Friday, February 12, 2016

Federico Echenique and Juan Pereyra on unraveling of matching markets

 Strategic complementarities and unravelingin matching markets 
by Federico Echenique  and  Juan Sebasti├ín Pereyra, Theoretical Economics 11 (2016), 1–39

 Abstract: We present a theoretical explanation of inefficient early matching in matching markets. Our explanation is based on strategic complementarities and strategic unraveling. We identify a negative externality imposed on the rest of the market by agents who make early offers. As a consequence, an agent may make an early offer because she is concerned that others are making early offers. Yet other agents make early offers because they are concerned that others worry about early offers, and so on and so forth. The end result is that any given agent is more likely to make an early offer than a late offer.

Thursday, February 11, 2016

Using deceased donor kidneys to start some kidney exchange chains

It would save some lives... here's a link to the abstract of a forthcoming paper (more like an editorial, really).



We propose that some deceased donor kidneys be allocated to initiate non-simultaneous extended altruistic donor chains of living donor kidney transplants to address in part the huge disparity between patients on the deceased donor kidney waitlist and available donors. The use of deceased donor kidneys for this purpose would benefit waitlisted candidates in that most patients enrolled in kidney paired donation systems are also waitlisted for a deceased donor kidney transplant and receiving a kidney through the mechanism of kidney paired donation will decrease pressure on the deceased donor pool. In addition, a living donor kidney usually provides survival potential equal or superior to that of deceased donor kidneys. If kidney paired donation chains that are initiated by a deceased donor can end in a donation of a living donor kidney to a candidate on the deceased donor waitlist, the quality of the kidney allocated to waitlisted patient is likely to be improved. We hypothesize that a pilot program would show a positive impact on patients of all ethnicities and blood types.


I've recently updated my game theory, experimental economics and market design page, and you can find some updated papers on kidney exchange at , and on deceased organ donation at 

Wednesday, February 10, 2016

Public comments at the SEC about IEX's exchange application: a seminar on the politics of market design

There's an exciting (if confusing) practical seminar on market design going on on the SEC's webpage these days, where they are posting comments on IEX's application to become an exchange.

First, here are some background news stories:

Matt Levine at Bloomberg, in December: The 'Flash Boys' Exchange Is Still Controversial

Robin Wigglesworth at the FT, this month: ‘Flash Boys’ trading venue application triggers backlash
"The Investors’ Exchange, a trading venue made famous by Michael Lewis’ Flash Boys book on high-frequency trading, has applied for full stock market status. But the application has triggered a deluge of responses and fanned the debate about the very nature of the US equity markets...."

And here is the SEC's comment page, a sort of flash mob exchange about markets and market design.

Guide to the perplexed: I like Eric Budish's comment, here: #371 …

About how to go through the many other comments, Eric writes: 
"For pro-IEX letters, the best place to start is the detailed letters from IEX itself. The letter from Healthy Markets is also very good on details. The letters from Southeastern Asset Management (co-signed by many other asset managers) and from Norges Bank (Norway’s sovereign wealth fund) are a bit shorter but give a sense of how pro-IEX asset managers see the debate.
For negative letters, the letters from trading firms Citadel and Hudson River Trading are quite detailed. The letter from NYSE has the distinction of being both detailed and comparing IEX to the fraudulent frozen-yogurt shop on Seinfeld.
Also recommended is the letter from Goldman Sachs, which, like my letter, supports IEX’s application but mostly talks about deeper structural issues."

You can search the comments, e.g. for "IEX"  or "Goldman Sachs," etc. to find them... 

Tuesday, February 9, 2016

Military draft registration, now for women as well as men?

The recent discussions of draft registration for women have invited us to recall the discussions about conscription versus a volunteer army. This, from the Sunday NY Times:
Economists Against the Draft By BINYAMIN APPELBAUMFEB. 6, 2016

One argument that I hadn't recalled being made in just this way is that the wealthy manage to avoid drafts better than the poor, so that even a conscripted army tends to be manned (if that's still the right word) disproportionately by poorer people, but that at least the financial costs of a volunteer army fall on the taxpayers, while the financial costs of a conscripted army fall on the conscripts and their families.

The discussion about conscription versus a volunteer army brings up some issues that also arise in discussions about whether organ donors may be compensated.

Monday, February 8, 2016

A WSJ reporter prepares for Valentines Day by interviewing economists about dating sites

Here's a WSJ interview that mentions, among other things, Soo Lee and Muriel Niederle's experiment with virtual roses:

How Economists Would Fix Online Dating
A ‘thick’ market and cost-benefit analysis help avoid ‘romantic unemployment’

"One recent experiment in improving online dating sites through signaling mechanisms, conducted by economists Soohyung Lee and Muriel Niederle, gave members of a Korean dating site a limited number of virtual roses, meant to indicate special interest in a person, to include with their messages to potential matches. The result was that people were more likely to respond to those who sent them a rose..."

Sunday, February 7, 2016

Mishaps while flying transplant organs

This news story stopped with the plane, and doesn't say what happened to the organ...
No one hurt when jet scheduled to pick up donor organ slides off runway in Wheeling

Repugnance for money: The Other Paris, by Luc Sante

Paris is romanticized as the opposite of NY, and poverty as freedom from money, in this review in The Guardian of The Other Paris by Luc Sante

"“My book is a kind of love letter to the city as it was and before it got overtaken by money. Money, for me, may not immediately kill people in the way terrorism does, but it does certainly change the fabric of daily life in much deeper and more insidious ways. The terrorist may be defeated in 50 or 20 or 10 years, but money is going to be much harder to defeat.”

Saturday, February 6, 2016

Repugnant transactions in zoos

The NY Times ran the following story a little while ago:
Zoo’s Public Dissection of Lion Makes Denmark Again a Target of Outrage

"On Thursday, staff members at a zoo in Odense, the country’s third-largest city, publicly dissected the corpse of a 9-month-old lion in front of an audience including children. The lion, a healthy female, was put to death in February after the zoo sought in vain to find her another home.

"The move comes more than a year after another Danish zoo, in Copenhagen, generated global outrage when it killed a healthy 2-year-old giraffe named Marius, ostensibly to reduce the risk of inbreeding, before dissecting him and feeding him to lions.
"Ms. Christensen said the lion was put down to prevent inbreeding, since she was living in the same enclosure as her father and the two would have been likely to mate. The lion had since been kept in a freezer.

"She noted that while it was a preference in some countries, like the United States, to use contraception to keep zoo populations under control and prevent inbreeding, many zoos in Denmark and across Europe considered it better for animal welfare officers to let animals breed and express their natural instincts, even if that meant culling some of the offspring, as a last resort, for reasons of conservation."