Trading kidneys, repugnant markets and stable marriages win the Nobel Prize in Economics

Roth and Shapley charted a course for economists to go beyond simply arguing for markets in everything.

The 2012 Nobel Prize in Economics - technically the Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel, but nobody cares - has been awarded to two American Economists, Alvin Roth and Lloyd Shapley "for the theory of stable allocations and the practice of market design". The Nobel Committee explains what that means:

This year's Prize concerns a central economic problem: how to match different agents as well as possible. For example, students have to be matched with schools, and donors of human organs with patients in need of a transplant. How can such matching be accomplished as efficiently as possible? What methods are beneficial to what groups? The prize rewards two scholars who have answered these questions on a journey from abstract theory on stable allocations to practical design of market institutions.

Lloyd Shapley used so-called cooperative game theory to study and compare different matching methods. A key issue is to ensure that a matching is stable in the sense that two agents cannot be found who would prefer each other over their current counterparts. Shapley and his colleagues derived specific methods – in particular, the so-called Gale-Shapley algorithm – that always ensure a stable matching. These methods also limit agents' motives for manipulating the matching process. Shapley was able to show how the specific design of a method may systematically benefit one or the other side of the market.

Alvin Roth recognized that Shapley's theoretical results could clarify the functioning of important markets in practice. In a series of empirical studies, Roth and his colleagues demonstrated that stability is the key to understanding the success of particular market institutions. Roth was later able to substantiate this conclusion in systematic laboratory experiments. He also helped redesign existing institutions for matching new doctors with hospitals, students with schools, and organ donors with patients. These reforms are all based on the Gale-Shapley algorithm, along with modifications that take into account specific circumstances and ethical restrictions, such as the preclusion of side payments.

Even though these two researchers worked independently of one another, the combination of Shapley's basic theory and Roth's empirical investigations, experiments and practical design has generated a flourishing field of research and improved the performance of many markets. This year's prize is awarded for an outstanding example of economic engineering.

The committee have yet again reaffirmed the old adage that the most important thing to do when trying for a nobel prize is to live long enough that your achievements are recognised. The Gale-Shapley algorithm, for instance, was devised in 1962, when Lloyd Shapley was 34. It concerns a maths problem known as the stable marriage problem: if you have an even number of men and women, can you always come up with a set of marriages where there are no two people of opposite sex who would both rather have each other than their current partners? (1960s maths problems: usually heteronormative.) If you can, then the marriage is "stable".

The Gale-Shapley algorithm is a way of always ensuring stable matches; and much of Shapley's work covers the same areas, straddling the boundaries between economics, mathematics, and computer science.

Roth is the younger of the two winners, and works in a far more empirical sphere. As the committee points out, although the two men never actually collaberated, Roth took Shapley's theoretical work and applied it to actually existing markets. For instance, Roth used the Gale-Shapley agorithm to ease the kidney shortage in the US. David Wessel explains (£):

As of noon yesterday, 58,470 people in the U.S. were waiting for a kidney transplant. Most won't get one this year. There aren't enough donated kidneys to go around. Surgeons transplanted just 15,129 kidneys last year. Now a band of transplant surgeons and economists are trying to fix that by creating a moneyless market for exchanging kidneys. Most transplanted kidneys come from a person who has died, a supply that grows slowly because of ignorance about the need for donations or grieving relatives' reluctance. But a kidney taken from a live donor works better, and almost everyone has a spare. As techniques improve for removing healthy kidneys and for suppressing the body's tendency to reject a transplant, doctors increasingly turn to kidneys from living donors, usually relatives. Last year, 43% of kidneys transplanted in the U.S. came from living donors, up from 28% a decade ago. But a biological barrier often blocks a transplant from a relative. In about a third of all would-be pairs, blood types are incompatible. In others, the sick person has antibodies that can initiate a rejection of the donated organ. It's heartbreaking "to have the treasure of the live donor and then have that not go forward because of a biological obstacle," says Massachusetts General Hospital transplant surgeon Francis DelMonico.

Occasionally, transplant centers spot a way out: One New England father with blood type A couldn't donate a kidney to his daughter with blood type B. So he gave a kidney to a teenager with blood type A, and the teenager's sister gave a kidney for the man's daughter. New England's transplant centers have done six such exchanges. Baltimore's Johns Hopkins University has done seven.

The crucial thing about Roth's work, from an economic point of view, is that it involves finding stable allocations using market-like situations without involving money. The kidney swaps in the New England situation are market-like, trading kidneys for kidneys in a way that makes all parties better-off, but they don't actually require kidneys to be bought and sold.

We can see the importance of this by looking at another paper of Roth's, not cited by the committee, on repugnance in markets (pdf). Roth demonstrates that some markets are limited because the very existance of a market in some goods is considered repugnant. He argues, for instance, that the trade in horse meat being banned in California is not done through fears that eating horse meat is unsafe; nor is it done for animal welfare reasons, since it is still legal to farm and kill horses. But banned it is, and Roth argues that the natural response of economists to situations of this type - to argue for freer markets - is wrong, since it ignores the very strong feelings involved in the situation. Instead:

Being aware of the sources of repugnance can only help make such discussions more productive, not least because it can help separate the issues that are fundamentally empirical—like the degree of crowding out of altruistic donations that might result from different incentive schemes compared to how much new supply might be produced—from areas of disagreement that are not primarily empirical.

