Monday, December 20, 2010

Mathematics and medicine: a cautionary tale

Mathematics is valuable in many areas of application, including medicine, but there are hazards to having doctors diagnose their own mathematical needs. A hilarious example was just brought to my attention; a well-cited medical paper that reinvents one of the first lessons of high school calculus (which the author goes on to name after himself):
A mathematical model for the determination of total area under glucose tolerance and other metabolic curves. by M M Tai, Diabetes Care February 1994 vol. 17 no. 2 152-154 .

Here's the abstract in its entirety:
"OBJECTIVE--To develop a mathematical model for the determination of total areas under curves from various metabolic studies. RESEARCH DESIGN AND METHODS--In Tai's Model, the total area under a curve is computed by dividing the area under the curve between two designated values on the X-axis (abscissas) into small segments (rectangles and triangles) whose areas can be accurately calculated from their respective geometrical formulas. The total sum of these individual areas thus represents the total area under the curve. Validity of the model is established by comparing total areas obtained from this model to these same areas obtained from graphic method (less than +/- 0.4%). Other formulas widely applied by researchers under- or overestimated total area under a metabolic curve by a great margin. RESULTS--Tai's model proves to be able to 1) determine total area under a curve with precision; 2) calculate area with varied shapes that may or may not intercept on one or both X/Y axes; 3) estimate total area under a curve plotted against varied time intervals (abscissas), whereas other formulas only allow the same time interval; and 4) compare total areas of metabolic curves produced by different studies. CONCLUSIONS--The Tai model allows flexibility in experimental conditions, which means, in the case of the glucose-response curve, samples can be taken with differing time intervals and total area under the curve can still be determined with precision. "

Google Scholar reveals that this paper is Cited by 137, most of which appear to be un-ironic.

Incidentally, while scholars like to properly reference things, who knows if the world would be better if the author had cited a calculus textbook, and pointed out that this method had been well known for hundreds of years. Very likely the medical journal would have declined to publish it if they had realized it wasn't new. (It says something about the difficulty a medical journal faces in evaluating mathematical ideas that none of the referees recognized this.) And the citations the paper has received suggest that at least to some subsequent researchers, this elementary calculus lesson, delivered in a medical journal, filled a gap in their education and proved useful. On the other hand, if the paper had instead pointed out that there is lots of widely available software to do numerical integration, it might have been even more useful to docs who needed to find areas under curves.

One of the delights of interdisciplinary work is how fruitful it can be. This is particularly true in market design, which almost always involves work between economists and experts in other things who are  directly involved in some market.

One of the frustrations of interdisciplinary work is that it involves translation between different cultures. For example, parts of market design are fairly mathematical, or involve ideas from economics (e.g. about incentives) that may be unfamiliar to non-economists.

My work on kidney exchange has had more than its share of both the delights and the frustrations, in part because the non-economist experts involved--kidney surgeons--are so very expert at what they do. I've had the good fortune to be part of teams of market designers and surgeons who work really well together.

But the translation barrier to the rest of the medical profession is formidable, particularly because matching for kidney exchange is quite mathematical, and doctors are mostly selected for their talents in other things. This makes for great complementarities when you find the right docs, but it's always hard for the medical journals to evaluate contributions that have an element of mathematics, and things can go badly wrong when a doctor overestimates the breadth of his competency, which is an occupational hazard for people whose daily work involves giving advice to patients whose lives depend on it.

HT: Assaf Romm

Sunday, December 19, 2010

Prizes for solutions to problems

An Australian firm, Kaggle, hosts problem solving and prediction competitions, and describes itself this way: "Kaggle is an innovative solution for statistical/analytics outsourcing. ...Companies, governments and researchers present datasets and problems - the world's best data scientists then compete to produce the best solutions. At the end of a competition, the competition host pays prize money in exchange for the intellectual property behind the winning model."

One of their current competitions requires participants to predict travel time on Sydney's M4 freeway from past travel time observations.

Other approaches for eliciting solutions to problems by offering prizes are found at Innocentive, and Challenge.gov, both of which list problems for which people can offer solutions for evaluation.

Saturday, December 18, 2010

The end of 'don't ask don't tell...'

Senate Repeals ‘Don’t Ask, Don’t Tell’


Another formerly repugnant transaction bites the dust...

The World Bank goes all in on carbon markets

The NY Times reports: World Bank Will Help Finance Carbon Markets

"As the United Nations climate change talks in Cancún lurch slowly toward an uncertain conclusion, the World Bank is stepping in to help developing countries set up pollution credit markets to help pay for clean development programs.

"Robert B. Zoellick, the World Bank president, will appear before delegates here on Wednesday to announce the creation of a multimillion-dollar program to create trading mechanisms to stimulate clean energy projects and to slow the destruction of tropical forests, one of the primary sources of global warming emissions. ...
...
"The list of countries that will take part in the carbon market initiative was not announced, but they are expected to include China, Mexico, Indonesia and Chile. Other countries are expected to join as more funds become available, bank officials said.

"The European Union already has a carbon market, known as the Emissions Trading System, which barters pollution credits for European industries for climate-friendly projects, mainly in the developing world. Legislation to create a similar national trading system in the United States stalled in Congress this year.

"Such programs are controversial because they have been at times poorly monitored and the price for carbon credits has fluctuated wildly. Many poorer nations also complain that their natural resources have been turned into commodities traded on exchanges in wealthy countries.

“Carbon markets are an irreparably flawed means of addressing climate change,” Karen Orenstein of the environmental group Friends of the Earth told Reuters. “They are unreliable and subject to fraud, and they open the door to offset loopholes that undermine environmental integrity.”

"The World Bank hopes to devote as much as $100 million to provide technical support and other aid to help developing countries establish carbon exchanges and other ways of raising private funds to help reduce emissions and adapt to climate changes."

