Tuesday, August 11, 2020

Transplanting two kidneys from older deceased donors to reduce discards

Here's a venerable but newly fashionable idea in transplantation, particularly for deceased donors whose (individual) kidneys have already been rejected when offered.  Transplant both kidneys into the same recipient, to reduce the risk.

Here's a paper from January:
Lee, K.W., Park, J.B., Cha, S.R. et al. Dual kidney transplantation offers a safe and effective way to use kidneys from deceased donors older than 70 years. BMC Nephrol 21, 3 (2020). https://doi.org/10.1186/s12882-019-1664-8

And here's a very recent news article talking about a different, larger study:

By Melissa J. Webb

"Using data from the United Kingdom Transplant Registry, they identified 7,841 kidneys procured from deceased donors aged 60 years or older, finding that 17% of these were discarded.

Considering the remaining kidneys used for transplant (356 for dual; 5,032 for single), the researchers determined that both donors and recipients of dual transplants were older (median, 73 years vs. 66 years and 64 years vs. 61 years, respectively). Donors of kidneys used in dual transplantation also had higher United States Kidney Donor Risk Indices (2.48 vs 1.98 for those used in single transplants).

After adjusting for confounders, the researchers observed similar 5-year graft survival between dual and single transplants (HR = 0.81), as well as a higher median eGFR at 12 months for recipients of dual transplants (40 mL/min/1.73m2 vs. 36 mL/min/1.73m2)."

Monday, August 10, 2020

Reputation among thieves: ransomware and kidnapping

Like everyone else, I occasionally get notifications of data breaches from organizations with which I have digital relations.  Often the breach involved a third party.  Sometimes the breach involves the theft of data accompanied by a demand of ransom--i.e. the victim is invited to pay the cybercriminal, who then promises to destroy the data instead of selling it on the dark web or otherwise using it.

This bears some resemblance to the kidnapping business, and its high-seas version, piracy.

Here's part of an email I recently received informing me of such a breach, and subsequent payment of ransom.

"I’m writing to inform you that Blackbaud, the company that hosts [xxx’s] relationship management system, suffered a security incident in May. Blackbaud is the world’s largest provider of fundraising technology for non-profits and educational institutions, and many organizations have been impacted by this incident.
"We were also informed by Blackbaud that in order to protect data and mitigate potential identity theft, it met the cybercriminal’s ransomware demand. Blackbaud has advised us that it received assurances from the cybercriminal and third-party experts that the data was destroyed. Blackbaud has been monitoring the web in an effort to verify the data accessed by the cybercriminal has not been misused. "
Why should "assurances from the cybercriminal" be reassuring? (and for how long?).  And what are the roles played by "third-party experts"?

My guess is that, as in the kidnapping biz, intermediaries have emerged to conduct the negotiations, get some sort of assurances, and make it possible for criminal organizations to maintain reputations for honor among thieves.

It is of course possible to regard ransom paying as a repugnant transaction that facilitates ransomware, kidnapping, etc.  In fact the U.S. for some time made it a crime to pay ransom to kidnappers, but relaxed that view over time, as kidnapping became a bigger international business, and there was often a considerable desire (sometimes covered by insurance) to pay ransom when it seemed the best way to recover the kidnapped person alive.

Here are some related posts which touch on that story:

Monday, June 24, 2019  Kidnapping insurance

Tuesday, September 13, 2016 Ransom as a (not so) repugnant transaction

Monday, August 9, 2010 Brokers for pirate ransom

Saturday, December 5, 2009 Market for kidnapping

Sunday, November 30, 2008 Pirate ransom: counterparty risk

Sunday, August 9, 2020

Experimental Economics SITE conference at Stanford, by Zoom, Aug 10 and 11, 2020

 Tomorrow and Tuesday, here's the SITE Experimental Economics conference schedule (Mon Aug. 10 and Tuesday Aug. 11).  

