Obstacles facing liver exchange

 Liver exchange is different than kidney exchange in a number of important dimensions, some of which will present obstacles that need to be overcome in different ways. (Although it looks like in liver exchange the donors will travel to the recipients instead of having the organs shipped, as is now mostly done in U.S. kidney exchange.  That's actually how kidney exchange worked when it began) Here's a recent article from Medscape:

Can a Nationwide Liver Paired Donation Program Work?  by Lucy Hicks

"To expand the number of living liver donations in the United States, the United Network for Organ Sharing (UNOS) has launched the first national paired liver donation pilot program in the United States.

...

"In 2020, 1095 people died while waiting for a liver transplant

...

"Paired kidney donation programs have been running since 2002, but paired liver donation is relatively new. Since the first US living-donor liver transplant in 1989, the procedure has become safer and is a viable alternative to deceased liver donation. A growing number of living donor programs are popping up at transplant centers across the country.

"Still, living-donor liver donation makes up a small percentage of the liver transplants that are performed every year. In 2022, 603 living-donor liver transplants were performed in the United States, compared to 8925 liver transplants from deceased donors

...

"There are several notable differences between living donor kidney transplants and living donor liver transplants. For example, living donor liver transplant is a more complicated surgery and poses greater risk to the donor. According to the OPTN 2020 Annual Report, from 2015–2019, the rehospitalization rate for living liver donors was twice that of living kidney donors up to 6 weeks after transplant (4.7% vs 2.4%). One year post transplant, the cumulative rehospitalization rate was 11.0% for living liver donors and 4.8% for living kidney donors.

"The risk of dying because of living donation is also higher for liver donors compared to kidney donors. The National Kidney Association states that the odds of dying during kidney donation are about 3 in 100,000, while estimates for risk of death for living liver donors range from 1 in 500 to 1 in 1000. But some of these estimates are from 10 or more years ago, and outcomes have likely improved

...

"In addition to a more complex surgery, surgeons also have a smaller time window in which to transplant a liver than than they do to transplant a kidney. A kidney can remain viable in cold storage for 24–36 hours, and it can be transported via commercial airlines cross country. Livers have to be transplanted within 8–12 hours, according to the OPTN website. For living donation, the graft needs to be transplanted within about 4 hours, Samstein noted; this poses a logistical challenge for a national organ paired donation program.

"We worked around that with the idea that we would move the donor rather than the organ," he said. The program will require a donor (and a support person) to travel to the recipient's transplant center where the surgery will be performed. While 3 of the 15 pilot paired donation transplant centers are in New York City, the other programs are scattered across the country, meaning a donor may have to fly to a different city to undergo surgery.

"Including the preoperative evaluation, meeting the surgical team, the surgery itself, and follow-up, the donor could stay for about a month. The program offers up to $10,000 of financial assistance for travel expenses (for both the donor and support person), as well as lost wages and dependent care (for the donor only). Health insurance coverage will also be provided by the pilot program, in partnership with the American Foundation for Donation and Transplant.

...

"The 1-year pilot program is set to begin when the program conducts its first match run — an algorithm will help match pairs who are enrolled in the program. About five to seven enrolled pairs would be ideal for the first match run, a UNOS spokesperson said. It is possible that the 1-year pilot program could run without performing any paired transplants, but that's unlikely if multiple pairs are enrolled in the system, the spokesperson said. At the time of this story's publication, the one enrolled pair are a mother and daughter who are registered at the UCHealth Transplant Center in Colorado."

"It Is Time for Interventional Cardiology Fellowship to Join the National Resident Matching Program," say its leaders

 The current appointment process for interventional cardiology fellows is early and congested, and programs feel obliged to make exploding offers, often to internal candidates, without much opportunity for external candidates and programs to become acquainted. In short, they are facing the problems with decentralized hiring that have led many medical specialties to use a centralized match to organize the labor market for residencies and fellowships.  Here's a proposal that this fellowship program should join the Match in order to have a more orderly, better informed process.

Vallabhajosyula, Saraschandra, Sabeeda Kadavath, Alexander G. Truesdell, Michael N. Young, Wayne B. Batchelor, Frederick G. Welt, Ajay J. Kirtane, Anna E. Bortnick, and ACC Interventional Section Leadership Council. "It Is Time for Interventional Cardiology Fellowship to Join the National Resident Matching Program." Cardiovascular Interventions 15, no. 17 (2022): 1762-1767.

