Make Me a Match (Ep. 209)

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Market-design wizard Al Roth finds solutions for the problems money alone can’t solve. (Photo, cropped: Newtown Grafitti)

Our latest Freakonomics Radio episode is called “Make Me a Match.” (You can subscribe to the podcast at iTunes or elsewhere, get the RSS feed, or listen via the media player above. You can also read the transcript, which includes credits for the music you’ll hear in the episode.)

The gist of the episode: Sure, markets generally work well. But for some transactions — like school admissions and organ transplants — money alone can’t solve the problem. That’s when you need a market-design wizard like Al Roth.

Al Roth, an engineer by training, is a professor of economics at Stanford and won a Nobel in economics in 2012. (Roth shared the prize with Lloyd Shapley, whose research influenced Roth). What kind of work did Roth do to land the Nobel? It’s not the kind of thing that typically wins a Nobel. Roth 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, you know, 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.

Roth has also just published a very fine new book that is a great survey of his work — and his worldview, which is just as impressive. It’s called Who Gets What—and Why: The New Economics of Matchmaking and Market Design In the podcast, I visit Stanford to speak with Roth about market design, what’s it’s like to get that middle-of-the-night Nobel phone call, and why the world needs an economist-engineer like him in the first place:

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.

You’ll hear how Roth and others have revolutionized the organ-donor market, and we hear the amazing story of how one particularly selfless woman kicked off a donor chain that gave life to many others. And you’ll also hear Ruthanne Leishman, from the United Network For Organ Sharing, talk about  the organ-donor algorithm developed by Roth and his colleagues:

LEISHMAN: It’s saving a lot of lives. We have about 600 kidney-paired donation transplants a year right now in the United States. In 2000, we had 2. … We would have stayed doing 2 or 4 or 6 a year without the algorithm.  

The next time you hear someone say that economists are a bunch of selfish good-for-nothings, feel free to counter by telling them about the fine work of Al Roth.


I enjoy the program a lot. I hope the program continues to go forward for the years to come. This episode was very interesting and enlightening especially on how the exchange market for kidneies work. In the program you mention that some economists believe people should be able to sell their kidneies. I don't know if there has been any studies on this subject or not but in my home country, Iran, people can sell and buy kidneies. If there can be a discussion on this as an added bonus to this episode it would be amazing. I'd be happy to help.



While listening to this episode, I have this bizarre idea running through my head. What if the organ exchange program create a new concept similar to “Pay it Forward”, where a volunteer donor who choose to donate his/her kidney and in return he/she will be put on the top of the kidney transplant if he/she needs a transplant later in life. This is under the assumption that there will are strict governing organizations that will reinforce such rule.

Studies have shown that humans can live normally on just one kidney. So why not buy yourself extra time by giving up one of your health kidney to a person in need and in return you would have secured yourself priority spot to receive a kidney if you ever need one (hopefully you never need to tap into this feature). Because chances are if your kidneys fail, both will fails around the same time frame due to your life style, disease and etc…

In an ideal world, everyone behaves in this altruistic way the US should never run out of health kidneys. There are 300 million people in the country, and let’s assume just about a quarter of the population is qualify to donor their kidney. Let’s cut that number down again by say 99% because not everyone is that excited to give up one of their kidneys. If my calculation is correct, there’s roughly 750K willing donors available.

I personally view this as one of the most altruistic act and selfish act at the same time, since you are giving a stranger a chance for new life while buying yourself an option to cut the line in the later stage of your life and denying someone else a chance.

If any of this makes any senses, let me know and I will share a few more thoughts otherwise please ignore.




I had the same idea. It occurred to me when I asked myself: will you donate a Kidney now? My answer was: no, not now, out of consideration that my wife or children might need one later. If my wife and children could be added to a guaranteed priority list for possible future use, I would consider donating now, and my second kidney could be given years of extra service. I'm sure Nobel laureates and others have thought of this too; would have been interesting to hear why it's not been implemented.

James B.

Here's a different take on this organ donor subject. What if people actually don't need their organ replaced? What if medical care is available, which could get the body to heal its own organs? One holistic doctor I've gotten several rounds of treatment from practises a form of Asian medicine where he reenergizes meridian links in the patient's body. He can get organs, which have shut down, to start working again. His website is He claims there are only about a 100 doctors in the world who practise this kind of medicine.

So, why aren't we giving more attention to alternative practices, which are far more effective than those offered by the profit-driven, pharmaceutically centered establishment?


Because it doesn't work?......

Ollifant Chuckerbutty

The economics of organ donation do not add up for me.

For the cost of one transplant, it would be possible to save a much greater number of people from other types of sickness.
Is this some kind of a scam by the medical community.
According to the show, the total number of transplants is in the several thousands. If we assume the cost per transplant, including full lifetime care is about 500,000 $US, It is in the billions (US) (This is 260,000 up front and the rest in 1000$/month for the immunosuppresives.
Can you guys figure out why this cannot be allocated in a more efficient manner?
The same for Dialysis.
The fact that we can do something, does it mean that we should do something.


