Sunday, March 29, 2015

A proliferation of single-center kidney exchanges

Kidney exchange is becoming a very standard part of kidney transplantation in the United States, which is good news. But, as more and more transplant centers gain experience with kidney exchange, a good deal of it is being conducted within single centers: i.e. among the patients at a single hospital.

This is mixed news...since even more transplants can be achieved in thicker markets.

Here are some of the recent, celebratory announcements about exchanges and chains at Yale, in New Haven, and California Pacific Medical Center in San Francisco ...

8 patients, 4 kidney exchanges, all in one day at Yale New Haven Hospital

Members Of Successful 8-Person Organ Exchange Meet, Feel Like One Big Family


THE SCIENCE BEHIND A CRAZY 6-WAY KIDNEY EXCHANGE

Saturday, March 28, 2015

In Canada, Doctors worry how organ donations will be affected by Supreme Court ruling on assisted suicide

Here's the story from the National Post
Doctors worry how organ donations will be affected by Supreme Court ruling on assisted suicide

"As the nation awaits legalized doctor-assisted death, the transplant community is grappling with a potential new source of life-saving organs — offered by patients who have chosen to die.

"Some surgeons say every effort should be made to respect the dying wishes of people seeking assisted death, once the Supreme Court of Canada ruling comes into effect next year, including the desire to donate their organs.

"But the prospect of combining two separate requests — doctor-assisted suicide and organ donation — is creating profound unease for others. Some worry those contemplating assisted suicide might feel a societal pressure to carry through with the act so that others might live, or that it could undermine struggling efforts to increase Canada’s mediocre donor rate.

“Given the controversy and divided opinion regarding physician-assisted suicide in Canada, I don’t think we are anywhere near being ready to procure the organs of patients who might choose this path,” said Dr. Andreas Kramer, medical director of the Southern Alberta Organ and Tissue Donation Program in Calgary.


“I think there is a legitimate possibility that advocating aggressively for this could compromise the trust that the Canadian public has in current organ-donation processes,” Dr. Kramer said.
...
"Organ harvesting after doctor-assisted death is already a reality in Belgium, which became the second country in the world, after the Netherlands, to legalize voluntary euthanasia in 2002.

"In 2011, Belgian surgeons reported the first lung transplants using lungs recovered from four donors put to death by lethal injection. All — two patients with multiple sclerosis, one with a neurological disorder and the other a mental illness — explicitly and voluntarily expressed their wish to become an organ donor after their request for euthanasia was granted, the team reported.

“We now have experience with seven lung donors after euthanasia,” Dr. Dirk van Raemdonck, a surgeon from University Hospitals Leuven, told the National Post. “All recipients are doing well.”

Lungs, as well as kidneys and livers, have been retrieved and transplanted from a total of 17 euthanasia donors, Dr. van Raemdonck said. The results will be presented next week at the annual meeting of the Belgian Transplantation Society in Brussels."

Friday, March 27, 2015

Are we nearing a turning point for doctor-assisted suicide/death with dignity?

The NY Times has a thoughtful piece looking back at recent changes, and considering what hasn't changed:  Stigma Around Physician-Assisted Dying Lingers

"Five states, in various forms, countenance doctor-assisted dying. Others are considering it. In California, legislation to permit such assistance is scheduled to receive a hearing this week. A lawsuit in New York that seeks a similar result was filed in State Supreme Court last month by a group of doctors and dying patients. The emotional wallop of these issues is self-evident, and it is captured in the latest installment of Retro Report, a series of video documentaries that explore major news stories of the past — looking back at where we have been to see where we may be headed.
...
"Arguments, pro and con, have not changed much over the years. Assisted dying was and is anathema to many religious leaders, notably in the Roman Catholic Church. For the American Medical Association, it remains “fundamentally incompatible with the physician’s role as healer.”
Some opponents express slippery-slope concerns: that certain patients might feel they owe it to their overburdened families to call it quits. That the poor and the uninsured, disproportionately, will have their lives cut short. That medication might be prescribed for the mentally incompetent. That doctors might move too readily to bring an end to those in the throes of depression. “We should address what would give them purpose, not give them a handful of pills,” Dr. Ezekiel Emanuel, a prominent oncologist and medical ethicist, told Retro Report.
But to those in the other camp, the slippery-slope arguments are overwrought. Citing available information from the few jurisdictions where assisted dying is permitted, supporters of “dying with dignity” laws say that those looking for an early exit tend to be relatively well off and well educated. There is no evidence, they say, to suggest that such laws have been used promiscuously by either patients or their doctors. As for the medical association’s ethical judgment, it “focuses too much on the physician, and not enough on the patient,” said Dr. Marcia Angell, a former executive editor of The New England Journal of Medicine. Writing in The New York Review of Books in 2012, Dr. Angell asked, “Why should anyone — the state, the medical profession, or anyone else — presume to tell someone else how much suffering they must endure as their life is ending?”

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