Muriel Introduce SITE confernece
SESSION 1: 9am - 10:30am pacific (12pm eastern, 6pm europe)Lise - in charge
1Overriding in Teams: The Role of Beliefs, Social Image, and GenderMaria Recalde, University of Melbourne(Lise Q)
2Information and the Persistence of the Gender Wage Gap: Early Evidence from California's Salary History BanBenjamin Hansen, University of Oregon(Lise Q)
3Attention as Human CapitalHeather Schofield, University of Pennsylvania(Colin Q)
10:30am - 11am pacific: Break/Discussion (1pm eastern, 7pm europe)
SESSION 2: 11 -12:30pm pacific (2pm eastern, 8pm europe)Muriel - in charge
4Social Learning in Groups: an Experimental StudyMarina Agranov, Caltech(Muriel Q)
5Beliefs in Repeated GamesGuillaume Frechette, NYU(Muriel Q)
6Beyond Ordinal: The Value of Indifferences and Cardinal Information in MatchingClayton Featherstone, University of Pennsylvania(Muriel Q)
12:30pm - 1pm pacific: Break/Discussion (3:30pm eastern, 9:30pm europe)
Day 2 (August 11)
SESSION 3: 9:30am -10:30pm pacific (12:30pm eastern, 6:30pm europe)Lise - in charge
7The Burden of Holding DebtAlejandro Martínez-Marquina, Stanford University
8Claiming Credit: Gender, Memory, and Social NormsJonas Mueller-Gastell, Stanford University
9It’s Not my Fault: Excuse-Seeking Behavior in the Intertemporal DomainMarissa Lepper, University of Pittsburgh
10Do Actions Speak Louder than Motives? Evaluating the Effectiveness of Image-FundraisingPun (pronounced like "Poon") Winichakul, University of Pittsburgh
10:30am - 11am pacific: Break/Discussion (1pm eastern, 7pm europe)
SESSION 4: 11 -12:30pm pacific (2pm eastern, 8pm europe)Muriel - in charge
11Fairness Across the World: Preferences and BeliefsAlexander W. Cappelen, Norwegian School of Economics(Christine Q)
12Cognitive Flexibility or Moral Commitment? Evidence of Anticipated Belief Distortion
Silvia Saccardo, Carnegie Mellon University(Christine Q)
13Digital AddictionHunt Allcott, New York University and Microsoft Research(Colin Q)
Muriel close SITE confernece
12:30pm - 1pm pacific: Break/Discussion (3:30pm eastern, 9:30pm europe)

Saturday, August 8, 2020

Is convalescent plasma useful for treating covid-19?

The reported results on convalescent plasma are so far still quite incomplete, and mixed.  If I had to summarize, I'd say that a growing body of evidence suggests that treating early stage (e.g. just hospitalized) covid-19 patients increases and speeds the chance of recovery, while there is little convincing evidence that convalescent plasma helps more severely ill patients who have begun to have serious complications.

Here is a recent WSJ article:

By Amy Dockser Marcus

"Hospitalized Covid-19 patients who received transfusions of blood plasma rich with antibodies from recovered patients reduced their mortality rate by about 50%, according to researchers running a large national study.
"The researchers said they saw signs that the treatment might be working in patients who received high levels of antibodies in plasma early in the course of their illness. They based their conclusions on an analysis of about 3,000 patients."

Here's a recent paper in JAMA on a very small randomized trial in China that doesn't find statistically significant effects on patients who 

August 4, 2020
Ling Li, MD, PhD; Wei Zhang, MD; Yu Hu, MD, PhD; Xunliang Tong, MD, PhD; Shangen Zheng, MD; Juntao Yang, PhD; Yujie Kong, MD; Lili Ren, PhD; Qing Wei, MD; Heng Mei, MD, PhD; Caiying Hu, MD; Cuihua Tao, MD; Ru Yang, MD; Jue Wang, MD; Yongpei Yu, PhD; Yong Guo, PhD; Xiaoxiong Wu, MD; Zhihua Xu, MD; Li Zeng, MD; Nian Xiong, MD, PhD; Lifeng Chen, MD; Juan Wang, MD; Ning Man, MD; Yu Liu, PhD; Haixia Xu, MD; E. Deng, MS; Xuejun Zhang, MS; Chenyue Li, MD; Conghui Wang, PhD; Shisheng Su, PhD; Linqi Zhang, PhD; Jianwei Wang, PhD; Yanyun Wu, MD, PhD; Zhong Liu, MD, PhD
  JAMA. 2020; 324(5):460-470. doi: 10.1001/jama.2020.10044

Abstract: This randomized trial compares the effects of convalescent plasma therapy with standard care vs standard care alone on time to clinical improvement among patients with severe or life-threatening COVID-19 disease in China.