"In this perspective article, which is a summation of the deliberations of the American College of Cardiology Interventional Section Leadership Council, we describe the current process of interventional cardiology fellowship candidate selection and opportunities for improvement by joining the Match.

...

"Current Application Process

...

"the date for program review of applications starts on December 1st (1½ years before the start of the interventional cardiology training program to which applicants are applying), although programs are free to offer spots earlier. At the time applications are submitted, cardiovascular medicine fellows in traditional 3-year programs have variable exposure to the cardiac catheterization laboratory. In our experience, for many applicants, the timing of the application process precludes an adequate diagnostic catheterization laboratory experience in order to inform decision-making. ... program leadership is heavily reliant on candidate performance in the interview and on subjective evaluation through letters of recommendation from faculty mentors who have typically had a single year of exposure to applicants.

Designing queues for overloaded waiting lists, by Jacob Leshno

 Here's a paper by Jacob Leshno, with a really creative new contribution to the (venerable) queuing literature. 

Leshno, Jacob D. 2022. "Dynamic Matching in Overloaded Waiting Lists." American Economic Review, December, 112 (12): 3876-3910. DOI: 10.1257/aer.20201111 (ungated working paper link here)

"Abstract: This paper introduces a stylized model to capture distinctive features of waiting list allocation mechanisms. First, agents choose among items with associated expected wait times. Waiting times serve a similar role to that of monetary prices in directing agents' choices and rationing items. Second, the expected wait for an item is endogenously determined and randomly fluctuates over time. We evaluate welfare under these endogenously determined waiting times and find that waiting time fluctuations lead to misallocation and welfare loss. A simple randomized assignment policy can reduce misallocation and increase welfare."

"A practical recommendation is the simple service-in-random order (SIRO) queuing policy. A SIRO buffer-queue mechanism has a simple description: agents who decline an item are allowed to join a priority pool for their preferred item, and agents in each priority pool have an equal probability of receiving an arriving item. We characterize the SIRO buffer-queue mechanism as the robustly optimal mechanism. This simple randomization does not fully equalize the expected wait across states, but it lessens the expected wait fluctuations and therefore reduces the misallocation probability and achieves higher welfare in equilibrium than FCFS." [FCFS= first come first served.]

"In summary, this paper offers two messages for the practical design of allocation through waiting lists. First, although many public-housing authorities have waiting list policies that discourage applicants from declining items, the analysis suggests agents should be encouraged to decline mismatched items. When the system is overloaded, an agent who declines a mismatched item allows the system to search further and assign the item to a matching agent. Furthermore, such an agent reduces the waiting costs of others by allowing them to be assigned before him. Second, equalizing the expected wait agents face when making their choice can improve welfare. This can be achieved by the SIRO buffer-queue mechanism or by partial information mechanisms. Both are practical mechanisms that offer agents more equal options at the time they make their choice, and thus reduce misallocation and improve welfare."

Roundabouts

 A straight line isn't always the safest path between two points.

The Washington Post has the story:

Roundabouts are (slowly!) eating the suburbs by Andrew Van Dam

"Compared with the hundreds of thousands of normal intersections peppering the American landscape, ruled by stop signs and traffic lights, roundabouts are rare beasts. But unlike the drivers they frequently confuse and bedevil, roundabouts are coming on fast.

...

"The modern roundabout relies on a geometric design that forces traffic to slow, plus a simple innovation born in 1960s Britain: the rule that people already in the circle get the right of way. In traditional rotaries and traffic circles, which still lurk in many East Coast cities, traffic moves faster and vehicles already in the circle often must yield to newcomers.

...

"Why add a roundabout, you might ask. Because roundabouts offer impressive safety gains. In general, a roundabout will drive down fatal crashes by 90 percent and cut all car-crash injuries by at least 75 percent, even while accommodating a higher volume of cars.

"At a rural two-way stop, the gains can be even more dramatic. A roundabout can slash all traffic injuries, both fatal and nonfatal, by almost 90 percent. After all, it’s almost impossible to blow through a roundabout at 60 miles an hour and T-bone a minivan — an all-too-common occurrence in typical rural intersections.

