Make Me a Match (Update)

Last month, the federal government announced plans to modernize the U.S. organ-donation system. They want to speed up the process by which organ-transplant patients are matched with donated organs, and they also want to reduce racial inequities in the system. When we saw this news, we decided to go into our archive and put together the episode you’re about to hear. It’s a mashup of a 2015 episode, No. 209, called “Make Me a Match,” and a portion of a 2016 episode, No. 237, which includes a personal story from a listener who was inspired by that earlier episode to make a remarkable decision. All the relevant facts and figures have been updated. As always, thanks for listening.

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Al ROTH: I’m Al Roth and I’m a professor of economics at Stanford. 

For many years, Roth had taught economics at Harvard. But he and his wife, who’s a human-factors engineer, had relocated.

ROTH: We had just moved into our new apartment. We had moved to Stanford in September of 2012.

Shortly thereafter, on October 15th, something memorable happened.

ROTH: My wife woke up around three in the morning and said, “The phone’s ringing.” And I woke up and it wasn’t ringing anymore. We had one phone at that point and it was in her office, which was downstairs. So I said, “It’s not ringing,” and went back to sleep. And she went down and got the phone and it started ringing again. It turns out it’s a good thing they call you back, they don’t go down their list. And it was the Nobel Committee. 

Roth, half-asleep, was informed that he, along with Lloyd Shapley, had won the Bank of Sweden Prize in Economic Sciences in Memory of Alfred Nobel — also known as the Nobel Prize in Economics.

Stephen DUBNER: Did you think you had a chance? 

ROTH: It’s hard to answer that humbly. So I knew that I was on the big list of people who, if I won a Nobel Prize, it wouldn’t cause the Nobel committee to be embarrassed. The newspapers the next day would not say, “Craziness in Stockholm.” But there are many, many people in that category. So indeed, we had — we were asleep. We were not waiting for a call. And it’s an interesting call because one of the things they’re concerned about — they have a lot of experience with this — is convincing you that it’s not a prank. So the person who first spoke to me said, you know, “Congratulations. You’ve won the Nobel Prize.” And then he said, “And I’m here with six of my colleagues and two of them know you and they’re going to talk to you now.”

DUBNER: To persuade you that this is for real. 

ROTH: Right. 

DUBNER: Either that, or a very elaborate prank. 

ROTH: Exactly. But they call you up and say, “So in half an hour this is going to happen. Get ready.” And, you know, I took a shower and got dressed, which was a good thing, because there wasn’t the opportunity to do that again all day.

DUBNER: And what was the rest of the day like then?

ROTH: Well, so at five minutes to, someone calls you back and again, they’re still I guess concerned that you shouldn’t appear confused on the phone. So what she said was, “Point your browser to the Nobel site and you will see your name being announced and then we will come on the line and have a press conference by telephone.” So by the time that happened, I was ready and then the Stanford press office fortunately descended on our house at 4:00 am and started fielding calls from journalists. You know, when they’d say, “Professor Roth is ready now. Are you ready?” And I’d get the phone and I’d get five questions from someone and I would speak to many, many people. And apparently I mostly answered them very, very seriously, but I told a joke or two that I hadn’t intended to tell. But people would say to me, “Oh, I heard you on N.P.R. You said something odd.” And then there was a press conference, and then at 11:00 I had a class. So people seemed a little surprised, but that’s how we ended the press conference. This was a surprise and it was a Monday, and I teach on Mondays.

DUBNER: Word had travelled to your students by then, I assume?

ROTH: It had. There was champagne in the classroom.

So what kind of work did Al Roth do to land a Nobel Prize in Economics? Well, it’s not the kind of work that typically wins a Nobel. He has helped people who need a kidney transplant find a donor. He’s helped new doctors find their first jobs. He’s helped high-school students in New York City find the right high school — even though Roth himself, who grew up in New York City, dropped out of high school.

ROTH: I was a poor ungrateful student who didn’t appreciate what my teachers were trying to do for me. You should tell all your listeners they should complete high school. 

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Back in 2015, I visited Palo Alto, California, home to Stanford University — and a few other things — to talk with Al Roth. He was, as you’ve heard, a high-school dropout. But don’t worry, he did go on to college — many, many years of college. Not finishing high school isn’t the only odd thing about Al Roth as a Nobel laureate. Consider this: even though he won the prize in economics, and even though he’s a professor of economics, he is not technically an economist.

ROTH: I mean, my degrees are in engineering. And I wrote a paper once, a manifesto of market design called “The Economist as Engineer,” so I think of myself as something like an engineer. I’d like to be an engineer.

“A manifesto of market design,” Roth calls it. The Nobel Committee’s citation noted his “theory of stable allocations and the practice of market design.” So what is market design, and why can it win you a Nobel Prize?

ROTH: Market design is an ancient human activity. When you look at a distribution of stone tools around the Middle East and Europe, you find that long before the invention of agriculture, stone tools were moving thousands of miles from where they were quarried and made. And that’s a sign that there were markets for stone tools. There were ways to meet and trade things and we don’t really know much about those markets. But the stone tools, which are very durable, are evidence that markets are older than agriculture. But the Stone Age men who traded those stone tools and weapons had to make markets somehow. They had to make them safe. They had to feel confident that they could bring the things that they would trade for those stone tools and not be robbed by guys with stone axes who would take their stuff. And that’s been a big part of market design for a long time is making markets safe. Today we think about fraud and identity theft and securing your credit card. But there was a time when kings thought about securing the roads against highwaymen so you wouldn’t be waylaid on your way to and from the market. So if I were the king of England and I wanted to have markets in England, I had to make sure that the roads were safe to get to the markets.

Al Roth has written a book — a really wonderful book, I should say — called Who Gets What — and Why: The New Economics of Matchmaking and Market Design. If market design is, as Roth says, an “ancient human activity,” why does someone like him need to get involved? After all, we’re told that markets generally organize themselves, right? There are sellers and buyers, supply meeting demand, with price being the glue that holds it all together. In this regard, the invention of money was a big breakthrough.

ROTH: Barter is very hard because you need a double coincidence of wants. You need to find someone who has what you want and who wants what you have. 

DUBNER: Right, you happen to have salt, I happen to have wool and we each want what the other wants, or we find a third party.

ROTH: Right. Well, so finding the third party starts getting you involved in other things. And, of course, money is a great market-design invention for helping you find third parties because you can sell what you have for money and then go look for what you want. 