"Among patients with severe or life-threatening COVID-19, convalescent plasma therapy added to standard treatment did not significantly improve the time to clinical improvement within 28 days, although the trial was terminated early and may have been underpowered to detect a clinically important difference."

My last donation had high enough antibodies to qualify me for another: I hope these are going to patients for whom they will be useful.

Friday, August 7, 2020

Global kidney exchange between Abu Dhabi and Kerala (India)

Here is an article in the newspaper Malayalam Manorama, in Malayalam, the language spoken in Kerala, about a global kidney exchange between hospitals in Abu Dhabi in the United Arab Emirates, and in Kerala in India.

The url hints at the story: the exchange was between a Kerala hospital and a UAE hospital that both used kidney exchange software provided by Mike Rees's organization, the Alliance for Paired Kidney Donation (APKD), to identify the exchange, which was performed in India:

The article says SEHA Kidney Care Staff( Anan Purushothaman, Sheenamma Varghese , Siddiq Anwar) with Dr Mike Rees from Alliance For Paired Donation helped find a compatible  kidney donor in India via the “Global Kidney Paired Exchange”. Dr Feroz Aziz then successfully transplanted the two pairs.

Kim Krawiec, through a friend fluent in Malayalam, gives the following summary:

"The article goes on to say that Najla was in want of a kidney donor. Even though she had 3 of her relatives who were ready to donate none of them were compatible. She was asked to get in touch with the organisation called Alliance for Paired Kidney Donation, where they find donors all around the world using the latest technology. With the help of this organisation and the latest technology, not to mention the doctors and nurses she was able to find a compatible donor. At the same time Najma's mother was able to donate her kidney to the Abu Dhabi donor's husband. Now all are well and back to normal life."

Thursday, August 6, 2020

Is randomization repugnant?

Patrick R. Heck,  Christopher F. Chabris,  Duncan J. Watts, and Michelle N. Meyer
PNAS first published July 27, 2020 https://doi.org/10.1073/pnas.2009030117
Edited by Margaret Levi, Stanford University, Stanford, CA, and approved July 4, 2020 (received for review May 13, 2020)
Abstract: We resolve a controversy over two competing hypotheses about why people object to randomized experiments: 1) People unsurprisingly object to experiments only when they object to a policy or treatment the experiment contains, or 2) people can paradoxically object to experiments even when they approve of implementing either condition for everyone. Using multiple measures of preference and test criteria in five preregistered within-subjects studies with 1,955 participants, we find that people often disapprove of experiments involving randomization despite approving of the policies or treatments to be tested.

Wednesday, August 5, 2020

Admissions to polytechnics in Finland, by Kristian Koerselman

Here's a paper that gives a very clear description of the centralized application process for Finnish polytechnics (applied universities), which gives applicants a complicated strategic problem, and results in many applicants re-applying in subsequent years.

Assignments are by a (school proposing) deferred acceptance algorithm, but applicants get extra points in a school's preferences by listing it first, they can only list four programs, and they must choose which exams to take.

Why Finnish polytechnics reject top applicants
Kristian Koerselman
Education Economics, July 2020

"The Finnish polytechnic assignment provides us with an example where applicants are asked to strategize in their applications while having poor prior information on the set of programs that would admit them. These features should in and of themselves already be expected to cause a poor assignment outcome. I highlight the additional role which entrance exams appear to play in creating what should arguably be seen as a misrepresentation of true admission criteria analogous to a misrepresentation of applicants' true preferences. Because applicants take and retake different entrance exams in different years, programs rank the same applicants differently in different years, giving applicants an incentive to reapply even if they were originally assigned to their within-year most preferred feasible program.
"Finland provides 9 years of compulsory, comprehensive education, after which almost all students continue in approximately equal proportions to either an academically-oriented high school or to a vocational school. High school concludes with a set of nationally standardized and externally graded matriculation exams. Though students have a reasonable amount of freedom in choosing the subjects they want to take an exam in, they have to take into account that different higher education programs value matriculation exam grades in different subjects differently.