Friday, December 17, 2010

Bone marrow donor scam

I've blogged before about bone marrow donation, but recent news stories report what appears to be a financial scam by a bone marrow registry.
Officials rip health chain’s aggressive bone-marrow campaign

"Condemning the practice as a scam involving “suspect marketing and billing practices,’’ New Hampshire Attorney General Michael A. Delany yesterday announced a major probe of shopping-mall bone marrow donor recruitment drives by UMass Memorial and its subsidiary, the Caitlin Raymond International Registry.
James T. Boffetti, New Hampshire senior assistant attorney general, said in a telephone interview yesterday afternoon that his office will investigate potential criminal violations of New Hampshire’s Consumer Protection Act as part of a joint probe with the state’s Insurance Department.
Caitlin Raymond staff and the models from a Boston agency, which charged UMass Memorial between $40,000 and $50,000 a week for about a year and a half, told potential donors that the DNA test required to join the registry did not cost anything, Boffetti said.
However, UMass Memorial billed the potential donors’ insurance companies as much as $4,300 per test, far more than the roughly $100 charged by most labs, according to Boffetti."

Update: here's a more sympathetic story: Surge in marrow testing probed


The job market for assistant professors in marketing

That's the title of a new paper by César Zamudio, Yu Wang, and Ernan Haruvy, which looks at the market for marketers as a two sided matching problem.

Here's the abstract:
"We measure the value of different types of matches between job candidates and marketing departments by applying a structural two-sided matching model to a dataset of placements in the entry-level marketing professor job market in 1997 – 2005. Our results show that a match between a candidate trained in a particular field and a department with comparable faculty is not always the most valuable match. We find evidence for publications serving as quality signals for job candidates, especially publications in top marketing journals. Author positions close to the first and a large number of co-authors seem to be valuable signals of job candidates’ research productivity. Finally, matches between candidates who graduated from top ranked departments and top ranked hiring departments generate especially high matching values."

They write about the somewhat complicated unraveling they see in the market:
"The expertise structure of the marketing arena has caused the hiring process within each field to unravel differently. This is a consequence of the way research productivity is judged by marketing faculty from different fields. As of today, most candidates have defended their dissertation proposals by the time they participate in the market. CB [consumer behavior] and strategy job candidates are often expected to have multiple finished projects in their research pipeline, preferably submitted to top journals, by the time they participate in the market. This expectation requires that the candidate be involved in projects which are in advanced planning stages, and pursue active collaborations with senior faculty members. Modeling candidates, however, are only expected to have constructed a plan for their dissertation, along with preliminary results. This is because modeling articles often have a longer time to submission and the review process is considerably slower. Thus, modeling departments hire based on the promise of each candidate’s research proposal. To summarize, depending on the candidate’s field, he or she may be evaluated based on a promise of a planned project, or based on a rich portfolio of finished projects in which the candidate’s relative contribution is unknown.

Thursday, December 16, 2010

Transplantable organs: the worst and best systems

A grim story is playing out as European investigators finish an investigation: The NY Times reports
"A two-year international inquiry has concluded that the prime minister of Kosovo led a clan of criminal entrepreneurs whose activities included trafficking in organs extracted from Serbian prisoners executed during the Kosovo conflict in 1999."


This story is the takeoff point for another, much more hopeful story at Slate, pointed out to me by Benjamin Kay of UCSD: The Kidney Trade: Can economists make the system for organ transplants more humane and efficient?



It touches on kidney exchange, and compensation for donors, among other things.

Wednesday, December 15, 2010

Outsourcing reproduction

The WSJ has an article on Assembling the Global Baby
"With an international network of surrogate mothers and egg and sperm donors, a new industry is emerging to produce children on the cheap and outside the reach of restrictive laws."

"In a hospital room on the Greek island of Crete with views of a sapphire sea lapping at ancient fortress walls, a Bulgarian woman plans to deliver a baby whose biological mother is an anonymous European egg donor, whose father is Italian, and whose birth is being orchestrated from Los Angeles.

"She won't be keeping the child. The parents-to-be—an infertile Italian woman and her husband (who provided the sperm)—will take custody of the baby this summer, on the day of birth.

"The birth mother is Katia Antonova, a surrogate. She emigrated to Greece from Bulgaria and is a waitress with a husband and three children of her own. She will use the money from her surrogacy to send at least one of her own children to university.

"The man bringing together this disparate group is Rudy Rupak, chief executive of PlanetHospital.com LLC, a California company that searches the globe to find the components for its business line. The business, in this case, is creating babies.

"Mr. Rupak is a pioneer in a controversial field at the crossroads of reproductive technology and international adoption. Prospective parents put off by the rigor of traditional adoptions are bypassing that system by producing babies of their own—often using an egg donor from one country, a sperm donor from another, and a surrogate who will deliver in a third country to make what some industry participants call "a world baby."

"They turn to PlanetHospital and a handful of other companies. "We take care of all aspects of the process, like a concierge service," says Mr. Rupak, a 41-year-old Canadian.
...
"PlanetHospital's most affordable package, the "India bundle," buys an egg donor, four embryo transfers into four separate surrogate mothers, room and board for the surrogate, and a car and driver for the parents-to-be when they travel to India to pick up the baby.

"Pricier packages add services like splitting eggs from the same donor to fertilize with different sperm, so children of gay couples can share a genetic mother. In Panama, twins cost an extra $5,000; for another $6,500 you can choose a child's gender.
...
"Greek surrogacy is regulated by a 2005 law, but the business takes advantage of a legal loophole. Surrogate mothers are not supposed to act for profit. However, they can accept money for pregnancy-related expenses. Typically, the expenses are set at up to $50,000.

"The judge never asks" about the money, says Maria Kouloumprakis, a surrogacy lawyer in Greece. Ms. Kouloumprakis calls the situation "an emptiness in the law."

"Egg donors often come from the U.S. or Eastern European countries since white parents tend to prefer fair-skinned children. Those countries allow donor anonymity. Parents on tighter budgets might opt for a donor from India or Latin America. Sperm is often provided by the fathers-to-be, though it's also available from a network of sperm banks in the U.S. and Europe.
...
"Many factors drive surrogacy's global spread. China and other big adoption destinations have toughened their rules in recent years. Some developed countries, including Japan, Spain, Germany, Italy and France, outlaw or severely restrict surrogacy at home. The United Kingdom prohibits surrogacy for pay, and in 2005 banned donor anonymity. Some U.S. states prohibit surrogacy for pay, and in recent years some have outlawed gay adoption.
...
"[In India, a] couple made payments as the pregnancy progressed, with the final amount due at birth. Of the $35,000, PlanetHospital keeps around $3,600. Another $5,000 goes to the egg donor, plus another $3,000 or so for travel expenses. The surrogate gets $8,000. The rest, around $15,000, is paid to the clinic.
...
"No country has become a greater magnet for the business than India, which made surrogacy legal in 2002. It has an ample supply of inexpensive surrogates and egg donors. There is little regulation beyond guidelines that set age limits for surrogates and prohibit a woman from acting as a surrogate more than three times.
...
"Surrogacy's complexity can give rise to extraordinarily difficult decisions, such as whether or not to abort. This can happen because clinics sometimes implant multiple embryos into multiple surrogates to improve the odds: If one miscarries, there are still viable pregnancies. However, if several implants successfully lead to pregnancy, clients face ending up with not just one or two children, but many."