But there are some transactions — entire realms of transactions, really — where money cannot do what it does in a typical market. Where, for whatever reason, supply is not allowed to naturally meet demand with price as the arbiter. And that’s where someone like Al Roth comes in handy. The economist as engineer. Because these atypical markets have to be set up differently, they have to be helped along. This is sometimes called a “matching market.”

ROTH: Matching markets are markets where money, prices don’t do all the work. And some of the markets I’ve studied, we don’t let prices do any of the work. And I like to think of matching markets as markets where you can’t just choose what you want even if you can afford it — you also have to be chosen. So job markets are like that, getting into college is like that. Those things cost money, but money doesn’t decide who gets into Stanford. Stanford doesn’t raise the tuition until supply equals demand and just enough freshmen want to come to fill the seats. Stanford is expensive, but it’s cheap enough that a lot of people would like to come to Stanford, and so Stanford has this whole other set of market institutions, applications and admissions. And you can’t just come to Stanford, you have to be admitted. 

Or think about this problem, which Al Roth has worked on directly: what’s the best way for hospitals to hire newly minted doctors, and for those doctors to find the most appropriate hospital for them to work in? The current system is called the National Resident Matching Program:

ROTH: So I got involved in helping it during a crisis in the 1990s. But you have to go back to the 1900s to understand how doctors get jobs. And the 1900s is around the time when the medical degrees as we know them, the M.D. degree, became the dominant medical degree. In about 1900, that’s when internships began. So instead of graduating from medical school and immediately beginning to “practice medicine,” as we say —

DUBNER: A word that’s always bothered me.

ROTH: Yes. 

DUBNER: You should be good at it by now.

ROTH: The first job — the standard first job for medical graduates became what was called an internship, and is today called a residency. And that’s a job where you work at a hospital and you take care of patients under the supervision of a more experienced attending physician. And it’s a giant part of the professional education of doctors. So it’s very important to doctors where they get their internship and residency. And it’s very important to hospitals because the interns and residents are a very important part of the labor force of a hospital.

As Roth tells it, there was an arms race between hospitals for the best future doctors. They began grabbing medical students earlier and earlier — sometimes two years before graduation.

ROTH: And when you try hiring people two years in advance, it’s hard to tell who the good doctors will be. It’s also hard for the doctors to tell what kind of jobs they want. 

So the medical schools intervened. In 1952, they created the National Resident Matching Program.

ROTH: They developed a marketplace that has a form that has survived ‘til today, although my colleagues and I have helped modify it since then. And what that form was — you go on interviews and you find out the salary and the working conditions of the various jobs that you might be offered and then, instead of working the phones and maybe getting an offer that says you have to take it — yes or no right now on the phone — what you do is you consider in advance which jobs you would like and you submit a rank order preference. This would be my first choice of the jobs I’ve interviewed at. Here’s my second choice. Here’s my third. And the jobs do the same thing, the hospital residency programs do the same thing. And then a match is made in a centralized clearinghouse. 

By the 1990s, this system was showing strain. Some people thought the hospitals had too much leverage over the residents. Also: by now, there were a lot more female medical students, some of whom had a significant other who was also a medical student — and such a couple typically wanted to get a residency in the same hospital, or at least the same region. But the matching program couldn’t handle that kind of request. So those candidates might opt out. In 1995, Al Roth was asked to help write an algorithm that could fix these problems. The algorithm worked well, and it now matches about 40,000 applicants each year.

DUBNER: It sounds as though this works pretty well according to most people involved, yes? Most people involved in this scenario are pretty happy with how it works, correct?

ROTH: Well, labor markets are stressful for everyone. So I think you are overstating how happy people are with the labor market. But I think it works pretty well.

DUBNER: I mean in the medical residency matching particularly. Or at least an improvement over what was before?

ROTH: It’s a vast improvement.

DUBNER: But here’s my question for you really, is this — broader labor markets. If we consider the medical residency matching program relatively successful to what preceded it, at least, why is it not used more widely in the labor markets?

ROTH: Well, the medical market is an easier one to coordinate than many markets because just about everyone becomes available at the same time when they graduate from medical school and they all start their jobs therefore about the same time in July. So it’s a market that can easily move people all at the same time. Whereas many markets, think about the market for journalists, they might be hired at different moments and jobs might become available and need to be filled and not be able to wait for you to consider many jobs.

DUBNER: Yeah, but you and your colleagues are pretty brilliant and you have mathematical backgrounds. I would think you could deal with rolling admissions, is that right? For all the talk about how modern labor markets have so many mismatches in them — so many people doing jobs that they don’t really want to be doing, so many corporations with all these theoretically qualified people out there not being able to find the people to fill them without going through a lot of trouble. I mean, hiring practice has become more and more complicated, it seems, as one way to address the matching problem. But it seems as though your complicated mathematical foundation might provide, ironically, a simpler way to address that problem.

ROTH: So I’m not sure that’s true. Again, one of the special things about residency positions is, although they’re very different at different places, they’re sort of similar to each other. If you’re thinking about should you be a journalist or an airplane pilot or a chef, you are dealing with very different jobs with very different employers. And one of the things that we do in the medical match is we make all the jobs available at the same time that allows you to consider them, to have preferences over them. That’s hard to do if you’re thinking about being a chef or an auto mechanic.

DUBNER: Sure. I’m curious to know, what’s a market or scenario that you’ve looked at before that you thought, “Boy, I would love to help fix that one,” but either haven’t had a shot or maybe tried and failed?

ROTH: Well, the markets for new lawyers might fall into that category and certainly the fanciest job that top graduates of elite law schools get is a lot like a medical residency. It’s a clerkship with an appellate judge. That market is presently in the kind of situation that the doctor market was around 1940, where jobs are being contracted far before law school graduation. And probably a dozen times in the last 30 years, the lawyers have tried to fix this with things like setting dates before which you shouldn’t hire and things like that, but it turns out it’s hard to make rules that judges have to follow. Judges are a law unto themselves, and they break the rules. They cheat. If you know someone who’s in law school now who wants a clerkship, they’re probably going to get an offer sometime in their second year. You know, so the middle of their second year and a half before they are ready to graduate.

DUBNER: And what would it take for you to have the authority to get in there and redo that market?

ROTH: Well the question is: is there a desire for judges to coordinate in a way that would control the market? And so far there hasn’t been.

DUBNER: So you can win all the Nobel Prizes you want and there’s a limit to your power nonetheless.

ROTH: There is. 

As complicated as it may seem to match future lawyers or doctors with their employers, consider an even more complicated match: a person who will die unless they can get a kidney transplant.