Hopefully his new Nobel Prize should give that argument greater weight in the years ahead.

A patient receives a kidney in Johns Hopkins university in Baltimore. Photograph: Getty Images

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

Show Hide image

Meet Anne Marie Waters - the Ukip politician too extreme for Nigel Farage

In January 2016, Waters launched Pegida UK with former EDL frontman Steven Yaxley-Lennon (aka Tommy Robinson). 

There are few people in British political life who can be attacked from the left by Nigel Farage. Yet that is where Anne Marie Waters has found herself. And by the end of September she could well be the new leader of Ukip, a party almost synonymous with its beer-swilling, chain-smoking former leader.

Waters’s political journey is a curious one. She started out on the political left, but like Oswald Mosley before her, has since veered dramatically to the right. That, however, is where the similarities end. Waters is Irish, agnostic, a lesbian and a self-proclaimed feminist.

But it is her politics – rather than who she is – that have caused a stir among Ukip’s old guard. Former leader Paul Nuttall has said that her views make him “uncomfortable” while Farage has claimed Ukip is “finished” if, under her leadership, it becomes an anti-Islam party.

In her rhetoric, Waters echoes groups such as the English Defence League (EDL) and Britain First. She has called Islam “evil” and her leadership manifesto claims that the religion has turned Britain into a “fearful and censorious society”. Waters wants the banning of the burqa, the closure of all sharia councils and a temporary freeze on all immigration.

She started life in Dublin before moving to Germany in her teens to work as an au pair. Waters also lived in the Netherlands before returning to Britain to study journalism at Nottingham Trent University, graduating in 2003. She subsequently gained a second degree in law. It was then, she says, that she first learnt about Islam, which she claims treats women “like absolute dirt”. Now 39, Waters is a full-time campaigner who lives in Essex with her two dogs and her partner who is an accountant.

Waters’s first spell of serious activism was with the campaign group One Law for All, a secularist organisation fronted by the Iranian feminist and human rights activist Maryam Namazie. Waters resigned in November 2013 after four years with the organisation. According to Namazie, Waters left due to political disagreements over whether the group should collaborate with members of far-right groups.

In April 2014, Waters founded Sharia Watch UK and, in January 2016, she launched Pegida UK with former EDL frontman Steven Yaxley-Lennon (aka Tommy Robinson). The group was established as a British chapter of the German-based organisation and was set up to counter what it called the “Islamisation of our countries”. By the summer of 2016, it had petered out.

Waters twice stood unsuccessfully to become a Labour parliamentary candidate. Today, she says she could not back Labour due to its “betrayal of women” and “betrayal of the country” over Islam. After joining Ukip in 2014, she first ran for political office in the Lambeth council election, where she finished in ninth place. At the 2015 general election, Waters stood as the party’s candidate in Lewisham East, finishing third with 9.1 per cent of the vote. She was chosen to stand again in the 2016 London Assembly elections but was deselected after her role in Pegida UK became public. Waters was also prevented from standing in Lewisham East at the 2017 general election after Ukip’s then-leader Nuttall publicly intervened.

The current favourite of the 11 candidates standing to succeed Nuttall is deputy leader Peter Whittle, with Waters in second. Some had hoped the party’s top brass would ban her from standing but last week its national executive approved her campaign.

Due to an expected low turnout, the leadership contest is unpredictable. Last November, Nuttall was elected with just 9,622 votes. More than 1,000 new members reportedly joined Ukip in a two-week period earlier this year, prompting fears of far-right entryism.

Mike Hookem MEP has resigned as Ukip’s deputy whip over Waters’ candidacy, saying he would not “turn a blind eye” to extremism. By contrast, chief whip, MEP Stuart Agnew, is a supporter and has likened her to Joan of Arc. Waters is also working closely on her campaign with Jack Buckby, a former BNP activist and one of the few candidates to run against Labour in the by-election for Jo Cox’s former seat of Batley and Spen. Robinson is another backer.

Peculiarly for someone running to be the leader of a party, Waters does not appear to relish public attention. “I’m not a limelight person,” she recently told the Times. “I don’t like being phoned all the time.”

The journalist Jamie Bartlett, who was invited to the initial launch of Pegida UK in Luton in 2015, said of Waters: “She failed to remember the date of the demo. Her head lolled, her words were slurred, and she appeared to almost fall asleep while Tommy [Robinson] was speaking. After 10 minutes it all ground to an uneasy halt.”

In an age when authenticity is everything, it would be a mistake to underestimate yet another unconventional politician. But perhaps British Muslims shouldn’t panic about Anne Marie Waters just yet.

James Bloodworth is editor of Left Foot Forward

This article first appeared in the 17 August 2017 issue of the New Statesman, Trump goes nuclear