And here is the PlanetHospital website--they are involved in all sorts of "medical tourism," not just reproductive services.

Tuesday, December 14, 2010

Misc. organ transplant links: poetry and priority

Steve Leider points me to this video about all of the people who received transplant organs from Chris Henry, the wide receiver who died in a vehicle accident last year. Apparently his mother brought them all together recently.


All those organ recipients from one donor made me thing of this kidney transplant poem that (along with others by the same author) is reported by the Los Angeles Examiner:  Los Angeles Poet G. Murray Thomas, an essential voice in a city where noone is ever doubting Thomas (HT gtaniwaki )

“YOUR KIDNEY JUST ARRIVED AT LAX”

"The doctor told me as I lay in pre-op prep.
I envisioned a special chartered flight,
an entire airplane filled with organs.

"Hearts with little heart shaped carry-ons.
They always watch the inflight movie
and cry all the way through.

"Livers splurging on one last drink;
they don’t think they’ll be allowed
where they’re going.

"The lungs eye the spot
where the oxygen masks drop.

"Corneas stare out at the passing countryside;
they always get a window seat.

"The spleens are always complaining

about security
about the length of the flight
about the lack of leg room
(although they have no legs).
"The gall bladder always gets in line
before his row is called.

"And there’s my kidney,
no doubt reading a book to pass the time
something classic: As I Lay Dying,
or Great Expectations,
or The Stranger.

"All of them wondering
about the journey ahead,
about their new home,
about their new life."

-G Murray Thomas


In other news, the Israeli priority rule is going into effect: Registered donors to get preference if they need organ

"...the Health Ministry’s Israel Transplant will “give priority” in the receipt of organs to people who previously signed an ADI card and gave consent to donate organs after their deaths.

"Their immediate family members will also be entitled to this benefit.

"The new policy, which is being promoted by a twoweek media campaign that began on Sunday, is aimed at narrowing the gap between the 10 percent of Israelis who are registered as potential donors with ADI and the 62% who, when polled, said they were willing to donate lifesaving organs after they die.

"The 2008 organ transplant law included a unique section that gives priority to ADI card holders and their immediate relatives who need a transplant organ. However, due to the need for many technical and other preparations, it has taken more than two years to launch the new policy, which was approved by a majority of experts.

"Anyone already registered with ADI or who signs up before December 31, 2011 will be entitled to the priority benefit starting on January 1, 2012, while anyone joining after December 31, 2011 will be entitled to the benefit from three years after the date of signing, according to Israel Transplant, which is chaired by Rambam Medical Center director-general Prof. Rafael Beyar.

"Tamar Ashkenazi, Israel Transplant’s long-time coordinator, said that she hopes the “bonus” will induce hundreds of thousands of people – from the age of 17 – to register with ADI as potential organ donors. Today, only 547,000 people, or 10% of the population of the requisite age, are registered. ADI is an organization named for Adi Ben-Dror, who died decades ago from the lack of a donor kidney.

"Ashkenazi noted that there are two computerized lists of people who need organ transplants, one of those in hospital who urgently need an organ and the other living at home who need one less urgently. Having an ADI card would give “additional points” that are allocated and, through computers, automatically calculate who is most suited for a specific organ among those of a compatible blood type. “The extra points will be a significant addition to those who urgently need an organ,” she said.

"For a few weeks after the media campaign ends, stands will remain in public places for signing up new ADI members."

Monday, December 13, 2010

Admissions blogs

At this time of year, lots of people are thinking about admissions to colleges and universities, both as undergraduates and graduate students. Many admissions offices now have blogs (Google searches provide big lists here and here, and another useful meta-list of advice and commentary is here).

Admissions office blogs reflect two things:
  • first, admissions in many places is highly selective, that is, the schools and programs get more applicants than they can admit and must select among them;
  • second, admitted students must be wooed, as they are mostly admitted to more than one school or program.
So admissions is a great example of a matching market: neither side of the market can just choose what they want, they also have to be chosen.

This is especially true at the most competitive programs: e.g. locally, here are the blogs from the HBS doctoral program, the HBS MBA program, and the Harvard law school. The undergrad admissions offices at both Harvard and MIT support student bloggers.

Someone recently pointed out to me that the HBS doctoral program blog featured a nice paragraph about me; and it's certainly true that for many applicants who are interested in an Economics Ph.D. from Harvard it makes sense to apply to  Bus-Ec as well as to Economics (or vice versa), since the two programs have separate admissions committees, and there's a good deal of randomness in the process of selecting a very small group of admits from a very large group of exceptionally accomplished applicants.

Sunday, December 12, 2010

College football is big business (who knew?)

The Chronicle reports on just how big a business college football has become  With an Assist From Alabama, Southeastern Conference Breaks the $1-Billion Mark

"Thanks to a lucrative television contract and robust earnings generated by several highly ranked football teams, the 12 athletic programs in the league brought in $1,006,798,094 during the 2009-10 fiscal year, according to new data from the Education Department. That's about an 11-percent increase from the previous year and a nearly 77-percent bump from six years ago.
The league's biggest boost came from the University of Alabama, where revenues spiked by 24 percent in 2009-10, to $129.3-million. With its increase, Alabama leapfrogged Ohio State University and the University of Florida to reach No. 2 on the list of biggest revenue-producing programs in all of college sports. The University of Texas, which brought in $143.6-million, remains No. 1."
...
"Still, as revenues have grown, so have expenses: Even though each of the top 20 moneymakers in college sports pulled in more than $75-million last year—eight programs alone made more than $100-million—that doesn't mean all of them turned a profit. Of the 120 athletic programs in Division I-A, all but 14 operated with a deficit*. (For a list of the top 100 earners, see this LSU fan blog, which first reported on the conference's crossing the billion-dollar mark.)"