Ruthanne LEISHMAN: You can’t buy a kidney. You can’t pay for somebody’s college education to get a kidney. You can’t buy them a car. It’s illegal in the United States to obtain a kidney through any kind of valuable consideration. 

That is Ruthanne Leishman.

LEISHMAN: I’m the program manager for the kidney-paired donation program at the United Network for Organ Sharing.

The United Network for Organ Sharing, or UNOS, maintains the registry of all the people in the U.S. who need an organ transplant, at least for now. The Biden administration’s new modernization effort would put some of UNOS’s current responsibilities up for bid. According to the National Kidney Foundation, out of the roughly 122,000 people awaiting an organ transplant, more than 100,000 of them, roughly 80 percent, need a kidney.

LEISHMAN: We don’t have enough supply of kidneys available. And so the list is ever-growing, but the number of kidneys available for transplant is pretty stagnant.

It’s estimated that 13 people die each day in the U.S. while waiting for a life-saving kidney transplant. And that’s because, as Leishman says, the demand for kidneys keeps rising — but the supply hasn’t risen to meet it. Why is that? Consider where most donated organs come from. They primarily come from cadavers — from people who have died but who’ve died under just the right circumstances — from a brain trauma, for instance — to allow their still-functioning organs to be harvested for transplant.

LEISHMAN: Only about 1 percent of the population who die are actually able to donate their organs.

So if you need a heart transplant, let’s say, you are waiting for a cadaver organ. But a kidney is different from a heart. Why’s that? Because humans are born with two kidneys — and yet we really need only one. Which means that in a country like the U.S. with a few hundred million people, there are potentially a few hundred million spare kidneys out there. When someone has kidney failure, typically both their kidneys fail, so they are left with zero healthy kidneys. Whereas the typical healthy person has a perfectly good spare. So while it might seem that there’s a massive demand for donated kidneys — remember, there are more than 100,000 people on the list — the fact is that the potential supply is really massive. Here’s Al Roth again:

ROTH: If you’re healthy enough, you can remain healthy with just one. And that means if someone you love is dying of kidney disease, you can give him a kidney and save his life.

DUBNER: If you happen to be a match.

ROTH: If you happen to be a match. And that’s where kidney exchange comes in. 

Ah, kidney exchange. Because remember, unlike some markets, where price is allowed to let demand meet supply, organ donation is a market that doesn’t allow money. As a society, we’ve decided it isn’t right to reimburse people in any way for donating an organ — although I should say, some economists have argued that we should rethink that. But for now at least, kidney donation is reliant on altruism. Which, judging by the backlog of kidney patients waiting for an organ, isn’t working so well. And that’s why Al Roth got involved.

ROTH: People often ask me how I got involved in kidney transplantation and I think the romantic thing that they’re hoping I’ll say is that I knew someone who was ill or that I was ill, but that isn’t the case at all. I entered through the mathematics. 

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Al Roth — high-school dropout, Nobel laureate, author of the book Who Gets What — and Why — began working on organ donation more than 40 years ago, as it turned out.

ROTH: So in 1974, in Volume 1 Number 1 of the Journal of Mathematical Economics, Herb Scarf and Lloyd Shapley, with whom I eventually shared a Nobel Prize, wrote an article about how to trade indivisible goods when you couldn’t use money. 

DUBNER: And this was a theoretical argument? Entirely, yes? 

ROTH: Entirely theoretical. And sort of whimsically they said, “Let’s call the object houses.” And let’s suppose everyone has a house and people have preferences over houses and they can trade houses, but they can’t use money. All you can do it barter. You can say, “I’ll trade my house for yours.” Or you can do it among three people, you know, “I’ll give you my house and you give someone your house and he gives me his house.” That’s all you can do. How would trade work? So they wrote a paper about that. And I had just gotten my Ph.D. in 1974 when this article came out and I read the article and I thought, “What an interesting problem to think about: how to trade without money.” So I wrote some articles about that too with Andy Postlewaite.

DUBNER: Still theoretical or did you touch — 

ROTH: Entirely theoretical. We were talking about how to trade houses, and of course, no one trades houses without money. I can tell you, I’ve just bought a house in California and money played a role. But the way economists learn about things, the way mathematical economists learn about things is a little bit the way children learn about things. You find toys to play with and then by playing with the toys you gain experiences that might help you with other things. So this is a toy. This toy model that allows you to think about the question of how to trade goods when you can’t use money and when you can’t divide the good. You can’t say, “You have a big house and I have a little house, so just give me half of your house for my house.” You say, “Houses are indivisible. We have to trade.”

In 1982, Roth took a teaching job at the University of Pittsburgh — which happened to have an excellent medical center with a prominent organ-transplant program. Roth began thinking about kidneys from the perspective of supply and demand. Again, there’s a seemingly huge demand for donated kidneys — but in fact a much, much larger supply of potential kidneys for donation, since healthy people have two, but only need one. So let’s say that your spouse, or sibling, or parent needs a kidney transplant. You could voluntarily undergo surgery to give up one of yours — if, that is, you happen to be a biological match.

ROTH: If you aren’t a match, then you’re healthy enough to give someone a kidney but you can’t give the person you love a kidney. So there they are with an indivisible object that we had been calling houses. But now, call it a kidney. And here are these incompatible patient donor pairs and they have an indivisible object, and it’s against the law to buy and sell kidneys for transplantation. So all of a sudden this toy model that we’d been playing with, that didn’t make a lot of sense for houses because we use money for houses, made sense for kidneys.

DUBNER: Was there a light bulb moment for you where you saw that the kidney was the concrete version of what had been discussed in this model or no?

ROTH: Again, I’d like to say that there was but there wasn’t. 

DUBNER: Were you looking for something to plug in to that model?

ROTH: I was looking for a teaching tool. I was teaching the model and my students would say, “This is an interesting model, but isn’t it a little silly. Here in Pittsburgh, we use money for houses, professor.” And I’d say, “Yes, yes but this is a toy model. You should study it.” But there we were in Pittsburgh and we had all these transplants going on and I said, “Well, supposing it’s kidneys.” So we talked about kidney exchange without my ever thinking it would become a practical thing. I was not seeking to design kidney exchange. But in 1998, I moved to Boston to teach at Harvard and in 2000 the first kidney exchange in the United States was done in New England.

That’s an exchange between “incompatible patient-donor pairs” as Al Roth calls them — two couples, let’s say, with the healthy member of each couple agreeing to give a kidney to the needy member of the other couple. The first kidney-paired exchange ever took place in South Korea in 1991; the first U.S. exchange, that Roth mentioned, happened at Rhode Island Hospital, in Providence.

