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.

Getty
Show Hide image

If there’s no booze or naked women, what’s the point of being a footballer?

Peter Crouch came out with one of the wittiest football lines. When asked what he thought he would have been but for football, he replied: “A virgin.”

At a professional league ground near you, the following conversation will be taking place. After an excellent morning training session, in which the players all worked hard, and didn’t wind up the assistant coach they all hate, or cut the crotch out of the new trousers belonging to the reserve goalie, the captain or some senior player will go into the manager’s office.

“Hi, gaffer. Just thought I’d let you know that we’ve booked the Salvation Hall. They’ll leave the table-tennis tables in place, so we’ll probably have a few games, as it’s the players’ Christmas party, OK?”

“FECKING CHRISTMAS PARTY!? I TOLD YOU NO CHRISTMAS PARTIES THIS YEAR. NOT AFTER LAST YEAR. GERROUT . . .”

So the captain has to cancel the booking – which was actually at the Salvation Go Go Gentlemen’s Club on the high street, plus the Saucy Sporty Strippers, who specialise in naked table tennis.

One of the attractions for youths, when they dream of being a footballer or a pop star, is not just imagining themselves number one in the Prem or number one in the hit parade, but all the girls who’ll be clambering for them. Young, thrusting politicians have similar fantasies. Alas, it doesn’t always work out.

Today, we have all these foreign managers and foreign players coming here, not pinching our women (they’re too busy for that), but bringing foreign customs about diet and drink and no sex at half-time. Rotters, ruining the simple pleasures of our brave British lads which they’ve enjoyed for over a century.

The tabloids recently went all pious when poor old Wayne Rooney was seen standing around drinking till the early hours at the England team hotel after their win over Scotland. He’d apparently been invited to a wedding that happened to be going on there. What I can’t understand is: why join a wedding party for total strangers? Nothing more boring than someone else’s wedding. Why didn’t he stay in the bar and get smashed?

Even odder was the behaviour of two other England stars, Adam Lallana and Jordan Henderson. They made a 220-mile round trip from their hotel in Hertfordshire to visit a strip club, For Your Eyes Only, in Bournemouth. Bournemouth! Don’t they have naked women in Herts? I thought one of the points of having all these millions – and a vast office staff employed by your agent – is that anything you want gets fixed for you. Why couldn’t dancing girls have been shuttled into another hotel down the road? Or even to the lads’ own hotel, dressed as French maids?

In the years when I travelled with the Spurs team, it was quite common in provincial towns, after a Saturday game, for players to pick up girls at a local club and share them out.

Like top pop stars, top clubs have fixers who can sort out most problems, and pleasures, as well as smart solicitors and willing police superintendents to clear up the mess afterwards.

The England players had a night off, so they weren’t breaking any rules, even though they were going to play Spain 48 hours later. It sounds like off-the-cuff, spontaneous, home-made fun. In Wayne’s case, he probably thought he was doing good, being approachable, as England captain.

Quite why the other two went to Bournemouth was eventually revealed by one of the tabloids. It is Lallana’s home town. He obviously said to Jordan Henderson, “Hey Hendo, I know a cool club. They always look after me. Quick, jump into my Bentley . . .”

They spent only two hours at the club. Henderson drank water. Lallana had a beer. Don’t call that much of a night out.

In the days of Jimmy Greaves, Tony Adams, Roy Keane, or Gazza in his pomp, they’d have been paralytic. It was common for players to arrive for training still drunk, not having been to bed.

Peter Crouch, the former England player, 6ft 7in, now on the fringes at Stoke, came out with one of the wittiest football lines. When asked what he thought he would have been but for football, he replied: “A virgin.”

Hunter Davies is a journalist, broadcaster and profilic author perhaps best known for writing about the Beatles. He is an ardent Tottenham fan and writes a regular column on football for the New Statesman.

This article first appeared in the 01 December 2016 issue of the New Statesman, Age of outrage