement over the system that was previously in place, but he believes the school choice system could work better. He clarified, “... there is a problem with how to disseminate information to families about schools.” He also suggested that there would be less congestion and it would be a more efficient process if all charter schools and private schools participated too.
 Roth continues to work closely with Neil Dorosin, who was the director of high-school admissions in New York City at the time of the redesign. Dorosin is now the Executive Director of Institute of Innovation in Public School Choice (IIPSC), and Roth sits on the advisory board. IIPSC is a team of specialists in the design and implementation of enrollment and school choice systems. The organization helps communities integrate the latest market design research and technology to solve school choice problems.

Roth calls Dorosin the “Johnny Appleseed” of getting systems like the one in NYC into New Orleans, Denver, and Washington.

Dorosin told FORBES, “Public school choice, this two sided matching market where there are two interested parties (schools and students), exists all over the country, in every big city and most small cities too. In most cases the systems that are set up to organize that two sided matching market, unintentionally, are failing. Failing the kids and the families that are supposed to use them, failing the systems of schools that are supposed to be administering them.”

Private dealings between parents and schools, limited resources and information for some parties, and congestion caused by lack of centralized communication are examples of market malfunctions that lead to disorganized systems.

According to Dorosin, the market design approach (deferred acceptance) addresses the central problem of matching students with schools: high school seats are a scarce resource that needs to be allocated efficiently and transparently in a manner that allows students and parents to feel safe when participating.

Parents and students need to feel safe in listing their preferential choice of schools, free of fear that ranking School A as a top choice will hurt their chances of getting into School B, their second choice. Efficiency involves getting optimal results on the first try and avoiding numerous offers or back and forth between parties. Transparency would allow lottery numbers, school information, and reports about outcomes to be easily accessible by all in a centralized location.

Dorosin says, “These are the elements that lead to a better system. We call this universal enrollment.”

The deferred acceptance algorithm, which is the basis of Dorosin’s universal enrollment concept, has a proven track record with the students of New York City and medical residents across the country. It may yet have applications beyond those it has now. At the very least, you can expect urban districts around the country and possibly around the world to continue to adopt some of the principles."

Tuesday, March 24, 2015

A non-repugnant transaction that reads like a riddle, reflecting cultural changes

When I was in elementary school (yes, there were schools then), I more than once heard the following riddle, which was a sign of the times:
"a father and his son are in a car crash that kills the dad. The son is rushed to the hospital; just as he’s about to go under the knife, the surgeon says, “I can’t operate—that boy is my son!” How could this be?"

I thought of this riddle (and the role that conventional assumptions about gender roles play in it) when I saw this recent headline in the Telegraph:
Mary Portas: My brother is the 'father' of my son

The story answers the riddle in a way that indicates how much times have changed once again.

"Mary Portas has disclosed how her own brother helped her become a mother for the third time, after becoming a donor for an IVF procedure.

Portas, nicknamed the "Queen of Shops", has told how her wife Melanie Rickey became pregnant with their son thanks to help from her younger brother Lawrence."

Monday, March 23, 2015

The new economics of matching and market design, at Haverford

I'll be giving the Comanor Lecture at Haverford College today.

Here's the announcement:

The Economist as Engineer: The New Economics of Matching and Market Design, a talk by Nobel Laureate Al Roth, Professor of Economics at Stanford University, Monday, March 23rd, 2015 ~ 5:30pm, Sharpless Auditorium

Sunday, March 22, 2015

The market for breast milk

Should breast milk be bought and sold?

Andrew Pollack in the NY Times has the story:
Breast Milk Becomes a Commodity, With Mothers Caught Up in Debate

"Breast milk, that most ancient and fundamental of nourishments, is becoming an industrial commodity, and one of the newest frontiers of the biotechnology industry — even as concerns abound over this fast-growing business. The company that owns the factory, Prolacta Bioscience, has received $46 million in investments from life science venture capitalists.
"But the commercialization of breast milk makes many people uneasy. They worry that companies might capture most of the excess breast milk and make products that would be too costly for many babies, while leaving less milk available for nonprofit milk banks.

“The competition comes in the form of how much surplus breast milk is there in the country and who’s getting it,” said Kim Updegrove, executive director of the nonprofit Mothers’ Milk Bank at Austin. “The nonprofit milk banks have a long history of providing milk to the sickest babies, and provide it based on medical need and not on insurance reimbursement or financial resources.”

Debate is also intense over whether women should be paid for their milk or donate it altruistically. Opponents of payments, worried about breast milk “farming,” say women might try to increase their milk output unsafely, hide health problems that could make the milk unsafe, mix in cow milk to increase volume or deprive their own babies so they can sell more."

Here are my earlier posts on breast milk.

Saturday, March 21, 2015

Organ donation in Mexico: new campaign by the Carlos Slim Foundation

The Carlos Slim Foundation backs organ donation

"MEXICO CITY – Mexico isn’t living up to its potential when it comes to life-saving organ transplants that thousands of Mexicans need in order to continue living, said the Carlos Slim Foundation.

The foundation launched the 2015 “Héroes por la Vida” (Heroes for Life) campaign last month in a bid to encourage more Mexicans to talk with their families about donating their organs in the unfortunate event of their death.

“Today in Mexico, 19,000 people are waiting for an organ transplant,” Vanessa Slim de Hajj said at the campaign launch. “This number is growing every day, and the number of donors in our country is only 3.6 people for every 1,000.”