ROTH: And it was covered in the press, it was an unusual thing. And there I was, I had notes about kidney exchange. So with a former student of mine from Pittsburgh who was visiting at Harvard, Utku Ünver, I said to him, “Look at this. There’s kidney exchange. Let’s give a class,” I was teaching a market design class, “Let’s give a class on how we would do kidney exchange.” 

DUBNER: Meaning this one had happened without your help, and you looked at this and thought, “Hey, if this is happening on a small scale, we can maybe —”

ROTH: We can help organize it. We have played all these years with toy models. We know how to organize, on a large scale, trade among people dealing with indivisible goods when you can’t use money. We know a lot about this.

Several other economists began thinking about the problem.

ROTH: And eventually we wrote a paper about how to organize kidney exchange if you weren’t too worried about logistical problems. So we hadn’t yet talked to doctors. We hadn’t yet talked to surgeons. 

DUBNER: Like where the kidney needs to be and what the preparation is for surgery and so on.

ROTH: And how hard it is to do big exchanges compared to little exchanges. So we sent the paper to all the surgeons we could think of, and only one answered. It was Frank Delmonico.

DUBNER: That’s a good one to have answered then, as it turns out. 

ROTH: Absolutely. He was the director of the New England Organ Bank, and he came to lunch and he and I have been colleagues on kidney exchange and on other things for more than a decade now. But we helped him build the New England Program for Kidney Exchange. 

One person that Delmonico hired at the New England Program for Kidney Exchange, or NEPKE, was Ruthanne Leishman, who helped set up their kidney-paired donation program. Remember, the Rhode Island transplant had already happened, in 2000.

LEISHMAN: But that was just done manually looking at the blood types of the donors and the candidates. And then in 2004, we started working with Al and using his optimization program. 

The idea behind using Al Roth’s algorithm was to make it so transplant centers could simply enter the medical and demographic data on potential organ donors and recipients, type in a few keystrokes, and then — voila! — it would produce a match.

LEISHMAN: It would really be impossible to do this by hand because of the number of antibodies that we’re talking about and the number of people that we’re talking about. We really need a computer to look at it, not just to do any kind of matching, but really to optimize the matching.

Matching a potential kidney donor is harder than it sounds. Not only does any given person have one of four major blood types, but we also each have our own stew of antibodies and antigens. We’re born with a certain amount of inherited antigens; but when our bodies encounter foreign antigens, we develop antibodies that battle them. This can happen during a blood transfusion, for instance. That was the case with a Minnesota woman named Julie Parke.

Julie PARKE: What really happened was I broke my leg about, I don’t know, five, eight years ago and unbeknownst to me they gave me a blood transfusion during it. And that just changed a bunch of antigens and antibodies, enough so that Ray no longer was going to be a match for me.

Ray is her husband, Ray Book. They’ve been married for more than 30 years.

Ray BOOK: Julie and I went to high school together, didn’t know each other, had one date when we were freshmen at the University of Minnesota. I told her I’d get back to her, and at our 20-year class reunion I got back to her.

Julie and Ray have one daughter and three grandchildren. Julie has been a Type 1 diabetic since she was eight years old.

PARKE: And it basically has caused all my medical issues over the years. 

Julie got her first kidney transplant when she was 35. It came from a deceased donor.

PARKE: And it lasted me quite a while, and that was great, like 26-plus years. And then that one for whatever reason was failing. So, all of a sudden I needed another one. 

Ray’s blood type is O, which means he’s a universal donor.

PARKE: We were kind of going down that road thinking he’d be able to donate to me someday.

But after that blood transfusion, Julie was told by her doctors that Ray was no longer a match. In Julie’s body, Ray’s kidney would have failed. Ruthanne Leishman is familiar with Julie’s case.

LEISHMAN: She had a lot of antibodies. 94 percent was her antibody level, which means basically she only matches with about 6 percent of the population. 

So if Julie went the route that got her her first donated kidney, it likely would have taken a long time to get another one. Given her particulars, one doctor told her, she could wait five years or more — years which, as Leishman describes, are hard on anyone with kidney failure.

LEISHMAN: And then they’re waiting on dialysis and then three days a week, they go into a dialysis unit to have their blood cleared of the toxins that the kidney usually removes, or they’re at home at night doing home peritoneal dialysis, and so that’s a nightly ritual for people. And it makes it difficult to work. It makes people tired. It makes people sicker, so when they do get a transplant they may not be in the best health anymore, so it’s challenging.

But Julie had the good fortune to be enrolled in a kidney-exchange program. And her chances were greatly increased because her husband Ray was offering to donate one of his kidneys to someone — anyone — since he wasn’t a match with Julie. This is what’s known as being a “paired donor,” meaning that Ray was offering his kidney under the condition that his wife would receive a kidney donated by someone who was a match with her.

BOOK: I wanted to help my wife in any way that I could, so I went out and got tested. All the information went into the computer. We just put it out there into the network and thank god there’s a network like that and the algorithm obviously worked. 

And it worked fast.

PARKE: I went on dialysis November 1st. They called me around Christmas time and told me, “Looks like we got something on the schedule here, but you’ve got to heal this wound you’ve got on your foot.” So I spent the month of January in bed. So anyway, that was January and then we had the transplant February 5th. So it certainly wasn’t five years or more.

The kidney-exchange landscape has changed. There have been consolidations — NEPKE, for instance, has been dissolved under a push to create a national program. And the numbers have grown. Last year, for instance, there were just over 25,000 kidney transplants in the U.S. About one-fourth of those came from living donors — not all from kidney-paired donation, but still: that’s a lot. There’s also a special type of living donor that Al Roth’s algorithm made possible. Ray Book, you’ll remember, was a paired donor; but there’s also room for what’s called a non-directed donor. Ruthanne Leishman again:

LEISHMAN: Somebody who comes into the computer program without a recipient. They don’t know anybody who needs a kidney transplant. They just want to donate to somebody and help somebody. Well they come into the program and they match with a recipient whose donor matches with another recipient, whose donor matches with another recipient, and this can go on and on. And so instead of that non-directed donor helping just one person receive a transplant, they can help two, three, five, 10, 30, 60 people receive a transplant as we go down the line in the chain.

It was one of these incredibly generous people — a non-directed donor — who wound up giving Julie Parke a new kidney.

LEISHMAN: This chain started with a woman named Jodi.

Jodi SHEAKLEY-WRIGHT: Hello. My name is Jodi Sheakley-Wright.

