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.

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What does it mean for Ukip if it loses in Stoke-on-Trent Central?

The party’s prospects are in question if it fails to win over the “Brexit capital” in Thursday's by-election.

“The Only Way Is Up!” blasted through a hall in Stoke-on-Trent Central on a damp Monday evening earlier this month. It was the end of a public Ukip meeting, in which Nigel Farage and his successor and by-election candidate Paul Nuttall made their rallying cries to an audience of around 650 supporters.

But even then, a fortnight ago, the note of triumph in the dance classic was tinged with uncertainty. “We’ve won the war, but we’ve yet to win the peace,” Farage admitted to the sympathetic crowd. And while this message is supposed to make Ukip’s fight relevant even in the context of Brexit-bound Britain, it betrays the party’s problem: the battle that was its raison d'être is over.

Failing fortunes

Since then, the party has had more to contend with. Its candidate in the Labour seat has been caught lying about having “close personal friends” killed at the Hillsborough disaster. This comes on top of a number of other false claims, and an investigation into whether he falsely registered his home address as being in the constituency.

After these scandals – and a campaign seemingly unable to turn out apathetic voters (which I covered a couple of weeks ago) – Ukip’s chances in the West Midlands seat look worse than expected.

Initially the main challenger to Labour, Ukip is now being predicted for third or even fourth place in the seat, behind a Tory party that essentially stood aside to give Nuttall room, and to focus on a concurrent by-election campaign in Copeland.

It’s in Labour’s interest for the campaign to continue looking like a close Labour-Ukip fight, in order to keep hold of tactical voters. But both the Conservative and Lib Dem campaigns are feeling more buoyant.

“We are relatively confident that Ukip are not going to win, and that is quite a change,” the Lib Dem campaign coordinator Ed Fordham told me. “That has actually relieved lots of voters of the emotional risk of letting in what they perceive to be an unpleasant, far-right option . . . and voting for who they would like to represent them.”

One local activist chirped: “It will hopefully be a terrible result for Ukip.”

So what will it mean for Ukip if it loses?

Great expectations

Ukip has a lot riding on this seat. Farage called the by-election “absolutely fundamental” to Ukip’s future. Its new leader, Nuttall, took the risk of running as the party’s candidate there – riding his reputation on the by-election.

This created a lot of hype about Ukip’s chances, which the party has privately been trying to play down ever since. Even before the scandal surrounding Nuttall, he was emphasising that the seat had only been Ukip’s 72nd target, and told me he had taken a gamble by running for it. “The way it’s being written up as if this is the one – it wasn’t,” he insisted.

But Stoke-on-Trent, where 69 per cent voted Leave, has been labelled the “Brexit capital”. According to political scientist Rob Ford, the author of Revolt on the Right who has been studying Labour’s most Ukip-vulnerable seats: “It should be a pretty favourable seat for them, pretty favourable demographics, pretty favourable [negative] attitudes about the EU, very high Brexit vote there and so on.”

In other words, if Ukip can’t win here, against a weak Labour party, where can it win?

Struggle for seats

Brexit is central to Ukip’s by-election campaign. The party has highlighted Labour’s splits over Europe, pointed out the Labour candidate Gareth Snell’s Remainer credentials, and warned that the government needs to be held to account when negotiating Britain’s exit.

But Ford believes this rhetoric is unlikely to work, since the Tories are already pursuing a “hard” Brexit focused on immigration control. “A difficulty for Paul Nuttall and Ukip is that people are going to say: why would we vote for you when we’re getting what we want from the government? What’s the point right now?” he said. “I can have all the Brexity stuff, all the immigration control stuff, but with none of the incompetence and serial lying about Hillsborough – I think I’ll take that!”

So if rerunning the EU referendum doesn’t work, even in such a Brexit-heavy seat, this means trouble for Ukip elsewhere in the country. A Ukip councillor in a top Ukip target seat with similar demographics to Stoke believes it’s “crisis time” for the party.

“It is very sad to say, but Ukip has lost its way,” they told me. “It’s still a strong party, but after losing Nigel, it’s lost a little of its oomph. The new gentleman [Nuttall] has been silly with the comments he’s made. That’s a big worry in some regards. You need to be a people person. It’s a serious situation at the minute.”

If Ukip can’t prove it can win parliamentary seats – even in favourable by-elections – then it will be difficult to prove its authority as a political party come the general election.

Leadership lament

Should Nuttall lose, Ukip’s leadership will come into question. Again. During a tumultuous time late last year, when the favourite Steven Woolfe left the party after a physical altercation, and Diane James quit the leadership after 18 days, commentators asked if Ukip was anything without Farage.

When Nuttall eventually took over, the same voices warned of his threat to Labour – citing his northern and working-class roots. It’s likely this narrative will change, and Farage’s golden touch pondered again, if Nuttall fails to win.

But rather than panic about its national leader, Ukip must look carefully at those who commit to the party in local campaigns. On the ground in Stoke, running Nuttall as a candidate instead of a local Ukipper is seen as a mistake.

“I don’t know why they did that,” one local activist for an opposing party commented. “If they’d run Mick Harold, they would’ve won. He’s a Stokie.”

Harold, the deputy chair of Staffordshire County Committee, and chair of Ukip’s Stoke-on-Trent Central/North branch, won 22.7 per cent of the vote for Ukip in the constituency in 2015. He insists that he stands by his decision to step aside for Nuttall, but does highlight that Ukip should increase its vote share.

“If we’re increasing our percentage share of the vote, we’re still moving forward and that’s how we’ve got to look at it,” he told me. “I got 22.7 per cent in 2015. I would think this time we’re going to certainly get somewhere around the 30 per cent mark.”

Would it have been more likely to achieve this with Harold as candidate? “Whatever happens, happens, we’ve just got to move forward,” he replied. “If you’ve made a mistake, you move on from it.”

I have heard similar misgivings from local activists in other parts of the country – people who have achieved impressive results in local elections and the general election, but haven’t had much thanks from the national party. “We need to get professionalised now,” one such campaigner said. “Because we’ve got grassroots people who are not career politicians [doing all the hard work].” They say their local party is fed up with leadership being dictated by “personal grudges” at the top of the party.

***

As I’ve written before, I don’t think this is the end of Ukip. Once Brexit starts to bite, and it’s clear immigrants are still needed to fill jobs, there will be resentment enough to make space for them again. But losing Stoke will highlight the challenges – of purpose, leadership and local organisation – that the party will need to overcome for its next stand.

Anoosh Chakelian is senior writer at the New Statesman.