*"Institutions in Division I-A, which include some of the biggest and wealthiest athletics programs in the NCAA, allocated a median of $10.2-million to their athletic departments in the 2009 fiscal year, according to the NCAA’s annual analysis of Division I financial data. That allocation was an increase from the median of $8-million that universities provided to sports program during the previous year."

Saturday, December 11, 2010

First transplants from national kidney exchange in the U.S.

UNOS announces First Kidney Paired Donor Transplants Performed as Part of National Pilot Program

"Ken Crowder of St. Louis and Kathy Niedzwiecki of Pelham, N.H., are experiencing renewed life and health thanks to the generosity of two living kidney donors

"Rebecca Burkes of St. Louis had intended to be a living donor for her fiance, Mr. Crowder, and Cathy Richard of Henniker, N.H., had planned to donate to her sister-in-law, Ms. Niedzwiecki -- only to find that both were medically incompatible with their intended recipient. But in the first paired donation arranged through a national pilot program of the Organ Procurement and Transplantation Network (OPTN), Ms. Burkes was able to donate to Ms. Niedzwiecki and Ms. Richard became a donor for Mr. Crowder.

"Paired donation is helping the transplant community help people who otherwise could not get a living donor transplant. We're proud to be able to coordinate these for the first time using a national network for potential matches among 77 participating transplant programs," said OPTN/UNOS president Charles Alexander, RN, M.S.N., M.B.A. United Network for Organ Sharing (UNOS) operates the OPTN under federal contract.

"The donor recovery and transplant operations all took place Dec. 6. Mr. Crowder received a transplant at Barnes-Jewish Hospital in St. Louis and Ms. Niedzwiecki was transplanted at Dartmouth-Hitchcock Medical Center in Lebanon, N.H. Ms. Burkes donated her kidney at Barnes-Jewish and Ms. Richard underwent surgery at Dartmouth-Hitchcock.

"Drs. Surendra Shenoy and Jason Wellen performed the donor and recipient surgeries at Barnes-Jewish.

"Paired kidney exchange programs have allowed for a significant increase in the number of patients that receive a living kidney transplant, therefore freeing up additional deceased donor kidneys for the 80,000 plus people on the national wait list," said Dr. Wellen, surgical director of the Washington University/Barnes-Jewish kidney and kidney/pancreas transplant program. "A nationally run paired exchange program will allow for many new donor/recipient matches to take place that would otherwise not have been available through smaller-run paired exchange programs."

"Dr. David A. Axelrod, section chief of transplantation surgery at Dartmouth-Hitchcock, performed both the donor and transplant operations at his center. "We all realize that the shortage of donors is only getting worse," he commented. "One solution is to expand the accessibility to live donor transplants. The innovation here is an increasing pool of potential donor-recipient pairs. Expanding the database of willing and able live donors, at the local, regional, and national level through programs like this pilot, enables us to maximize access to this precious resource."

"The kidneys were preserved for transportation by the New England Organ Bank and Mid-America Transplant Services. Angel Flight NE also provided air transportation to and from Dartmouth-Hitchcock. "We are not only very excited, but more importantly honored to be part of this historic event," said Larry Camerlin, President of Angel Flight NE. "By participating in this type of program, it speaks to our organization's mission of bringing journeys of healing and hope to those in need and ensure that they get the care and support they require."

"The donors and recipients were paired according to the first computerized match run conducted by the OPTN in October 2010. Each transplant program participating in the pilot program submits detailed medical information on potential living donors and candidates to an affiliated coordinating center, which works directly with UNOS on administrative issues such as enrolling donor/recipient pairs, making logistical arrangements and entering data. Johns Hopkins Hospital served as the coordinating center for Mr. Crowder and Ms. Burkes; the New England Program for Kidney Exchange (NEPKE) was the coordinating center for Ms. Richard and Ms. Niedzwiecki.

"We are extraordinarily grateful for the work of the coordinating centers, each of which also arranges kidney paired donations within its own network of transplant programs," said Mr. Alexander of the OPTN and UNOS. "The goal of the pilot project is to see whether combining the data of multiple centers and networks will generate successful matches that may not be found through one individual organization. The fact that these transplants occurred from the first match run suggests this will be true."

"Future match runs will be conducted every four to five weeks with information on potential living donors and candidates supplied by pilot participants. Each transplant program will make individual medical decisions about accepting living donors or candidates and whether they qualify for matching through the pilot program. In addition, each program must document that potential living donors have undergone a rigorous medical screening and have provided detailed informed consent for donation and for potential participation in a national match run.

"The following websites provide additional information:
For the Barnes-Jewish Hospital kidney transplant program: http://www.barnesjewish.org/kidney-transplant
For the Dartmouth-Hitchcock Medical Center transplant center: http://www.dhmc.org/goto/Transplant
For the OPTN kidney paired donation pilot program: http://optn.transplant.hrsa.gov/resources/KPDPP.asp

"The Organ Procurement and Transplantation Network (OPTN) is operated under contract with the U.S. Department of Health and Human Services, Health Resources and Services Administration, Division of Transplantation by the United Network for Organ Sharing (UNOS). The OPTN brings together medical professionals, transplant recipients and donor families to develop organ transplantation policy."

And here's the Boston Globe story in connection with the patient who entered through the New England Program for Kidney Exchange. NH woman gets kidney through new donor-matching program

Updates: further stories and links:
About the Angel program pilots: Kidneys and Gyros in Pittsburgh (good catch by Larry Hosken in the comments, and see my previous post Angel donors and angel flights in a NEPKE kidney exchange chain
Link to the program: http://optn.transplant.hrsa.gov/resources/KPDPP.asp

Friday, December 10, 2010

Time share markets for vacation housing

Ernan Haruvy and Yu Wang explore some market design issues that arise in vacation house exchange, theoretically and experimentally, in their paper Tiers in Consumer Fractional Ownership Markets. Their idea is that unless the market maker restricts the trading rights of owners of undesirable properties, the market may eventually suffer from a form of unraveling in which people buy inexpensive properties in an attempt to gain access to more expensive properties.

