When Buyers & Sellers Choose Each Other
A patient with kidney disease goes to his doctor with good news: He found a donor who would be willing to give up one of her kidneys. A series of tests, however, shows that the donor-recipient match is incompatible. This scenario occurred at Rhode Island hospital with two pairs of donors and recipients. Then the Rhode Island surgeons realized that the donor of one pair was compatible with the recipient of the other pair, and vice-versa. With the permission of both donors and both patients, the surgeons did a kidney “exchange.”
Those operations planted the seed of what would become the New England Program for Kidney Exchange (NEPKE), a “matching market” for kidneys based on algorithms developed by Nobel Prize-winning economist Alvin E. Roth. (As opposed to commodity markets, matching markets allow buyers and/or sellers a choice in what they buy or whom they sell to.)
In his new book, Who Gets What — and Why, an engaging exploration of the different types and different roles of matching markets that underpin how our world operates, Roth devotes a full chapter to the creation and expansion of NEPKE — a market that does not involve money since the sale of kidneys is illegal and has been expanding thanks to the continued evolution of its rules.
Rules Are Necessary for Markets
Rules are at the heart of market design, the discipline for which Roth is perhaps the world’s most pre-eminent expert. Politicians talk of free markets as if no rules are necessary, as if self-interest and self-control will ensure the efficiency of markets. But as Roth shows through his many examples, rules are necessary because markets only work under the right conditions. For example, markets need to be thick — there must be a sufficient number of buyers and sellers all active at the same time for the market to work. The kidney exchange works because a sufficiently large database of donors and patients was created.
At the same time, markets cannot be too congested. Buyers need to be able to find what they want in the market in a timely manner. Travelers using Airbnb, which created a market of rooms in personal homes acting as hotel rooms, were hampered by the response time from hosts using personal computers. Smartphones (hosts no longer had to wait to check their computers at home at night) relieved the congestion. Markets also need to be safe: Both buyers and sellers must be assured that they will not be cheated. One of the challenges of Uber was convincing travelers that the car would show up and convincing Uber drivers that passengers would wait. Markets that are not thick, uncongested or safe will unravel and no longer fulfill their functions.
In Who Gets What — and Why, Roth’s clear jargon-free writing helps readers navigate the nuances and implications of market design. Roth’s wit and the variety of case studies he describes in detail also help. For example, Roth describes how the market for gastroenterology fellowships (the educational step after internal-medicine residency) “unraveled.” The section is titled, “Finding the Guts to Wait.”
Packed with fascinating stories, from the history behind the nickname Oklahoma Sooners to the role that repugnance plays in market design, Who Gets What –– and Why is at once supremely insightful and entertaining — a rare combination for an economics text.