Jodi Sheakley-Wright is 50 years old. At the time, she was living in Charlotte, North Carolina.

SHEAKLEY-WRIGHT: In May 2012, I was working as a telephonic health coach for a company in Dallas, TX, and I worked from home in Charlotte. I had a client who needed to lose 20 pounds so that he could donate a kidney to his sister. And I knew nothing about organ donation at the time. And at first I wanted to do some Internet research to determine how his lifestyle might change after the surgery, as well as what he could expect to do pre-op in order to prepare for the procedure. In my research, I came across something called kidney-paired donation. Wasn’t really familiar with that at first, but I had also seen around the same time an episode of Grey’s Anatomy. It’s actually season 5, episode 5 if you’re interested in checking that out, but it’s about paired donation. And at first, when I had seen it on Grey’s Anatomy, I wasn’t really sure if it was a Hollywood thing or if it really existed. So I did some more research and sure enough it was a real thing and I wasn’t looking to donate, but kind of sat back and thought, “You know, I’m at a place in my life where I think that I’m healthy enough. I work out of my house. I’m financially stable, and this is something that I could do.”

She began working with the transplant center at Piedmont Hospital in Atlanta. She went through a long series of physical and psychological tests.

SHEAKLEY-WRIGHT: They wanted to know if I had considered all of the factors why I should not donate. First and foremost, I was asked to make a few minor lifestyle changes, or at least I felt like they were minor. But things like they didn’t want me to do any death-defying stunts, like ride motorcycles or jump out of airplanes. I had already jumped out of an airplane, so that was okay. But with one kidney, you kind of have to take a little bit more care. So basically they wanted to make sure that I was sure about donating one of my kidneys, because I really only have one to donate. I need the other one to survive and they really want you to think about things like: Are you going to be okay with the decisions that your recipient makes? Meaning that once you give this kidney up, it’s not mine to direct how it’s used anymore. And I was really okay with that. That’s the recipient’s call. I’m giving a gift. 

After passing her tests, Sheakley-Wright’s information was entered into the computer program used by the kidney-paired donor system, and the algorithm went to work on her data. It quickly found a match — Julie Parke, in Minnesota. Less than two months later, it was surgery day.

SHEAKLEY-WRIGHT: My surgery was in Atlanta. First thing in the morning. And once they removed my kidney, it’s put in a Styrofoam container and it’s put on a commercial flight and was flown to Minneapolis. 

LEISHMAN: Her kidney is actually put on a plane and flown to Minnesota, where it is transplanted into Julie. 

PARKE: I think I went in about four in the afternoon, something like that.

LEISHMAN: Julie’s husband, the same day, is having his kidney recovered at a hospital in Minnesota. 

BOOK: It was a very emotional time. I told my kidney, “Go, do a good job and take care of somebody.” And I shed some tears. 

SHEAKLEY-WRIGHT: So Ray’s kidney at the same time that my kidney was flying from Atlanta to Minneapolis, his was flying from Minneapolis to Atlanta for the second recipient in the chain to receive her kidney.

So Ray Book donated his kidney as a paired-donor so that his wife, Julie Parke, could get a kidney from a stranger, the non-directed donor, Jodi Sheakley-Wright. And who got Ray’s kidney?

BOOK: We did find out that it was a woman who got my kidney. And she was in the next room, next to the woman who was donating to Julie.

SHEAKLEY-WRIGHT: Now my recovery room in Atlanta was next door to Ray’s recipient’s recovery room. I had the respect enough not to barge in there and introduce myself; although I have to be honest, I really wanted to. All I know about her is that she’s doing well.

That recipient had also come into the kidney exchange with someone willing to give her a kidney — but she wasn’t a match.

LEISHMAN: So this person in Georgia who received Ray’s kidney, her daughter the same day went to the operating room and donated her kidney. And that kidney stayed right there in the same hospital and went to somebody on the deceased donor waitlist who didn’t have a living donor available to them.

So this one act of kindness by Jodi Sheakley-Wright —

PARKE: Who donated out of the goodness of her heart. She didn’t even have anyone she was donating for.

This one act had a multiplier effect.

LEISHMAN: So what Jodi did by entering the program without a recipient attached to her — she was able to unlock matches that otherwise wouldn’t have been possible.

It also wouldn’t have been possible without the algorithm created by Al Roth and his colleagues. In 2022, there were over a thousand paired-donation transplants.

LEISHMAN: In 2000 we had two. We would have stayed doing two or four or six a year without the algorithm. 

SHEAKLEY-WRIGHT: The entire process is incredible I don’t have that much knowledge about algorithms. It’s been a little while since high school and college so I’d have to revisit some of my math skills, but I do know that it’s amazingly complex and just to match blood types and antibodies And especially knowing that, at this time, there are almost 124,000 people in need of an organ. So how somebody begins to sift through all that is beyond me.

But, thankfully, it’s not beyond everyone. Al Roth again:

ROTH: This is about exchange. It’s called kidney exchange. There’s a real exchange going on. So when I started talking to surgeons, they didn’t automatically think of economists as fellow members of the helping profession. But when I talk about it nowadays, I say, “exchange.” That’s what economists study. Of course this is a subject for economists. But initially many people found it odd that economists were getting involved in organizing surgeries.

DUBNER: You write in the book, or maybe hint in the book, that all this work that you and others have done to try to solve this problem will hopefully be obviated one day not too long from now, when there’s either medical treatment, or perhaps artificial organs, yeah?

ROTH: Oh I hope so. I think that your grandchildren, and maybe mine, will just be appalled. They’ll say to you, “So Grandpa, tell me again. You used to cut the organ out of a dead person and sew it into a sick person and that was modern medicine?” And we’ll have to say to them, “Yeah yeah. We were proud and lucky to be able to do that. It saved lots and lots of lives.”

DUBNER: And even more antediluvian, perhaps, would be the notion that you would have had to create this complicated way to get a living donor to match with a donor, yes?

ROTH: Right. So my hope is that stem-cell technologies will allow you to grow a new kidney the way you grew the ones you had originally. But we’re far from that now. And while that may eventually happen, everyone who has end-stage renal disease today will be dead by that time. So our responsibility is to try to take care of the people who are sick today, even though there will be better ways to take care of them in the future.

DUBNER: What’s it feel like to have played a role in helping redesign, I don’t know if you call this a market, it is a market, yes?

ROTH: I call it a market. I mean, it’s not a market where money plays a role, but it’s exchange and you want to get efficient exchange. You want to get as many and as good quality transplants as you can, so absolutely it’s a market.

