Monday, January 22, 2018

Pursuing Global Kidney Exchange in Rome: photos

I was recently in Rome, where a substantial group gathered (see below) to further the possibilities of Global Kidney Exchange (GKE). Part of our efforts were focused on presentations to a January 15-16 Meeting of the EU Competent Authorities on Organ Donation and Transplantation, Co-Chaired by the European Commission..

You can see a photo of Mike Rees beginning his talk, with the names of various co-conspirators.
Finally, there's good coffee in Rome. I recommend the famously good San Eustachio.

So far, the EU competent authorities haven't issued any statement.

Sunday, January 21, 2018

The number of organ donors in Germany has fallen to its lowest level in 20 years.

Rosemarie Nagel draws my attention to this article in Der Spiegel on transplantation in Germany:

Wieso werden in Deutschland so wenige Organe gespendet?
Die Zahl der Organspender in Deutschland ist auf den niedrigsten Stand seit 20 Jahren gesunken. Woran liegt das? Und wie kann man einer Spende zustimmen - oder sie ablehnen? Der √úberblick.

Google translate renders it as: Transplantation
Why are donated so few institutions in Germany?
The number of organ donors in Germany has fallen to its lowest level in 20 years. Why is that? And how can you agree to a donation - or reject it? The overview.

Friday, January 19, 2018

Bob Wilson, Paul Milgrom and Dave Kreps win the Carty Award

Game theory at Stanford:)

Here's the press release from the National Academy of Science

David M. Kreps, Stanford University Graduate School of Business, Paul R. Milgrom, Stanford University Department of Economics, and Robert B. Wilson, Stanford University Graduate School of Business, will receive the 2018 John J. Carty Award for the Advancement of Science.

"Kreps and Wilson provided a framework, known as sequential equilibrium, for modeling dynamic effects in economics. All three of the award winners, together with other collaborators and in particular D. John Roberts, employed these techniques to model and study reputation and collusion, both of which have broad applications in macroeconomics, industrial organization, and labor economics.
Later, the entire modern telecommunications industry arose out of an auction format developed by Milgrom and Wilson, along with Preston McAfee, for the 1994 radio spectrum auctions by the Federal Communications Commission. The simultaneous ascending auction format, in which each bidder can bid for multiple licenses over a series of rounds so long as it remains “sufficiently active,” has since been used around the world to allocate hundreds of billions of dollars’ worth of wireless licenses. Variations of the format have also been applied to numerous other industries, including electricity markets and various commodity markets.  
The three award winners, with collaborators and alone, have contributed broadly to other topics in economics: Kreps has done foundational work in choice theory and financial market theory; Milgrom, in the theories of market microstructure and the principal-agent problem; and Wilson, in nonlinear pricing and utility regulation, as well as the foundations of dynamic equilibria.
The John J. Carty Award for the Advancement of Science is awarded every two years, to recognize noteworthy and distinguished accomplishments. In 2018 the award is presented in the field of economics. The award is presented with a medal and a $25,000 prize."

Thursday, January 18, 2018

Evolution of dating apps: OK Cupid requires mutual consent for messaging

Slate reports (last month):
OkCupid Users Have Long Had to Put Up With Unwanted Messages. That's About to Change
"OkCupid announced a big change to its messaging system in an email to users on Friday afternoon. Starting next week, the email said, “Only the people you like or have responded to will remain in your messages. Messages from people you're not interested in, or people you haven't liked yet, will be moved to their profile.”
"This shift will bring the platform more in line with other online dating platforms, such as Tinder and Bumble, on which users can’t message one another at all until both have shown interest in the other. The new OkCupid way won’t be quite so strict—users can still send messages to whomever they want, though those messages will only appear in the recipients’ mailboxes if they indicate that they like the sender—but engineers hope it will help seed more connections while filtering out some messages that will never get a response."

Wednesday, January 17, 2018

Analytic approaches to allocating organs for transplants

Two recent items:

Adapting a Kidney Exchange Algorithm to Align with Human Values
by Rachel Freedman, Jana Schaich Borg, Walter Sinnott-Armstrong, John P. Dickerson, Vincent Conitzer

The  efficient  allocation  of  limited  resources  is  a  classical problem in economics and computer science. In kidney exchanges,  a  central  market  maker  allocates  living  kidney donors to patients in need of an organ. Patients and donors in kidney exchanges are prioritized using ad-hoc weights decided on by committee and then fed into an allocation algorithm that determines who get what—and who does not. In this paper, we provide an end-to-end methodology for estimating weights of individual participant profiles in a kidney exchange.  We first elicit from human subjects a list of patient attributes they consider acceptable for the purpose of prioritizing patients (e.g., medical characteristics, lifestyle choices,and  so  on).  Then,  we  ask  subjects  comparison  queries between  patient  profiles  and  estimate  weights  in  a  principled way from their responses. We show how to use these weights in kidney exchange market clearing algorithms. We then evaluate the impact of the weights in simulations and find that the precise numerical values of the weights we computed matter little, other than the ordering of profiles that they imply.However, compared to not prioritizing patients at all, there is a significant effect, with certain classes of patients being (de)prioritized based on the human-elicited value judgments.


How analytics and machine learning can aid organ transplant decisions
by Dimitris Bertsimas and Nikolaos Trichakis

"MIT Sloan and Massachusetts General Hospital have developed an analytics tool to help doctors in deceased-kidney acceptance decisions. The model aims to calculate the probability of a patient being offered a deceased-donor kidney of a certain quality level within a specific time frame (three, six, or 12 months), given their individual characteristics. Using machine learning, it looks at 10 years of data and millions of prior decisions to estimate a patient’s waiting time in the context of a current active organ offer until the time to the next offer for a higher quality kidney."

Tuesday, January 16, 2018

Welfare effects of limiting the number of interviews by Beyhaghi and Tardos

Here's a new paper on a subject that is coming up in a number of the markets that I keep an eye on:

Effect of Limited Number of Interviews onMatching Markets
by Hedyeh Beyhaghi and Eva Tardos

Abstract. We study outcome of two-sided matching between prospective medical residents who can only apply to a limited number of positions and hospitals who can interview only a limited number of applicants and show non-intuitive effects in the matching outcomes. We study matching size as our notion of efficiency, and show when the number of interviews is limited, a market with limited number of applications achieves a higher efficiency compared to a market with no limit. Also we find that a system of treating all applicants equally (setting the same limit for their number of applications), is more efficient rather than allowing a small set to apply to one more/less position. This comparison results in a scallop-shape figure 2 that shows expected size of matching with respect to expected number of applications. Finally we show that limiting number of interviews does not always hurt efficiency of matching markets and can improve social welfare in certain cases.