“That’s the beauty of the roundabout,” Rodegerdts told us. “It’s the geometry. It’s the curves that are doing the work. And not relying on a traffic-control device as the sole thing keeping you from colliding at high speed.”

***********

Nevertheless...here's a related NYT story:

The Exceptionally American Problem of Rising Roadway Deaths

Why other rich nations have surpassed the U.S. in protecting pedestrians, cyclists and motorists. By Emily Badger and Alicia Parlapiano

"In 2021, nearly 43,000 people died on American roads, the government estimates. And the recent rise in fatalities has been particularly pronounced among those the government classifies as most vulnerable — cyclists, motorcyclists, pedestrians.

...

"In the 1990s, per capita roadway fatalities across developed countries were significantly higher than today. And they were higher in South Korea, New Zealand and Belgium than in the U.S. Then a revolution in car safety brought more seatbelt usage, standard-issue airbags and safer car frames, said Yonah Freemark, a researcher at the Urban Institute.

"Fatalities fell as a result, in the U.S. and internationally. But as cars grew safer for the people inside them, the U.S. didn’t progress as other countries did to prioritizing the safety of people outside them.

“Other countries started to take seriously pedestrian and cyclist injuries in the 2000s — and started making that a priority in both vehicle design and street design — in a way that has never been committed to in the United States,” Mr. Freemark said.

"Other developed countries lowered speed limits and built more protected bike lanes. They moved faster in making standard in-vehicle technology like automatic braking systems that detect pedestrians, and vehicle hoods that are less deadly to them. They designed roundabouts that reduce the danger at intersections, where fatalities disproportionately occur.

"In the U.S. in the past two decades, by contrast, vehicles have grown significantly bigger and thus deadlier to the people they hit. Many states curb the ability of local governments to set lower speed limits. The five-star federal safety rating that consumers can look for when buying a car today doesn’t take into consideration what that car might do to pedestrians."

Improving the transition to (surgical) residency

The transition from medical school to residency is presently troubled by congestion involving (too) many applications and interviews.  It's a subject of considerable discussion in the medical community, sometimes hampered between the parts of the process that proceed the Match, and the Match itself (which is the clearinghouse run by the NRMP that, after all applications and interviews have been processed, solicits rank order lists and turns them into a matching of doctors to residency programs)..  Here's a paper that focuses sensibly on the runup to the Match, even though its title follows the (unfortunately common) practice of calling the whole process the Match.

Designing the “match of the future”: challenges and proposed solutions in the interview and match phase of the UME–GME transition by Sophia K. McKinley, Maria S. Altieri, Olabisi Sheppard, Kimberly Hendershot, Keneeshia Williams, Brigitte K. Smith on behalf of the ASE Graduate Surgical Education Committee, Global Surgical Education - Journal of the Association for Surgical Education : 17 November

Table 1 Challenges and proposed solutions in the surgical resident selection process (click to embiggen)

Limiting congestion by limiting applications, or making them costly

 Here's a paper that investigates two alternatives to limiting congestion in college admissions: one is to limit applications, and the other is to add a small cost for each additional application. (This is a current topic of discussion in a number of other applications, including matching of new doctors to residencies.)

Application Costs and Congestion in Matching Markets by YingHua He and Thierry Magnac, The Economic Journal,  https://doi.org/10.1093/ej/ueac038 (online early)

Abstract: "A matching market often requires recruiting agents, or ‘programmes’, to costly screen ‘applicants’, and congestion increases with the number of applicants to be screened. We investigate the role of application costs: higher costs reduce congestion by discouraging applicants from applying to certain programmes; however, they may harm match quality. In a multiple-elicitation experiment conducted in a real-life matching market, we implement variants of the Gale-Shapley deferred-acceptance mechanism with different application costs. Our experimental and structural estimates show that a (low) application cost effectively reduces congestion without harming match quality."