Here's the abstract:
"In consumer fractional ownership markets such as timesharing in vacation homes and sharing programs for luxury products, consumers purchase a share in a property and can later exchange its usage right with other owners through secondary matching markets. In such programs, consumers may attempt to game the system by purchasing inexpensive low quality shares and trading up afterwards. Such behavior may cause the collapse of the primary sales market. We investigate a tiered structure that restricts trading up. The analysis focuses on two commonly used matching mechanisms in the marketplace – Deposit First and Request First mechanisms. In laboratory experiments we find that when the matching market does not have a tiered structure, the Request First mechanism performs significantly worse than the Deposit First mechanism, whereas the tiered matching structure performs equally well under both mechanisms. Consistent with the theory, tiered matching that restricts upgrading is shown to simultaneously restore primary sales and facilitate exchanges among owners. A change in market structure requires some adjustment, but over time participants learn to adopt theoretically optimal strategies. Entry into matching markets is below theoretical predictions and this is shown to be partly due to risk aversion."

They describe the underlying marketplace institutions:
"In this industry, households purchase timeshare properties and can then exchange their usage rights in a one-to-one matching market. Some of the matching markets are run by property developers themselves (e.g., Timbers Resorts). One can think of these companies as vertically-integrated players in both the primary sales market and the secondary matching market. Some other matching markets are operated by third-party match-making companies such as Resort Condominium International.  These match-making firms do not build resort properties but create platforms for property owners to make exchanges. With either type of market maker (vertically-integrated property developers or third-party match-making companies), to make exchanges timeshare owners typically search in a depository of properties called a space bank. The space bank can be seen as a match-making firm’s inventory of properties. Owners can “deposit” their property into the space bank and “withdraw” a different property from it. Thus, the space bank is the key feature of the one-sided matching market under investigation, as it serves the important purpose of facilitating exchanges among the owners."
...
"Two matching mechanisms have been widely adopted in the timeshare matching market (Wang and Krishna 2006): the Deposit First (DF) mechanism and the Request First (RF) mechanism. To initiate an exchange in a DF market, households must first deposit their own properties into the space bank. In other words, the household cannot inspect the space bank until it has given up the usage right of its own property. Thus, successful withdrawal is not guaranteed by the company, as one may end up with a worse property than her original one. In fact, one of the main complaints about the DF mechanism is the risk of becoming worse-off (ex post) as a result of exchanges. On the other hand, in an RF market households deposit their own properties only after they have withdrawn a preferred property from the space bank. If there is no good alternative in the space bank, households can choose to keep their original properties."

They also consider the connection to kidney exchange...

Thursday, December 9, 2010

The former science of anthropology

Economics is a social science, dedicated to studying human beings as they interact with each other. It isn't the only social science, we keep company in that regard with political scientists, sociologists, some kinds of psychologists and historians, and of course, anthropologists. But that "of course" is misplaced, following the recent decision of the American Anthropological Association to drop "science" from parts of its self-description: Anthropology A Science? The Experts Disagree

"Anthropologists have been thrown into turmoil about the nature and future of their profession after a decision by the American Anthropological Association at its recent annual meeting to strip the word “science” from a statement of its long-range plan.

"The decision has reopened a long-simmering tension between researchers in science-based anthropological disciplines — including archaeologists, physical anthropologists and some cultural anthropologists — and members of the profession who study race, ethnicity and gender and see themselves as advocates for native peoples or human rights."


Of course, science by any other name could still be scientific, and scientifically inclined anthropologists will still go about their business. The first paragraph of the Association's statement says
"The purposes of the Association shall be to advance public understanding of humankind in all its aspects. This includes, but is not limited to, archaeological, biological, social, cultural, economic, political, historical, medical, visual, and linguistic anthropological research.  The Association also commits itself to further the professional interests of anthropologists, including the dissemination of anthropological knowledge, expertise, and interpretation."


Update, Dec. 13: The Times reports Anthropology Group Tries to Soothe Tempers After Dropping the Word ‘Science’
"On Monday, the association issued a statement of clarification, saying it recognizes “the crucial place of the scientific method in much anthropological research.”
...
""There has been a longstanding cultural gap within the association between the evidence-based researchers, who include some social anthropologists, and those more interested in advocating for the rights of women or native peoples. The new long-range plan, approved last month, inflamed these differences. "

Civil Unions for same sex couples in Illinois

Civil Unions Advance in Illinois
"Illinois lawmakers on Wednesday approved legislation allowing civil unions in this state, and the governor has indicated he will sign it, making Illinois one of only a handful of states to grant to same-sex couples a broad array of legal rights and responsibilities similar to those of marriage.
"Advocates of the legislation, who had pressed the matter for years, pointed to the outcome as a sign that acceptance of gay men and lesbians is growing and not only on the coasts.


Sober, clear-minded, cautious Midwesterners are taking this action,” said Rick Garcia of Equality Illinois, a gay-rights group.
"Opponents complained about the timing of the vote (during a fall session before newly elected legislators arrive) and said they feared civil union legislation might ultimately harm the institution of marriage. “This will be the entry to a slippery slope,” Ron Stephens, a Republican state representative, said. “The next thing we’ll see will be consideration of gay marriage.”

"Five states and the District of Columbia allow same-sex marriage, while New Jersey grants civil unions similar to the measure expected to take effect here in July. Four other states grant domestic partnerships with broad legal rights — bonds that some experts said carry many of the rights provided under Illinois’s new legislation if not the precise ceremonial recognition suggested by civil union.

"The Illinois provision will provide couples many legal protections now granted to married couples, including emergency medical decision-making powers and inheritance rights. The legislation allows heterosexual couples to seek civil unions, too.

Wednesday, December 8, 2010

National kidney exchange in Canada

Here's a recent announcement from Canadian Blood Services: Kidney Exchange Registry Goes National, Living Donor Paired Exchange becomes first Canada-wide organ donation registry

"OTTAWA, ON - November 30, 2010 -- Yesterday, the Living Donor Paired Exchange performed the first match run to include kidney patients and donors from all across Canada. In doing so, it became the first Canada-wide organ donation registry.

"The LDPE registry facilitates living kidney donations between patients with a willing but incompatible donor and another pair in the same situation. It is a partnership between Canadian Blood Services and transplant programs across the country, and was launched as a three-province pilot in January 2009. Since then, all other provinces have gradually joined the registry, and with Quebec firming up its participation in October, the initiative has become Canada-wide in scope.