Higher education is provided by polytechnics, also called universities of applied sciences, and by universities. The former mainly offer bachelor programs, and the latter mainly combined bachelor/master programs. About half of each birth cohort ever enrolls in higher education, with total yearly admissions somewhat larger at polytechnics than at universities. Although it is not uncommon for vocational school graduates to apply to a polytechnic, high school graduates are the largest group of polytechnic applicants.
"Higher education applications are extremely competitive, with for example only about one-third of polytechnic applicants being admitted nationally each year. Rejected applicants are likely to reapply, often multiple years, and even admitted applicants often reapply. Re-applications are an important reason why the numbers of applicants per seat are so large. Applicants effectively queue into higher education, likely causing them to be admitted at an unnecessarily old age, and therefore also to graduate at an unnecessarily old age. The 2011 polytechnic applicants on which this study is based for example had on average graduated from high school already two and a half years earlier, and many of them would be older still when they were finally admitted to the higher education program they would eventually graduate from.

"All higher education applications are made to a national clearinghouse. Polytechnic admission decisions are generally made centrally by the clearinghouse itself, while university admission decisions are generally not. In this paper, I analyze the 2011 centralized assignment of high school graduates to Finnish polytechnics. In total, 50,894 high school graduates applied to 16,655 seats in 440 programs, divided over 8 fields.

"The application process starts in March, when applicants can apply to up to four programs in order of preference. Applicants must then choose which entrance exams to prepare for and take, typically in May or June. After the entrance exams have been graded, an admission score is calculated for each application. This score is mainly based on applicants' matriculation exam grade point averages and entrance exam results. The weights assigned to different matriculation exam subjects are typically shared within each field, and entrance exams tend to be shared as well. Extra points are awarded for the first listed choice, as well as for factors like relevant labor market experience. The relative weight of the different admission score components in determining the admission score can be seen in Table 2.

"Based on their submitted preference ordering and on their admission scores, applicants are assigned to programs through a centrally run program-proposing deferred acceptance algorithm, each applicant either being admitted to a single program or not being assigned at all. Admitted applicants then either accept their seat or reject it. A much smaller second round of offers is sent out by the programs themselves to make up for first-round rejections. The second round of the process ends at the start of the fall term in September.
"Applicants have multiple reasons to strategize in choosing which programs to apply to. Among others, the fact that applicants receive extra points for their first listed choice implies that they will want to list a program first where they have a chance to actually be admitted. Similarly, the four-program limitation means not only that there may be programs acceptable to the applicant which the applicant is not allowed to list, but also that the applicant will need to use the four allowed applications wisely. Third, the applicant faces a strategic choice in which entrance exams to prepare for and take, typically concentrating all effort on a single application. Fourth, the use of a program-proposing algorithm may in and of itself already give applicants an incentive to strategize."
"Though applicants receive good indications of their matriculation exam grades before they apply, and may be aware of previous years' admission score cut-offs, they however necessarily learn their entrance exam scores only after choosing where to apply and which entrance exams to take, adding a considerable degree of uncertainty to their application.
"When classifying applicants into thirds based on their program-specific matriculation exam GPA, as many as 54% of top third applicants remain unassigned anywhere. Even using the actual admission score, 34% of top third applicants remain unassigned.
"Even if applicants do apply to more than one program, their admission chances are relatively low for programs listed second, third and fourth, with the probability of being assigned to a program being 27% for the program listed first, but only between 3 and 4 per cent for programs listed lower. This is partly due to the extra points given for the first listed program, but is probably also related to applicants' strategic choices on which entrance exams to take. "