"Our empirical strategy is novel. It begins with a multiple-elicitation field experiment that enables us to directly evaluate the effects of application costs. The experiment involves the real-life matching of 129 applicants to the seven master’s programmes at the Toulouse School of Economics (TSE), and was conducted in May 2013 for admission in the 2013–4 academic year. The experimental market designs are three variants of the Gale-Shapley deferred-acceptance (DA) mechanism encountered in practice: the traditional DA mechanism, under which applicants can apply to all programmes without any cost; the DA mechanism with truncation (DA-T), under which applicants can apply to no more than four programmes (hence, DA-T-4); and the DA mechanism with cost (DA-C), under which applicants must write a motivation letter for each additional application beyond the first three applications. Under each mechanism, every applicant is required to submit a rank-ordered list of programmes (ROL). As applicants are informed that one of the mechanisms will be implemented, they have incentives to behave optimally under each mechanism.

"To evaluate the performance of a matching procedure, we focus on two dimensions of a matching outcome: the congestion and match quality. The former is measured by screening costs and approximated by the number of applicants to screen; the latter is measured by the welfare of both sides, the number of unmatched applicants, as well as the number of blocking pairs. A pair comprising applicant and programme blocks a matching if both would be better off by being matched together after leaving their current matches. The stability of a matching, defined as the absence of any blocking pair, is the key to the success of matching markets (Roth, 1991). Importantly, stability implies Pareto efficiency when both sides are endowed with strict preferences (Abdulkadiroğlu and Sönmez, 2013)."

The past and future of the transition from medical school to residency, in the Journal of Graduate Medical Education, by Williamson, Soane, and Carmody

 The October issue of the Journal of Graduate Medical Education considers the past and future of the transition to residency.

The US Residency Match at 70: What Was, What Is, and What Could Be  by Edwin Williamson, MD; Caroline Soane, BA; J. Bryan Carmody, MD, MPH, J Grad Med Educ (2022) 14 (5): 519–521., https://doi.org/10.4300/JGME-D-22-00248.1

"But while early offers are long gone, the residency selection process now faces a new set of challenges related to the increasing number of applications submitted by contemporary applicants. In 2020 the average US medical school graduate submitted 70 residency applications.9  The average for some specialties is even higher. For instance, in 2022, the average osteopathic medical school applicant in obstetrics and gynecology submitted 85 applications, while US MD applicants in orthopedic surgery submitted 96 applications, and international medical graduates submitted 100 applications each to internal medicine programs.10  This overapplication increases costs for applicants and programs, leads to reliance on convenient screening metrics in applicant evaluation, and does not ultimately improve Match rates.9 "

Coordinating the timing of the market for new Economics Ph.D.s: guidance from the AEA

 Here's an email broadcast by the American Economic Association, aimed to promote market thickness by avoiding unraveling and dealing with congestion:

AEA Guidance on Timeline for 2022-23 Economics Job Cycle

 July 1, 2022

To: Members of the American Economic Association
From: Peter L. Rousseau, Secretary-Treasurer
Subject: AEA Guidance on Timeline for 2022-23 Economics Job Cycle

The AEA Executive Committee, in conjunction with its Committee on the Job Market, recognizes that it is to the benefit of the profession if the job market for economists is thick, with many employers and job candidates participating in the same stages at the same time.  Moreover, the AEA's goals of diversity, equity, and inclusion are fostered by having a timeline that remains widely known and accepted, ensuring that candidates can correctly anticipate when each stage will occur. With these goals in mind, and in light of inquiries from both students and departments about how to proceed, the AEA asks that departments and other employers consider the following timeline for initial interviews and “flyouts” in the upcoming job cycle (2022-23).  

Interview invitations
The AEA suggests that employers wait to extend interview invitations until the day after job market signals are transmitted to employers.

Rationale: the AEA created the signaling mechanism to reduce the problem of asymmetric information and allow job candidates to credibly signal their interest to two employers. The AEA asks that employers wait to extend interview invitations until those signals have been transmitted, and to use that information to finalize their set of candidates to interview. This helps the job market in several ways: it reduces the problem of imperfect information, it helps ensure a thick market at each stage, and it promotes the AEA’s goals of diversity, equity, and inclusion. Job candidates from historically under-represented groups may lack informal networks and thus may especially rely on the signals to convey their interest. Waiting to review the signals before issuing invitations promotes a fairer, more equitable process.

We also ask that all employers indicate on EconTrack when they have extended interview invitations; this allows candidates to learn about the status of searches without visiting websites posting crowd-sourced information and potentially inappropriate other content.