"The inclusion of all provinces in the LDPE is a significant development for patients as it increases the pool of donors. And of course the larger the pool, the more likely patients are to find a match and receive the transplant they need," said Dr. Graham Sher, CEO, Canadian Blood Services. "This is a prime example of how better collaboration and integration can improve donation and transplantation rates in this country, and ultimately, save more lives. It is what sets top performing countries apart."

"The LDPE has registered 185 donor/recipient pairs from across the country, and has been responsible for facilitating 57 kidney transplants since the launch with an additional 16 scheduled for surgery in the weeks ahead.

"Critical to the registry's success has been the inclusion of non-directed donors - a person who is entered into the registry, unpaired and willing to donate to any one in need. "Non-directed donors are selfless heroes that have created 'domino exchanges' which are responsible for 45 of the 57 transplants to date," said Dr. Ed Cole, Chair of the National Kidney Registries Advisory Committee and University Health Network Physician-in-Chief. "Non-directed donors greatly increase the number of available matches, but best of all, since they enter as a single rather than a pair, it means that at the end of the domino chain, one patient on the deceased donor waiting list also gets a transplant."

Tuesday, December 7, 2010

School districts face a multitude of problems

My colleagues and I mostly interact with municipal school districts regarding questions of school choice. But of course school boards and districts have to deal with a whole multitude of problems, some of which sometimes impact their school choice decisions (either directly, or just because some problems are even more pressing).

In NY, Class Sizes Grew in City Despite ’07 Deal to Cut Them.
And here's a story, that in discussing opposition to Mayor Bloomberg's newly nominated schools Chancellor, also provides a good summary of the size of the changes he and Chancellor Joel Klein tackled: Frustrations With Mayor Are Backdrop to Nominee Uproar
     "Mr. Klein took office soon after the State Legislature handed the mayor control of the school system — no one yet knew how it would play out, and few would have imagined the scope of the overhaul that the mayor has since engineered. Mr. Bloomberg had yet to dissolve the 32 school districts that were a bedrock of the system and that, while chronically corrupt in some places, were also a crucial lifeline for parents with questions and concerns.
     "Sure, people who follow such things knew that the Board of Education, once a hotbed of political squabbling, would be replaced by a panel whose majority would be appointed by the mayor. But no one foresaw that if the mayor’s appointees disagreed with his policies they would be fired, as two were on the eve of a controversial panel vote in 2004, rendering the panel toothless. Now that it is clear that mayoral control really means mayoral control, the question of who would execute the mayor’s wishes has taken on more importance. "

Boston also has serious budget problems, which directly affect school choice: School officials in Hub urge closings
"The scenarios following Superintendent Carol R. Johnson’s recommendations last month to close several schools represent the stark realities confronting the school system as it prepares for its fourth consecutive year of budget cutting. The district is projecting a $63 million shortfall for the school year beginning September 2011. Last night, officials said the 2012-13 school year could be even worse, with an anticipated $91 million shortfall...
"The 40-minute financial presentation last night did little to quell the protests from the schools recommended for closure: the East Zone Learning Center, Emerson Elementary, Clap Elementary, Social Justice Academy, and the Engineering School in Hyde Park....
"In January, the school district is expected to raise once again the divisive issue of changing the way the district assigns students to schools after a similar attempt failed two years ago amid public uproar. The effort is intended to reduce busing costs by shrinking the geographic regions from which families can choose schools. If the district comes up with a palatable plan, any savings are not expected to be realized for at least two years."

and
More schools targeted to close in Hub
"The School Committee is slated to vote Dec. 15 on Johnson’s proposal. The committee needs to act quickly because next month parents start submitting their choices of where they want to send their children to school next fall.
...
"But some of those buildings might not sit empty for long. In a separate announcement late yesterday afternoon, Johnson and Mayor Thomas M. Menino said some buildings may be leased to charter schools, which are planning an aggressive expansion in the city."

In San Francisco, there are problems on the school district staff: San Francisco School Administrators Schemed to Take Money, Documents Say
"A group of San Francisco Unified School District administrators, including an associate superintendent, engaged in a long-running scheme to funnel district money into their personal bank accounts via nonprofit community organizations, according to internal documents. "
In short, market design takes place, when it does, amidst a noisy, difficult background, particularly in tough financial times.

Monday, December 6, 2010

Kidney sales and incentives for donors: current controversy

The American Journal of Transplantation has over the past year been full of surveys about the attitudes of various groups towards compensation of organ donors, including particularly live kidney donors. The groups surveyed have included transplant surgeons, the general public, kidney patients, and kidney donors. The surveys reveal a great deal of variance within groups, but a surprising willingness across groups to consider various kinds of compensation for donors, especially when subject to government regulation. So there's at least a suggestion that some kinds of payment to donors may one day become a "formerly repugnant transaction," i.e. it seems that its status as a repugnant transaction may be shifting.

The discussion was punctuated by a signed editorial, with a surprisingly contemptuous tone, called “Kidneys for Sale: Whose Attitudes Matter?”  It took the point of view that kidney transplantation is a business run by kidney surgeons, and that no one else's opinions should be consulted on matters of health policy related to kidney patients.

This is an especially surprising view given that kidney disease is treated very specially by Medicare, to the great benefit of kidney patients (as well as kidney surgeons). (Medicare is financed primarily by payroll taxes and general tax revenues, as well as premia paid by beneficiaries, and it presently spends about $8 billion a year on dialysis, for example; see Medpac for good Medicare background).

But the view of the editorialists that kidney transplantation is only about surgeons seems to be a fringe view (certainly not shared by the surgeons I've had an opportunity to work with on kidney exchange, although they have varied opinions on donor compensation). Subsequent letters to the AJT rebuked the editorialists, not only for their contemptuousness, but also for misrepresenting the data from the survey of transplant surgeons.

Below are the citations, with abstracts of the articles, and excerpts from the editorial and letters, since those don't have abstracts.