DUBNER: So there are a bunch of people out there who are alive who would not have been alive had not you and others working with you done what you’ve done. What’s that feel like?

ROTH: Well, many others. It feels good, but economics in general does good things for people. So I think that it may be an illusion to say, “Here we are saving lives. Isn’t that great?” And it is great. But imagine all the other good things that markets do. You know, the economy has been immensely productive. We all live much, much longer than people like us lived even a hundred years ago. And this has to do with the rapidly increasing prosperity that the world experiences because of the way markets work. So the big job of economists, of market designers, is to help that process along. It’s been going along for many, many centuries without the help of economists, but it goes by trial and error and maybe we can reduce some of the errors and make some of the trials go more quickly and more fruitfully.

That, again, was the economics professor and market-design expert Al Roth. Not long after we first published this episode, we heard from someone who’d been inspired by Roth — inspired to do something that most of us wouldn’t do.

*      *      *

Stephen DUBNER: Okay. Hello, Ned?

Ned BROOKS: Stephen, how are you?

DUBNER: Hey! Great, how’re you? Nice to meet you.

BROOKS: Nice to hear you.

DUBNER: Thanks so much for doing this — I mean doing the interview, but doing the actual deed. 

BROOKS: It was a very easy thing to do. 

When I spoke with him in 2016, Ned Brooks was 65 years old.

BROOKS: I live in Norwalk, Connecticut. I’m semi-retired after a couple of careers on Wall Street and in real estate. 

He had been married for nearly 35 years. Three grown children. And one day, Brooks was in his car.

BROOKS: And we were listening to your podcast about Alvin Roth, the Nobel Prize winner in economics who created a model to trade indivisible items without the use of money. And I think he was talking about houses at the time, but it seems to work very well for the kidney chain as well. And I listen to the podcast with growing interest because what came through to me about the power of the kidney chain, as somebody with a business background, is the concept of leverage. That one altruistic donor — and an altruistic donor is someone who gives a kidney without having anybody particular in mind to receive it. And it provides a lot of options for the people who put these things together, to start a kidney chain. And that results in a sequence of transplants that can affect a lot of people.

DUBNER: Now, have you ever considered giving a kidney before then?

BROOKS: No, no I did not. 

DUBNER: And what was it about the message from Al Roth in that podcast that either alerted you — what did you learn, or what changed your mind that made you start to think about that then? 

BROOKS: Well, the concept that we have two kidneys and we only need one.

DUBNER: Now did you know that ahead of time, or not really?

BROOKS: Yes, I did know that much. What I did not know is all the benefits that accrues to one who donates a kidney. The process is lengthy in terms of the amount of testing that you go through to do so.

DUBNER: Now, you’re saying that the medical tests were the benefit?

BROOKS: Oh absolutely.

DUBNER: I just want to clarify here.

BROOKS: Absolutely. Look, you get many thousands dollars of testing for free. 

DUBNER: Can I just say something, Ned? I think you and I are fundamentally different people, because if I were going to get several thousands of dollars worth of something free I would want it to be, you know, golf, or something, fishing boat. Not medical testing, but tell me more about your great desire —

BROOKS: Well, you’re not 65, and knowing that all your organs are free of any contaminants is a very reassuring thing actually. 

Let me be clear. It wasn’t really all the free medical testing that made Brooks want to become a kidney donor.

BROOKS: I think this is something I have to do. It required some thought, discussion with my wife that day in the car. I spent one restless night, probably about three hours trying to understand what my own motivations were and if they were the right ones to be doing this. And once I put that to rest, then it was a very easy thing to do. 

DUBNER: Did you decide immediately to become a non-directed donor? Meaning that your kidney would be available for anyone who needed it? Or, did you think about trying to help someone in particular?

BROOKS: As great as it would be to help someone in particular, I didn’t know anyone who needed a kidney. And in fact, the leverage comes from being an altruistic donor. You can’t start a kidney chain unless you’re altruistic about it.

DUBNER: Let’s say I need a kidney and my wife is willing to donate or someone else in my family is willing to donate, but they’re not a match. They’re not a physiological match for me. But they would donate a kidney of theirs to someone else who is a match. They then enter the chain, correct? 

BROOKS: So, call them “couple A.” And Couple B is in the same situation as is Couple C, D, down the line. 

DUBNER: But then there is this wildcard, X, that’s you. This guy who comes in that doesn’t have anyone that needs one, that just wants to give. Does that make you much more valuable?

BROOKS: That makes me valuable because it allows the algorithm to maximize the length of the chain and kick it off. If you didn’t have the altruistic donor to start, you’d have to have a perfect match. I’m trying to — I’m working with my hands as I’m doing this — which is a lot of arrows pointing to people who all work out exactly the same. 

DUBNER: Talk about the procedure, working with the hospital, and talk about how the relationship works so that you are not made to feel that you’re being pressured.

BROOKS: Sure. In my case I had the operation done at New York-Presbyterian. And I chose New York-Presbyterian because they do a lot of these operations. And I think that with any surgery like this you want to go to a place that does a lot of them. And so I was very comfortable with their record. They’ve never lost a donor yet. They provide you with two advocates. And those advocates are there to protect your interest throughout the process. And you go in for testing, you do it through your advocate, you go in for psychological testing, physical testing. They want to make sure you are financially able to this, because, of course, you cannot be compensated for a kidney donation.

DUBNER: To what degree did they push back? In other words, to what degree did they try actively to discourage you or at least make you take a step back and think it through a little bit more?

BROOKS: They didn’t actively discourage me. The psychiatrist probed quite a bit. But after I seemed to have satisfied her on the answers, that was the end of it. What they will not do is they will not come after you to keep you coming to hospital for every procedure that needs to be done. In other words, they set the time and the date for your next appointment, and they won’t call you. It’s up to you to make sure that you’re there.

DUBNER: Oh that’s interesting. And at no point did they catch on to the fact that you were just in it for the free medical testing?

BROOKS: Actually yes. The doctor I spoke with there said, “This is a little-known secret, but the testing is so good that everyone should at least start out to be a kidney donor and find out how their tests go.”

DUBNER: That is a secret that I’m guessing they really don’t want broadcast. Because I can see an army of senior citizens flooding in for their tests saying, “You know, I think I’m going to hang on to the other kidney.” And then talk to me about your family’s response. Was everyone on board?