Interviews
The AEA recommends that employers conduct initial interviews starting on Monday, January 2, 2023, and strongly recommends that all interviews take place virtually (e.g. by Zoom). We suggest that interviews not take place during the AEA meeting itself (January 6-8, 2023).

Rationale: In the past, interviews were conducted in person at the AEA/ASSA meetings. This promoted thickness of the market, because most candidates and employers were present at the in-person meetings, but had the disadvantage of precluding both job candidates and interviewers from fully participating in AEA/ASSA sessions. 

Interviews should now be conducted virtually to prevent risk of exposure to COVID, and to promote equity among the candidates. Informal feedback to the AEA committee on the job market indicated that the benefits of virtual first-round interviews (e.g. low monetary cost, zero cost in travel time, convenience) outweighed the limitations (e.g. less rich interaction).

We recommend that employers wait until January 2 to interview candidates because job candidates may have teaching or TA responsibilities in December. Moreover, having a clear start date for interviews will help candidates to have accurate expectations of the timing of the stages of the market. An unraveling of the market works against the AEA’s goal of having a thick market at each stage and also works against candidates having uniform expectations of the timing of each stage of the market.

We ask that interviews NOT take place during the AEA/ASSA meetings (January 6-8, 2023) in order to allow job candidates and interviewers to participate in the conference.

Flyouts and offers
Flyouts and offers have historically happened at times appropriate for the employer, and the AEA sees no reason to suggest otherwise.  We ask that all employers indicate on EconTrack when they have extended flyout invitations and closed their searches. Unlike with interviews, the AEA does not take a position on whether flyouts should be virtual or in-person.

Job market institutions and mechanisms
Please keep in mind the various job market institutions and mechanisms created by the AEA to improve the job market:

·       The JOE Network includes a database of job openings for economists.

o   Employers may sign up here: https://www.aeaweb.org/joe/employer.

o   Job candidates may search the database here: https://www.aeaweb.org/joe/listings.

o   The JOE Network has an electronic clearinghouse for job candidates to submit job applications. Job candidates may register here: https://www.aeaweb.org/joe/candidate.

·       The AEA Committee on the Job Market releases data and guidance on the job market here: https://www.aeaweb.org/joe/communications.

·       EconTrack: a board on which employers can indicate when they have extended interview and flyout invitations, and closed their search: https://www.aeaweb.org/econtrack.

Thank you for helping to ensure a transparent and equitable job market for new Ph.D. economists.  

Signaling for Otolaryngology residency programs

 Here's a report on the use of signaling for residency positions, from the Oto match.

Pletcher, Steven, Chang, C.W., Thorne, Marc, MD, MPH & Malekzadeh, Sonya. (2022). The Otolaryngology Residency Program Preference Signaling Experience. Academic Medicine, 97, 664-668. https://doi.org/10.1097/ACM.0000000000004441

"The average applicant to Otolaryngology-Head and Neck Surgery in the 2021 residency application cycle applied to more than 50% of otolaryngology programs nationwide, submitting 77 applications, 1 a 34% increase over 5 years. 2 This surge has made it difficult for residency programs to holistically review applications and has limited opportunities for applicants to stand out to programs of particular interest.

...

"A formal preference signaling process provides all applicants with access to a known and stable quantity of signals. Through this process, at the time of application submission, students send a signal to indicate to a defined number of residency programs their particular interest in those programs. Such signals allow students to stand out to their favored programs and allow programs to receive a list of highly interested applicants. To our knowledge, this approach has not been used previously in the residency application process. Yet, articles advocating for signaling exist in the otolaryngology literature, 5-7 and the methodology, rationale, and results of preference signaling for graduates of economics PhD programs applying for faculty positions have been described. 8

"An OPDO working group, comprising the 4 authors, drove the establishment of a signaling process. In the spring of 2020, we held a series of meetings and webinars to engage stakeholders in the development and implementation of a signaling process. We included students, program directors, and specialty societies, such as the Society of University Otolaryngologists and the Association of Academic Departments of Otolaryngology Otolaryngology Chairs Organization. Additional discussions with the Association of American Medical Colleges, the Electronic Residency Application Service (ERAS), and the National Resident Matching Program also took place.