Whose money is it, though? If I happen to have $500K, and want to spend it on a kidney transplant that will presumably save my life, why on Earth do you think I'd be altruistic enough to spend that money on other people?


Does UNOS incentivize this program?

In the case of Jodi's story, would the kidney have gone to the first patient even if they did not have a partner willing to donate? Is so, why would the first patients partner agree to donate? If not, does that mean that there are people with lower UNOS Match scores getting kidneys?

Does the algorithm favor longer and longer chains? Does being part of a longer chain improve your unos score?

It seems to me that being part of a complete circle (A->B->C->A) does increase your odds of being part of a group match, but unless incentivized, being part of a chain (A->B->C->D) only means that your partner is agreeing to donate with no real benefit to you? If you are C in this case, why bother having a partner, you would have gotten B's partner's kidney anyway. If you're B the Same thing holds.

As a result, this system might suffer from free loader problem, where everyone would benefit from a thickening of the market, but each individual won't, so very few do.


Enter your name...

There should be a limit to the length of a chain, for practical reasons. A transplant surgeon can only do one at a time, and even if you had hundreds in town for a convention, then having too many transplants in a single facility on the same day might result in worse care for the patients.


Hi there,

Interesting show but one thing you kept bringing up was the "fact" that you have a spare kidney or that donors are unharmed by the operation. I donated a kidney last year and before that had a real hard look at the papers and this is completely unsupported by the data.

Aside from the 1 in 3000 chnce of death during the donation and a 1 in 20 chance of a serious complication during the operation (tears to bowel, adrenal gland, spleen, nerve damage) and a fair chance of post operative hernia or wound infection kidney donors are living with reduced kidney function through the rest of their lives as the other one doesn't pick up all the slack (although it does its best)

The comparison they doctors make is that donors live as long (or longer) than the general population. Unfortunately that doesn't hold water - donors can't be overweight, have high blood pressure, are non smokers etc. and are screened for heart disease, cancer, existing kidney problems,... so the comparison should be against a similarly screened very healthy subset of the genral population. And no-one has really done that comparison in a well controlled way despite the decades of living kidney donors. The closest we have to that is a Norwegian study that looked retrospectively at a similar population and found that donors have a 40% higher rate of cardiovascular death and 1100% higher rate of kidney failure.

A show on the data supporting and ethics of living kidney, liver and other donations would be really interesting.

To the questions below about living donors going to the top of the list - in the UK you get priority for an organ if you donated while in the US you get additional points in the ranking system but you really don't want to have to rely on it.


Richard Tomasello

After listening to this episode, I began to wonder how could we bring more donors to the market in order to save more lives. The idea that the algorithm can match those in need of a kidney with the donors and the effect of one kidney donor can be multiplied by starting a chain of multiple recipient and donor pairs is an amazing benefit to the system. But my concern as a healthy individual that may be willing to become a non-directed donor in hopes of starting a chain that could have a positive effect on several lives is that one day someone close to me will need a kidney that I no longer have available. On top of the personal grief that I would feel knowing that I could have helped a loved one, I can imagine my mother-in-law chastising me because her daughter, my wife, is sick and "he already gave his kidney to some stranger 15 years ago".

In order to avoid this situation, is it possible for healthy non-directed donors to receive a "kidney credit" allowing that individual at some time in the future, if the need arises, to move a loved one to the top of the donor list. I assume preferential treatment is currently given to the paired donor/recipients that are themselves wanting to use the algorithm to find a worthy match. The problem that I see with this is that if a donor is issued a kidney credit, it seems more liquid and transferrable to the highest bidder than an actual kidney is. Meaning that I as a person who has willingly given away one of my kidneys may now be swayed by a benefactor to suddenly claim that this person is a long-time family friend that I will allow to use my kidney credit. But then again, what measures are currently in place that keeps someone from paying a willing donor to make this claim and become a paired donor for a specified recipient?

I would also like to hear what economists feel are the dangers, benefits, and uncertainties of having a free market for organs. I am sure this podcast episode will generate a lot of responses, so hopefully we will get a follow-up episode.

Your podcasts are great and the books are even better. I look forward to reading "When to Rob a Bank" during my 4th of July vacation weekend.

All the best,



I found this episode to have particularly low bandwidth. While the interviews were cute, they were not as informative as an in depth discussion of the facts. And we never really heard Al Roth discuss his theories in any detail. All in all, the useful information could have been revealed in 5 minutes, rather than 50. I don't have time for these "chatty" podcasts, although they seem to be increasingly popular. I dropped Steve Gibson's podcast because the bandwidth was so low.

Dr Okoduwa Godwin Solomon


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