BROOKS: My wife was supportive. As I said, I have three children. One was very supportive, one was skeptical, and one was opposed. And I guess that’s what you get when you get three children. But the skeptical one, and the one who was opposed, turned around once they felt like they got a lot more facts about it. It’s a very safe procedure relative to surgery, in general. And once they understood that, I think their reservations went away.

DUBNER: I understand you wrote a letter to your family when you had gotten pretty far along in the process. By then you’d undergone some of the testing? 

BROOKS: Yes, yes. 

DUBNER: Do you have that letter handy?

BROOKS: Actually I do have it here. 

DUBNER: If you don’t mind giving that a read, that would be great. 

BROOKS: Sure. This is a letter that I wrote to my family when I realized that it was what I wanted to do, and I wanted to inform them all at the same time. So, I sent them an email and it goes like this: 

All, as you have commented upon, I have had a number of medical tests over the summer. I did not fully answer your questions about those cause I wanted to wait until I had cleared all the tests. I’m happy to report that I’m about as healthy as is possible for a 65-year-old male to be. Back in the spring, I was listening to a Freakonomics podcast about a man who won the Nobel Prize in economics for constructing a model of a market to trade indivisible objects without the use of money. He was thinking about houses, but it turns out that the model works very well for other things. His work had been used to create an extensive network for the matching of kidney donors and recipients. The more I listened to the podcast, the more fascinated I became as I learned that just one altruistic donor — a person who donates without a targeted recipient — can launch a chain of kidney transplants that can number as high as 43. I spoke with the National Kidney Foundation and learned more about the process. I registered as a potential donor and began extensive series of tests at New York-Presbyterian, which have now concluded as be being accepted as a kidney donor. So why am I doing this? Many of our friends and acquaintances have had their share of health challenges in recent years. It is mightily frustrating to watch the pain and suffering and be unable to give any help. I, on the other hand, am in perfect health. I have no need for my second kidney, and I appreciate that my actions may greatly benefit the lives of not just the recipients of those kidneys but their entire families. Without it being too much of a stretch, my one wholly redundant organ can potentially change and improve the lives of hundreds of people. There were 5,355 kidney transplants from living donors last year, and there are over 100,000 people on the waitlist right now for a kidney. The operation is several hours. They start about 3am in order to catch the morning flights around the country, particularly Los Angeles. L.A. does more transplants than any place in the country, and New York Presbyterian does the most east of the Mississippi. They’ll have me walking that same day, and I should stay two days in the hospital. I’ll be uncomfortable for two weeks, and fully recovered after four weeks. The operation is laparoscopic, with a single incision in the abdomen. I’ve been working hard with my trainer on my abs. My advocate tells me that because I am blood type O, a universal donor and an altruistic donor, I will light up computer screens across the country when they list me tomorrow. I am happy to report that mom is fully on board with this. I could go on for a while, but I think you have the picture. If you have interest in hearing the podcast that inspired me, you can find it here — and then I note the Freakonomics page — and the short Freakonomics blog on the subject here. Let me know if you have any questions. Love you all, Dad. 

The left kidney that Brooks donated wound up launching a three-recipient chain.

BROOKS: I knew nothing about my recipient until the day of the surgery when I was told that it was a 37-year-old female in the Denver area and that she was very, very sick and unlikely to find a donor anytime soon. And that this was a real one-in-a-million match.

DUBNER: Did you know anything about the cause of her illness? And would that have mattered to you if you did know?

BROOKS: No, I had no idea. 

DUBNER: Look, you’re not getting paid; you might get thanked, you might not get thanked. You’re doing this for your own set of reasons. Was it important to you that that person appreciate those reasons, or appreciate you? Or did it not really work that way for you?

BROOKS: This is where the leverage comes in. They ask that same question in the initial stages in a little bit different way. What they ask is, “If something happens to your recipient, how upset are you going to be?” Quite frankly, my answer was, “This is multiple people who are getting a transplant because of what I’m doing. And if one of them doesn’t work out, I’m terribly sorry, but it’s going to change the lives for all the others.” 

DUBNER: So Ned, you learned a little bit about your recipient, and from what I understand, you’ve been in contact — you’ve received a letter from her — is that right? — expressing her thanks.

BROOKS: The way this works is I go through my advocate at the hospital writing a letter to the recipient that goes through the advocate at her hospital to her. Then if she chooses to do so, she comes back to me with whatever she wants to say. And then through the advocates I go back and disclose my identification, then she does that back to me if she wants to. And that’s the way it worked. And we’ve exchanged emails. I’ve gotten Christmas cards and such from her family and so forth. 

DUBNER: So you haven’t met with her or spoken with her by phone? 

BROOKS: I have not met or spoken to her. 

DUBNER: Okay so, here’s the story, I believe that if technology has served us well that she’s on the other line right now. Danielle from Centennial, Colorado.

BROOKS: Oh my god! I’ve not spoken to her yet! This would be great. 

DUBNER: Danielle can you hear us? This is Stephen Dubner. 

DANIELLE: Hi, I can hear you guys.

BROOKS: It’s Ned.

DANIELLE: Hi Ned. 

BROOKS: Hi. 

DANIELLE: How are you doing?

BROOKS: I’m doing great. 

DANIELLE: Good, good. This is exciting. 

BROOKS: This is very exciting. It’s great to hear your voice. How are you feeling?

DANIELLE: I’m doing good! I’m feeling real good. Lately, it’s been a struggle since the surgery but I’m doing good — a lot better than I was. 

BROOKS: Are you on lots of meds? 

DANIELLE: Yeah, unfortunately, I’ll have to be on a ton of meds for probably the rest of my life. 

DUBNER: Hey Danielle, this is Stephen. Can you tell us a bit about what led to your need for the kidney?

DANIELLE: Sure, sure. It all started October 8, 2014. I had received a call from my doctor saying that my blood work had come back — I’d gone to my regular doctor just ‘cause I was having a severe headache that wouldn’t go away. And so they did some blood work, they called me the next day and said, “You need to get to the hospital immediately.” They were telling me creatinine was at a 12 and I had no idea what that was. And so, I went to the hospital and was immediately hospitalized for the next 15 days, getting biopsies and M.R.I.s and plasma freezes and dialysis and getting all these tubes put in my neck and chest. It just all happened so fast. To this day, they still don’t have any reason. It happened three weeks after I had my son but they don’t want to associate it to that. So they really have to answers of why this all happened to me.

DUBNER: And what was your, a) I guess, prognosis? Did they think that you would survive? And what was your prognosis for getting a donated kidney?