"In hindsight, establishing consensus across stakeholders proved to be the most challenging hurdle to successful implementation of our signaling process. Stakeholders had to accept this change and the inherent risks of implementing a "never before in medicine" process. These discussions, however, also provided a critical opportunity to refine our proposal and create an educational ecosystem that accepted this signaling process.

...

"All otolaryngology residency programs attested to the code of conduct, and none opted out of the signaling process. By October 21, 2020, the date that applications were released to programs, 611 students had submitted applications to otolaryngology residency programs, 559 applicants had submitted a Match list including an otolaryngology program, and 558 applicants had participated in the signaling process. Of 119 non-military otolaryngology residency programs, 118 received at least 1 signal. The number of signals received per program ranged from 0 to 71 with a mean of 22 (standard deviation 17) and a median of 16 

...

"Program directors most commonly reported using signals as a tiebreaker for similar applications and as part of an initial application review algorithm. One program required a signal to offer an applicant an interview.

...

"Applicants reported applying to a mean of 77 programs (standard deviation 21), including their 5 signaled programs. The rate of receiving an interview offer was significantly higher for signaled programs (58%, 670/1,150) compared with both nonsignaled programs (14%, 2,394/16,520; P < .001) and the comparative nonsignal program (23%, 53/230; P < .001; see Figure 2). To assess the impact of signaling across the spectrum of applicant competitiveness, we divided applicants into quartiles based on their overall likelihood of receiving an interview offer. Signals had a significant impact (P < .001) on interview offers across all quartiles (see Figure 3).

...

"The magnitude of signal impact we found likely represents both an increased rate of interview offers from signaled programs and a decreased rate of interview offers from nonsignaled programs. In contrast to our 5 signals, the American Economic Association provides 2 signals for graduates of economics PhD programs applying for faculty positions, suggesting that signal scarcity preserves its value and intent. 8 Decreasing the number of signals would force applicants to narrow their list of programs of primary interest and would disincentivize signaling "dream" programs. By increasing the number of signals, the lack of a signal becomes an indication of disinterest. If enough signals are provided, signaling could have a similar impact on the application process as an application cap. The ideal number of signals then must be explored.

"Our data demonstrated that signaling allowed applicants to influence their likelihood of receiving an interview offer from programs of particular interest. Given the distribution of signals received across programs, we believe that signaling also improved the distribution of interview offers among applicants, which could mitigate interview hoarding. 

...

"While applicants appear to benefit significantly from signaling, they also bear the responsibility of targeting their signals appropriately.

...

"Multiple specialties have expressed interest in adopting a similar program. However, otolaryngology is not representative of all medical or surgical specialties. It is a small, competitive surgical subspecialty with a 63% Match rate and no unmatched residency slots in the 2021 cycle. While the impact of signaling may vary significantly outside of these parameters, we are optimistic that the benefits will carry over to other specialties. Incorporating a signaling option within ERAS would facilitate both wide adoption and further analysis of such a process."

Queuing for ridesharing and organ allocation

 Queues for ridesharing drivers at airports (where some trips are much better than others) lead to lots of rejected trips by those at the head of the line, while they wait for a good one.  This is of course something that also occurs in deceased donor waiting lists.

Here's a paper that tackles the ridesharing problem:

Randomized FIFO Mechanisms by Francisco Castro, Hongyao Ma, Hamid Nazerzadeh, Chiwei Yan

Abstract: "We study the matching of jobs to workers in a queue, e.g. a ridesharing platform dispatching drivers to pick up riders at an airport. Under FIFO dispatching, the heterogeneity in trip earnings incentivizes drivers to cherry-pick, increasing riders' waiting time for a match and resulting in a loss of efficiency and reliability. We first present the direct FIFO mechanism, which offers lower-earning trips to drivers further down the queue. The option to skip the rest of the line incentivizes drivers to accept all dispatches, but the mechanism would be considered unfair since drivers closer to the head of the queue may have lower priority for trips to certain destinations. To avoid the use of unfair dispatch rules, we introduce a family of randomized FIFO mechanisms, which send declined trips gradually down the queue in a randomized manner. We prove that a randomized FIFO mechanism achieves the first best throughput and the second best revenue in equilibrium. Extensive counterfactual simulations using data from the City of Chicago demonstrate substantial improvements of revenue and throughput, highlighting the effectiveness of using waiting times to align incentives and reduce the variability in driver earnings."