Stimulus for Organ Donation: A Survey of the American Society of Transplant Surgeons Membership by J. R. Rodrigue, K. Crist, J. P. Roberts, R. B. Freeman Jr., R. M. Merion and A. I. Reed, Am J Transplant 2009; 9 (September): 2172–176.
     "Federal legislation has been proposed to modify the National Organ Transplant Act in a way that would permit government-regulated strategies, including financial incentives, to be implemented and evaluated. The Council and Ethics Committee of the American Society of Transplant Surgeons conducted a brief webbased survey of itsmembers’ (n = 449, 41.6% response rate) views on acceptable or unacceptable strategies to increase organ donation. The majority of the membership supports reimbursement for funeral expenses, an income tax credit on the final return of a deceased donor and an income tax credit for registering as an organ donor as strategies for increasing deceased donation. Payment for lost wages, guaranteed health insurance and an income tax credit are strategies most strongly supported by the membership to increase living donation. For both deceased and living donation, the membership is mostly opposed to cash payments to donors, their estates or to next-of-kin. There is strong support for a government-regulated trial to evaluate the potential benefits and harms of financial incentives for both deceased and living donation. Overall, there is strong support within the ASTS membership for changes to NOTA that would permit the implementation and careful evaluation of indirect, government-regulated strategies to increase organ donation."

"How Different Conceptions of Risk Are Used in the Organ Market Debate," by A. Aronsohn, J. R. Thistlethwaite, Jr., D. L. Segev, and L. F. Ross, American Journal of Transplantation, 10, 4, 931-937, APR 2010
"The success of kidney and liver transplantation is hindered by a shortage of organs available for transplantation. Although currently illegal in nearly all parts of the world, a living 'donor' or 'vendor' kidney market has been proposed as a means to reduce or even end this shortage. Physician members of the American Society of Transplantation, the American Society of Transplant Surgeons and the American Association for the Study of Liver Disease were surveyed regarding organ markets for both living kidney and living liver transplantation. The survey queried respondents about their attitudes toward directed living donation, nondirected living donation, the potential legalization of living donor organ markets and the reasons for their support or opposition to organ markets. Partial or completed surveys were returned by 346 of 697 eligible respondents (50%). While virtually all supported or strongly supported directed living donation (98% and 95% for kidney and liver lobes, respectively), the vast majority disagreed or strongly disagreed with the legalization of living donor organ markets (80% for kidneys and 90% for liver lobes). Both those who support and those who oppose a legalized living donor organ market rate risk to the donor among the most important factors to justify their position."


Leider, Stephen and Alvin E. Roth, “Kidneys for sale: Who disapproves, and why?” American Journal of Transplantation, 10 (May), 2010, 1221-1227.
     "The shortage of transplant kidneys has spurred debate about legalizing monetary payments to donors to increase the number of available kidneys. However, buying and selling organs faces widespread disapproval.
We survey a representative sample of Americans to assess disapproval for several forms of kidney market, and to understand why individuals disapprove by identifying factors that predict disapproval, including disapproval of markets for other body parts, dislike of increased scope for markets and distrust of markets generally. Our results suggest that while the public is potentially receptive to compensating kidney donors, among those who oppose it, general disapproval toward certain kinds of transactions is at least as important as concern about specific policy details. Between 51% and 63% of respondents approve of the various potential kidney markets we investigate, and between 42% and 58% want such markets to be legal. A total of 38% of respondents disapprove of at least one market.
Respondents who distrust markets generally are not more disapproving of kidneymarkets; however we find significant correlations between kidney market disapproval and attitudes reflecting disapproval toward certain transactions—including both other body markets andmarket encroachment into traditionally nonmarket exchanges, such as food preparation."


Patient Willingness to Pay for a Kidney for Transplantation, by D. K. Herold,
American Journal of Transplantation, Volume 10, Issue 6, pages 1394–1400, June 2010
     "While kidney transplantation is the most cost-effective treatment available for end-stage renal disease (ESRD) and affords patients with the best quality of life, the current supply of kidneys does not meet the demand. A potential solution to increasing the supply is to compensate living donors for a kidney. The purpose of this study was to describe ESRD patient willingness to pay for a kidney. Using a self-administered survey, 107 patients in 31 U.S. states completed the survey. The quantitative method and descriptive survey design employed descriptive, correlational, nonparametric and multivariate statistical tests to evaluate the data. Of participants, 78.5% were willing to pay for a kidney; there were significant correlations between gender, health status, household income, preferred source of a kidney and willingness to pay. Men, patients with poor and fair health status and those with household incomes ≥$50 000 were more willing to pay. Step-wise regression analysis found price and doctor’s influence accounting for 52% of variance in willingness to pay. As price increased and doctor’s opinion mattered, willingness to pay increased. This study supports development of additional studies with
larger sample sizes and patients on kidney transplant waiting lists."

 
"For Love or Money? Attitudes Toward Financial Incentives Among Actual Living Kidney Donors", by M. C. Van Buren, E. K. Massey, L. Maasdam, W. C. Zuidema, M. T. Hilhorst, J. N. IJzermans and W. Weimar, American Journal of Transplantation, Volume 10, Issue 11, pages 2488–2492, November 2010
     "Due to lengthening waiting lists for kidney transplantation, a debate has emerged as to whether financial incentives should be used to stimulate living kidney donation. In recent surveys among the general public approximately 25% was in favor of financial incentives
while the majority was opposed or undecided. In the present study, we investigated the opinion of living kidney donors regarding financial incentives for living kidney donation. We asked 250 living kidney donors whether they, in retrospect, would have wanted a financial reward for their donation.We also investigated whether theywere in favor of using financial incentives in a government-controlled system to stimulate living anonymous donation. Additionally, the type of incentive deemed most appropriate was also investigated.
In general almost half (46%) of the study population were positive toward introducing financial incentives for living donors. The majority (78%) was not in favor of any kind of reward for themselves as they had donated out of love for the recipient or out of altruistic principles. Remarkably, 60% of the donorswere in favor of a financial incentive for individuals donating anonymously. A reduced premium or free health insurance was the preferred incentive."

And here is the editorial against finding out what non-surgeons think:

D. L. Segev and S. E. Gentry “Kidneys for Sale: Whose Attitudes Matter?” American Journal of Transplantation 2010; 10: 1113–1114
"...Should we devote resources to investigating the nuances of public attitudes toward these markets? Probably not, for two major reasons."
"First, nothing else is relevant until physicians support organ sales....
"Second, and more importantly from a logistical standpoint, is that it will take an act of Congress—that is the reversal of the National Organ Transplant Act (NOTA) of 1984—to make organ markets a reality. And this act will be nearly impossible to come by."