DANIELLE: Well, when I was hospitalized and they had no answers, and they were functioning a small part, but they said that they were failing. But they had hope — since they really had no idea what was going on with me — that they would kind of kick back in and restart themselves. So we kind of just waited and I started dialysis and everything. And while we were waiting for those next couple months, I actually tried acupuncture for organ treatment, specifically for that. You know, I was trying everything. And I said, you know what, I’m not going to wait any longer for them to restart. I better get on this transplant list now. So, come January of 2015, I started the process of getting on the transplant list. And starting there. 

DUBNER: And what were you told about how long that would likely take you to get you a donated kidney?

DANIELLE: Well, it came back that I had antibodies in my blood from blood transfusions that I had during the hospitalization, and from having children they said I had created all these antibodies. So it made me a very rare match for — I wasn’t a match to any of my family and so they said because of my rare antibodies I could possibly be on the list five or six years. So that’s the kind of range they gave me back in January of 2015. That, I was looking at five to six years being on dialysis. 

DUBNER: Wow. How long was it before you heard that there was a donor?

DANIELLE: Well, it was probably come May of 2015 that I started getting word. Me and my father, we decided since I was having such a hard time and nobody in my family matched with me, my father really wanted to donate on my behalf. So we heard about the paired-donor program through the hospital and he wanted to donate his kidney on my behalf. So, it was probably around May of 2015 that we started the chain process. I had several chains lined up throughout the summer of 2015 but it kept falling through due to scheduling with some part of the chain — it kept falling through. So I had many chains lined up throughout the summer, and it was finally in August that we found — I guess Ned was matched to me, and we got the surgery date of Sept 22nd, and it kind of just happened really quickly from there. 

DUBNER: Way to go, Ned. 

BROOKS: Thanks. 

DUBNER: What’s it feel like for you, Ned, hearing Danielle talk now? She’s obviously in a much better situation today with your kidney in her than she would be without. So what’s that feel like to hear her on the other end of the line? 

BROOKS: Um, it’s emotionally very powerful. It means a lot. A great deal. 

DANIELLE: Yeah, it was a real struggle going through dialysis in the last year. I had to do four hours of treatment three days a week. So basically it took 15 hours out of my time every week. And I would go into a dialysis center. And, the first thing you do is you get checked in and they do your blood pressure, your weight, your temperature. They go through all your symptoms that you’re feeling. There’s really no privacy when they’re doing that — I mean, the next patient is five feet from you in their chair, and you’re talking about all of your bodily functions that are not going well for you with all the medications you’re taking and everything and it takes away a little bit of your integrity having to do that so publically. And then, just to sit there for four hours doing nothing — I can’t get up, I can’t move. My blood is just sitting there, you’re watching your blood go through this machine and it’s really, really depressing. And, it was hard for me. I mean, I cried the first couple times just because I would sit there and I’d look around and I was the youngest, you know obviously, in the whole building. I was 37 years old. And I was the only one driving myself there. It’s just a really hard and depressing time to spend in your day. It was really hard for me to do because I have two small children as well.

DUBNER: It’s remarkable — you say you were crying then. Now you sound so strong. Ned’s on the other line blubbering there. I’m on the border, holding it together.  

DANIELLE: It’s emotional every time I talk about my story too.

DUBNER: I’m curious — you said that your dad had entered the donor chain. Did he end up giving a kidney, and if so does he know who the recipient was?

DANIELLE: He ended up giving his kidney. And all we really know is that it went to Connecticut over there where Ned is, and we have not heard from the recipients on that end. 

DUBNER: I have a copy of the letter that you wrote to your donor. It’s unclear to me whether you knew exactly who Ned was at this time. It begins, “To my wonderful kidney donor, I don’t even know where to begin.” — and I’ve already started to cry, sorry. I have nothing to do with either of you, and I’m crying. Okay. So, but then, toward the end, you write, “Just to let you know, your kidney is doing awesome, and I’m already getting my energy back.” Danielle, what’s it like to have this guy Ned’s kidney inside of you? Do you feel whole again? Do you feel different?

DANIELLE: You know, it was amazing because the very next day after surgery, I felt incredible. I felt 100 percent different. I didn’t feel any of the symptoms that I was having before with the illness and the nausea and the anxiety and everything I was going through. I immediately felt better. My body felt better, and yeah. I was eating and drinking the foods and liquids I was restricted to for so long, and it’s just — I do have the energy again. It’s amazing how much better I feel. And I don’t know if he had any food habits that I’ve picked up —

BROOKS: How do you feel about single malt scotch?

DANIELLE: You know, I haven’t had the craving for any scotch. It is funny because we joke about that with my dad because he’s a single malt scotch drinker too — and we say, “Oh, that person’s probably craving it now.”

DUBNER: Well, Danielle, I’m glad you’re doing better and I hope you continue to do even better. 

DANIELLE: Yes, thank you so much. And Ned, thank you so much for everything you’ve done for me and my family. 

BROOKS: No need to thank me anymore. Thank you for being such a great recipient, and we’ll be in touch. 

DANIELLE: Yes, we will. Thank you. 

DUBNER: Danielle, thanks for jumping on the phone with us. Bye bye. 

DANIELLE: Alright, bye guys.

DUBNER: Bye. Well, Ned, how do you feel now? See what you’ve done now?

BROOKS: Boy, I was shaking in here. This is really something. She’s a great person. 

DUBNER: Well, I know you didn’t do it for the thanks, but thanks! 

BROOKS: My pleasure. 

Ned Brooks, inspired by his own experience — and the need for more kidney donations — started an organization to help build more altruistic kidney-donor chains. It’s called the National Kidney Donation Organization. Last year, they helped recruit about 600 living donors. They can be found at NKDO.org.

*      *      *

Freakonomics Radio is produced by Stitcher and Renbud Radio. The original episode, “Make Me a Match,” No. 209, was produced by Greg Rosalsky, and the conversation with Ned Brooks originally aired as part of an episode called “Ask Not What Your Podcast Can Do for You,” No. 237, produced by Arwa Gunja. Our staff includes Julie Kanfer, Zack Lapinski, Morgan Levey, Ryan Kelley, Alina Kulman, Katherine Moncure, Greg Rippin, Rebecca Lee Douglas, Sarah Lilley, Eleanor Osborne, Jeremy Johnston, Jasmin Klinger, Daria Klenert, Emma Tyrrell, Lyric Bowditch, and Elsa Hernandez. The Freakonomics Radio Network’s executive team is Neal Carruth, Gabriel Roth, and Stephen Dubner. Our theme song is “Mr. Fortune,” by the Hitchhikers; all the other music was composed by Luis Guerra.