Economist Finds Best Matches for Students and Schools

Al Roth and Marilda Sotomayor photographed with their 1990 book “Two-Sided Matching,” at the conference Roth and Sotomayor: Twenty Years After, held at Duke University in May, 2010. CREDIT: Marilda Sotomayor

This Behind the Scenes article was provided to LiveScience in partnership with the National Science Foundation.

While organ donation is not a category for which economics may first come to mind, the reality is that economic theory has been invaluable to making sure people who need organ transplants can get them. Al Roth is one of the founders and designers of the New England Program for Kidney Exchange, for incompatible patient-donor pairs, and has been deeply involved with the Alliance for Paired Donation, another kidney exchange network.  He is the Gund Professor of Economics and Business Administration in the Department of Economics at Harvard University, and in the Harvard Business School, and he and his students and colleagues are engaged in a new kind of economic engineering called market design, using tools from game theory, experimental and behavioral economics, and computer science.  Roth has also been involved in the reorganization of many of the markets for advanced medical fellowships and helped design the matching system used in New York City to match approximately ninety thousand students to high schools each year—for students entering high school since the fall of 2004—and a similar program for Boston Public Schools. He is also the chair of the American Economic Association's Ad Hoc Committee on the Job Market, which has designed a number of recent changes in the market for new Ph.D. economists. For more on Roth’s work, read an August 2010 profile in Forbes Magazine, and an NSF story about his work on kidney exchange. His web page of Game theory, Experimental economics, and Market Design contains many of his papers and other links, and he also blogs about market design. Below, Roth answers the ScienceLives 10 Questions.

Name: Al Roth
Age: 58
Institution: Harvard
Field of Study: Economics

What inspired you to choose this field of study?
My Ph.D. is in operations research, not economics, and I chose that field because I hoped to be able to find ways to help make the world work a little better. I studied game theory because I was interested in the parts of the world we make by interacting with each other. This drew me towards economics. I wanted to test the mathematical ideas I studied as a game theorist, and this led me to experimental economics, and to field studies of the “rules of the game” by which various markets operate. And, as we developed reliable knowledge about some of these things, that led naturally to market design, to see if we understood some kinds of markets well enough to fix them when they were broken, and construct them when they were absent.

What is the best piece of advice you ever received?
There’s no limit to what a person can accomplish if he isn’t worried about who gets the credit.

What was your first scientific experiment as a child?
I went to public school in NYC, and as I recall we had science fairs each year starting in grade school. The first projects I recall weren’t experiments; they were demonstrations, little bits of engineering. I remember that I built a carbon arc furnace out of boards, a flower pot, curtain rods and pieces of carbon from the core of a flashlight battery.

What is your favorite thing about being a researcher?
You can schedule your own mind. There are plenty of jobs in which a person has an opportunity to solve interesting problems, but a researcher, particularly an academic researcher, gets to choose which problems to work on.

What is the most important characteristic a researcher must demonstrate in order to be an effective researcher?
There are lots of different ways to be an effective researcher, maybe almost as many as there are effective researchers. You have to be able to find problems that are worth solving, and you have to be able to solve them. Each of those takes a combination of talents, and people have those in different proportions and deploy them in different ways.

What are the societal benefits of your research?
That’s an easy question for a market designer. Well-designed marketplaces create social benefits by allowing people to coordinate. Before we helped redesign the high school assignment process in New York City, about 30,000 children a year had to be assigned without regard to their families’ preferences; now that number is down to around 3,000. Before various medical specialty markets had effective centralized “match” clearinghouses, many doctors and hospitals dealt with each other via exploding offers that had to be quickly accepted or rejected sometimes years in advance of the beginning of employment, and now there is an orderly process that better accommodates the preferences of both sides of the market. Before kidney exchange, patients who had willing, live donors who turned out to be incompatible with them had to join the end of the long queue for deceased donors; now they can receive a live donor kidney from the incompatible donor of another patient, while their donor donates a kidney to that patient. This helps not only the patients receiving these kidneys, but also those on the queue for deceased donors, since the extra kidney donations remove people from that queue. (Check out the papers and news stories here.)

Who has had the most influence on your thinking as a researcher?
I think my older brother Ted first persuaded me that science was exciting, and I learned a lot from my Ph.D. advisor at Stanford, Bob Wilson. Over the long term, the group of people from whom I’ve learned the most are my students and post-docs and co-investigators; I’ve been very fortunate in who I’ve been able to work with.

What about your field or being a researcher do you think would surprise people the most?
Perhaps the most surprising thing about market design is the variety of things we get to do. We get to talk to people about their jobs and how they find them, or about the difficulties in allocating scarce resources like school places or kidneys for transplantation. We get to look at aggregate data to understand the big picture. We build mathematical models and prove theorems about them. We create small marketplaces in the laboratory and conduct experiments to see how peoples’ behavior changes as we vary the rules. We do computer simulations. We study successful markets, and market failures. We get to collaborate with and learn from not only other economists, but also the participants in the markets we study. We get to explain this work not only to our colleagues, but to policy makers and stakeholders in these markets. Sometimes we even get to suggest an improved way to organize a market or matching process or assignment method, and shepherd it through adoption and implementation.

If you could only rescue one thing from your burning office or lab, what would it be?
As often as not there’s a student or postdoc in my office. I’d rescue him or her.

Editor's Note: This research was supported by the National Science Foundation (NSF), the federal agency charged with funding basic research and education across all fields of science and engineering. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation. See the Behind the Scenes Archive.