And the following two entries are letters to the editor objecting to the Segev-Gentry editorial, the first by Arthur Matas (a kidney transplant surgeon and former president of the American Society of Transplant Surgeons), the second by Sally Satel, a doctor, kidney recipient, and commentator working at the American Enterprise Institute.

A. J. Matas, Department of Surgery, University of Minnesota
"Markets or Incentives: Terminology Is Critical," American Journal of Transplantation 2010; 10: 2374
     "I am disappointed in Segev and Gentry’s Editorial (1) regarding Leider and Roth’s survey, which was recently published in The American Journal of Transplantation (2). Leider and Roth conducted a survey of public attitudes regarding markets for living and deceased donation. They found that a majority of respondents approved of either individual or government payment for either living or deceased donation (although there was considerably stronger support for government payment).
     "Segev and Gentry respond by noting that a survey of the membership of the American Society of Transplant Surgeons (ASTS) showed that only 20% were in favor of ‘cash
payments’ for donation (3). Segev and Gentry are correct. But what they did not note in their editorial,was that for deceased donation, the majority of ASTS respondents were
in favor of funeral expenses (73%), an income tax credit (65%) and about halfwere in favor of a donation to a charity selected by the donor’s family (51%) and reimbursement
of next-of-kin expenses (56%). For living donation, the majority supported payment of lost wages (76%), payment of health insurance premiums (72%) or an income tax credit
(64%) and 56% supported payment of life insurance premiums."...
     "It is a disservice to the debate and discussion to present only part of the ASTS survey results. There are other issues with Segev and Gentry’s Editorial. They suggest that doing these kinds of public opinion surveys are a waste of resources because: (a) physicians are against ‘sales’ and (b) to establish trials of ‘organ markets’ would require changing the law (1). However, using the same survey data that they quote (see above), (a) physicians are in favor of incentives (and before trials of incentives could be developed the law would need to be changed) and (b) legislators are certainly going to be more inclined to change the law if the public supports such a change. Finally, they conclude that the many recent advances in donation may solve the tremendous organ shortage problem,
making need for incentives moot. But the data says otherwise;  in spite of laparoscopic nephrectomy, use of ECDs, DCD, desensitization and paired exchange, there has been little or no increase in donation over the last few years and the wait list for a kidney transplant has continued to grow (4)."

Sally Satel, "The Physicians’ Voice Is Only One of Many," American Journal of Transplantation 2010; 10: 2558
    "...medical policy is a social activity, not a guild enterprise. The traditions and preferences of learned practitioners have a large role, to be sure, but they are not, nor
should they be, the sole determinants of clinical policies."
...
"As for physician opinion, Segev and Gentry relate only half of the story. True, a mere one-fifth of physician respondents to an ASTS poll endorsed cash payments to donors (1). Unmentioned, however, is the highly significant fact that 64% of respondents favored income tax credits to living donors (12% were neutral or undecided). This finding has critical policy relevance because it is regulated in-kind benefits, such as tax credits, not free market cash exchange, that have long been the basis for serious reform efforts in Congress and in state legislatures. Notably, the American Medical Association has endorsed proposals for pilot trials on three occasions between 1995 and 2008 (1995, 2003 and 2008) (3)."

Sunday, December 5, 2010

"Una persona altruista puede salvar muchas vidas"

"A selfless person can save many lives".

That's Mike Rees, the founder and guiding light of the Alliance for Paired Donation, being interviewed in El Pais about kidney exchange and non-simultaneous non-directed donor chains, which he pioneered.

(I even get a shout out: "La idea de la cadena me vino en diciembre de 2006, cuando conocí al profesor de Economía en la Universidad de Harvard Alvin Roth. Me hizo comprender que los emparejamientos no eran el modo más efectivo con los transplantes. Él es un experto en la llamada Teoría de Juegos, y me ayudó a desarrollar un modelo de cadena de trasplantes eficiente en que se deja de lado el incentivo económico.")

And here's the background story: Una cadena de trasplantes eterna, "An eternal chain of transplants"

HT: Flip Klijn and Jordi Masso

Cory Doctorow on copyright

Cory Doctorow in The Guardian: What do we want copyright to do?

"when we talk about copyright, we're not just talking about who pays how much to get access to which art, we're talking about a regulation that has the power to midwife, or strangle, enormous amounts of expressive speech."
...
"it's been more than a century since legal systems around the world took away songwriters' ability to control who performed their songs. This began with the first records, which were viewed as a form of theft by the composers of the day. You see, composers back then were in the sheet-music business: they used a copying device (the printing press) to generate a product that musicians could buy.

"When recording technology came along, musicians began to play the tunes on the sheet music they'd bought into microphones and release commercial recordings of their performances. The composers fumed that this was piracy of their music, but the performers said: "You sold us this sheet music – now you're telling us we're not allowed to play it? What did you think we were going to do with it?"

"The law's answer to this was a Solomonic divide-the-baby solution: performers were free to record any composition that had been published, but they had to pay a set rate for every recording they sold. This rate was paid to a collective rights society, and today, these societies thrive, collecting fees for all sorts of "performances" where musicians and composers get little or no say. For example, radio stations, shopping malls, and even hairdressers buy licences that allow them to play whatever music they can find. The music is sampled by more or less accurate means and dispersed to artists by more or less fair means."
...
"Rather than having the right to specify who may use your works, you merely get the right to get paid when the use takes place.

"Now, on hearing this, you might be thinking: "Good God, that's practically Stalinist! Why can't a poor creator have the right to choose who can use her works?" Well, the reason is that creators (and, notably, their industrial investors) are notoriously resistant to new media. The composers damned the record companies as pirates; the record labels damned the radio for its piracy; broadcasters vilified the cable companies for taking their signals; cable companies fought the VCR for its recording "theft." Big entertainment tried to kill FM radio, TV remote controls (which made it easy to switch away from adverts), jukeboxes, and so on, all the way back to the protestant reformation's fight over who got to read the Bible.

"Given that new media typically allow new creators to create new forms of material that is pleasing to new audiences, it's hard to justify giving the current lotto winners a veto over the next generation of disruptive technologies. Especially when the winners of today were the pirates of yesteryear. Turnabout is fair play."