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.

Photo: Getty Images
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Bomb Isil? That's exactly what they want

The government appears not to answer the nature of its enemy, warns Maria Norris.

As MPs are set to vote on further airstrikes in Syria, it is difficult to shake off the feeling that the government does not fully appreciate the complexity of the problem Isil poses. Just a cursory glance at its magazine, the pronouncements of its leaders and its ideology reveals that Isil is desperate for Western bombs to fall out of the sky. As Martin Chulov argues, Isil is fighting a war it believes was preordained since the early days of Islam. Isil’s obsession with the city of Dabiq, in Northern Syria, stems from a hadith which prophesises that the ‘Crusader’ army will land in the city as a precursor to a final battle where Islam will emerge victorious. Dabiq is also the name of its magazine, which starts every issue with the same quote: "The spark has been lit here in Iraq, and its heat will continue to intensify -- by Allah's permission -- until it burns the crusader armies in Dabiq". Isil wants a war with the West. If we don’t negotiate with terrorists, then we also should not give them what they want.

Further, bombs are indiscriminate and will inevitably lead to the suffering of those trapped in Isil territories. Isil is counting on this suffering to swell their ranks. Civilian suffering from airstrikes only underline the narrative that the West is at war with Islam, which plays directly into Isil’s hands. And despite misleading headlines and the genuine government concern with individuals fleeing to Syria, Isis is supremely unpopular. It is no wonder that its magazine is filled with glossy adds begging people to move to its territories.  You cannot be a state without people. Terrorist attacks such as Paris thus have a two-pronged purpose: they provoke the West to respond with its military, and they act as a recruitment drive. The fact that fake Syrian passports were found around the sites of the Paris attacks is no coincidence as Isil are both seeking to stem the flow of refugees from its territories and hoping to provoke an Islamophobic backlash. They hope that, as more Muslims feel alienated in the West, more will join them, not just as fighters, but as the doctors, nurses and teachers it desperately needs.

In addition to this, airstrikes overlook the fact that Isil is a result of what Fawaz Gerges calls a severe, organic institutional crisis in the Middle East. In a lecture at the London School of Economics earlier this year, Gerges pointed out the dysfunction created when a region that is incredibly resource rich also is also deeply undemocratic, riddled with corruption, food insecurity, unemployment and poverty. This forms an institutional vacuum that is filled by non-state actors as the population does not trust its political structures. Further, the civil war in Syria is also the site of the toxic soup of Middle Eastern state dysfunction. Iran supports Assad, Saudi Arabia and the Gulf countries, fund anti-Shia groups in Syria. Throw in the Kurdish conflict, Turkey’s ambiguous position and Russian bombs, it is difficult to see how airstrikes will solve anything.

Finally, it is crucial that Isil is seen as a direct result of the Iraq war. The American-led invasion destroyed the institutions, giving the Shia majority power almost overnight, creating deep dissatisfaction in the Sunni regions of Iraq. On top of this thousands of foreign fighters flooded Iraq to fight the invaders, attracting disenfranchised and angry Sunnis. The result is that since 2003, Iraq has been embroiled in a sectarian civil war.  It is in civil war, inherently connected to the Iraq War, that you find the roots of Isil. As even the Prime Minister concedes that ground troops are necessary, albeit it regional ground troops with its own set of problems, it is important to consider what further monster can arise from the ashes of another ill-thought out military intervention in the Middle East.
We have had decades of military intervention in the Middle East with disastrous consequences. Airstrikes represent business as usual, when what we actually need is a radically new approach. Who is funding Isil? Who is buying its oil? How to curb Isil’s recruitment drives? What can be done about the refugees? How to end the conflict in Syria? What happens to Assad? These are questions hopefully being addressed in talks recently held in Vienna with Russian, Ira, the USA, France, Syria’s neighbours and the Gulf states. Airstrikes do not answer any of these questions. What airstrikes do is give Isil exactly what it is asking for. Surely this is reason enough not to bomb Syria. 

Maria W. Norris is a PhD candidate and a teacher at the London School of Economics and Political Science. Her PhD is on the UK counter-terrorism strategy since 9/11 and its relationship with identity. She tweets as @MariaWNorris.