To put things into perspective, consider that in Spain, an international leader in transplants from cadavers, 36 of every 1,000 people are organ do- nors, 10 times the rate in Mexico. The national rate of postmortem trans- plants is less than many other Latin American countries as well.

“This campaign calls on Mexicans to be everyday heroes,” Slim said. “Today we can make a simple decision to save lives.”

On the campaign website (, volunteers can find information about how to register as a donor and order a donor card. However, the volunteer card isn’t a legally binding document and the ultimate decision falls to family as to whether their loved-one’s organs will be used to save lives.

and here: Campaña de donación: Héroes por la vida

Here's some background: the Slim family has personal experience with kidney transplantation: Slims’ Transplant Inspires Push for Organ Donations

Friday, March 20, 2015

Match Day 2015! 1,035 couples participated...

Congratulations to all the new docs!  Today was Match Day for the National Resident Matching Program (NRMP)

Here's a selection of stories that crossed my screen today:

Press Release: 2015 Residency Match Largest On Record With More Than 41,000 Applicants Vying For Over 30,000 Residency Positions In 4,756 Programs
" An all-time high of 1,035 couples participated in the Match, 110 more than last year, with a 94.8 percent match rate."

The fates of thousands of med school students are decided by this Nobel Prize winning algorithm

Match Day: Then & now

Matching Dreams: Students ring in the future of medicine on the first day of spring (Harvard)

Medical students open envelopes and glimpse their futures: A national event that places graduating medical students into residencies, Match Day is both a celebration and a nerve-wracking affair. (Stanford)

The residency match in Otolaryngology

A recent paper looks at the resident match in Otolarygology, in the context of the overall resident match.

State of Otolaryngology Match: Has Competition Increased since the ‘‘Early’’
Match?  by Cristina Cabrera-Muffly, Jeanelle Sheeder, and Mona Abaza, in the journal Otolaryngology--Head Neck Surgert 2015 Feb 24

"Over the past 60 years, the United States residency match process and characteristics of medical students applying to the match have changed considerably. Centralized matching of postgraduate training positions was successfully implemented nationwide in 1952.1 At that time, just over 10,000 positions were offered through the match. In the 2013 match cycle, there were almost 50 different specialties that offer PGY-1 positions through the National Residency Matching Program (NRMP) match and a total of 26,392 positions offered.2
In 2006, in response to concerns about physician shortages, the Association of American Medical Colleges (AAMC) recommended an increase in the number of medical student postions.3 There was an overwhelming response among allopathic programs in both new schools (13 have matriculated their first class since 2006) and larger class sizes in established schools, with rosters expanding 15% to 18%.3,4 Meanwhile, osteopathic medical schools have doubled in number from 15 to 30 over the past 20 years.3 Therefore, the overall number of graduating medical students has increased considerably, reaching an all-time high in 2013.5 This has a direct effect on the quantity of medical students seeking any residency position, including otolaryngology.
The otolaryngology match has also undergone several iterations since its beginnings. In late 1977, otolaryngology and ophthalmology specialties officially separated.6 In 2006, the otolaryngology match transitioned from coordination by the San Francisco match (SF match) to become part of the NRMP. This transition altered the timeline of the application process in otolaryngology and potentially affected the applicant pool. Prior to 2006, the interview season for early match was generally from October to December, with the rank list submission deadline in early January. Match notification occurred in mid-January.7 This allowed applicants who did not match to complete a separate application for other specialties, although interview periods often overlapped. Once the NRMP began coordinating the otolaryngology match in 2006, the interview season was delayed to November through January, with the rank list submission deadline at the end of February. Match notification now occurs in mid-March.8
The change from the SF match to the NRMP match occurred as the required general surgery intern year became integrated with otolaryngology residencies, eliminating the need to separately interview for a preliminary general surgery position.9 Since 2006, otolaryngology programs have an integrated intern year, eliminating the need for a separate match. The early timing of the otolaryngology match allowed for applicants who did not match into otolaryngology to apply for a different specialty during the regular match of the same year through the NRMP. Applicants participating in the couples match during the early match likely found it more difficult to coordinate match cities when one partner applied to otolaryngology and the other to a regular match specialty. It is unclear whether the competitive nature or the couples match situation was considered when the match timing was changed.
"Over the past 16 years, we have seen an increase in the number of US seniors applying to residency. Fortunately, during the same time period, the number of first-year residency positions in all NRMP specialties increased as well. This rate of growth of residency positions appears to be consistent with the recommendation by the Council on Graduate Medical Education, who recommended increasing the number of first-year residents to 27,000 per year by 2015.4 In the same time frame, the number of unfilled NRMP residency positions has decreased by 55.8%. These positions are being filled by non–US seniors since the overall rate of applications and matches increased while the rate of US senior applications and matches stayed constant. Non–US seniors include prior US medical school graduates and IMG. IMG includes both US citizens attending medical school outside the United States and citizens of other countries attending international medical schools. Data suggest that the IMG portion of this group is filling the additional residency positions. In 2002, 18.6% of all NRMP positions were filled by IMG, while in 2013, IMG matched into 24.8% of NRMP positions. Meanwhile, the percentage of NRMP positions filled by prior US graduates has remained stable (between 2% and 3%). The decrease in percentage of unfilled positions is also due to increased IMG matching.
"The advantages of the otolaryngology conventional match are the elimination of one of the interview processes (since the preliminary general surgery intern year is now included), as well as improved ability for couples to match together."