"Many ridesharing platforms now maintain virtual queues at airports for drivers who are waiting in  designated  areas,  and  dispatch  drivers  from  the  queue  in  a  first-in-first-out  (FIFO)  manner.4 This resolves the congestion issues and is also considered more fair by many since drivers who havewaited the longest in the queue are now the first in line to receive trip offers.  At major U.S. airports,however, a driver at the head of the queue will receive the next trip offer in a few seconds under FIFO dispatching, if she declines an offer from the platform (see Figure 12).  As we shall see, thislowered cost of cherry-picking substantially exacerbates existing problems on incentive alignment.

...

"During busy hours, instead of accepting an average trip, drivers who are close to the head of the queue are better off declining most trip offers and waiting for only the highest earning trips.  Riders, however, have finite patience, despite being willing to wait for some time for a match.  When each driver decline takes an average of 10 seconds, 2 minutes had passed after a trip with low or moderate earnings (e.g.  trips to downtown Chicago) was offered to and declined by the top 12 drivers in the queue.5 At this point, it is very likely that the rider cancels her trip request, not knowing when a driver will be assigned, if at all.

...

"To  achieve  optimal  throughput  and  revenue  without  the  use  of  an  unfair  dispatch  rule,  weintroduce a family ofrandomized FIFO mechanisms.  A randomized FIFO mechanism is specifiedby a set of “bins” in the queue (e.g., the top 10 positions, the 10th to 20th positions, and so on).Each trip request is first offered to a driver in the first bin uniformly at random.  After each decline, the mechanism then offers the trip to a random driver in the next bin.  By sending trips gradually down the queue in this randomized manner, the randomized FIFO mechanisms appropriately align incentives using waiting times,  achieving the first best throughput and second best net revenue: the option to skip the rest of the line incentivizes drivers further down the queue to accept trips with  lower  earnings;  randomizing  each  dispatch  among  a  small  group  of  drivers  increases  each individual driver’s waiting time for the next dispatch, thereby allowing the mechanism to prioritize drivers closer to the head of the queue for trips to every destination without creating incentives for excessive cherry-picking."

Is applying to college too hard?

 While there are concerns that electronic application services like the common app have led to an explosion of applications, there are also concerns in the opposite direction, that applying to college remains a barrier particularly to students who don't automatically think of college as an option.

Here's a story from the Chronicle of Higher Ed about an initiative to ease the application process.

Rethinking the Act of Applying to College. A tedious process that puts the onus on students may need an overhaul.  By Eric Hoover

"On Thursday, the Coalition for College, a membership group of 162 institutions with a shared online application, announced a plan to ease the challenge of applying. As part of a new partnership, the organization will embed its application process into Scoir, an online college-advising platform used by students at more than 2,000 high schools nationwide.

"Instead of creating a Coalition application and typing information into a separate website, students with a Scoir account will soon be able to apply to any Coalition college by transmitting an admission form prepopulated with information — demographic data, grades, test scores, and so on — that would already reside under the same virtual roof.

...

"The more complex the application process, the less equitable it becomes."

"That was a key line from a report published in January by the National Association for College Admission Counseling and the National Association of Student Financial Aid Administrators. The report, which imagined what the college-application process would look like if racial equity were the main objective, included findings and recommendations drawn from interviews with a panel of admissions and financial-aid experts, as well as students."

An Interview Match for medical residents and fellows--a preliminary proposal

 There is a lot of concern in the graduate medical education community that too much time and treasure is being spent on too many unproductive interviews prior to the submission of rank order lists for the Match.  Here's discussion of a proposal for an interview match, to precede the interview stage before the actual NRMP Match.

Explaining a Potential Interview Match for Graduate Medical Education, by Irene Wapnir, MD; Itai Ashlagi, PhD; Alvin E. Roth, PhD; Erling Skancke, MS; Akhil Vohra, PhD; Irene Lo, PhD; Marc L. Melcher, MD, PhD, J Grad Med Educ (2021) 13 (6): 764–767.  https://doi.org/10.4300/JGME-D-20-01422.1

"Residency and fellowship candidates are applying to more programs to enhance their chances of securing interviews and matching favorably. The COVID-19 pandemic has shifted interviews to video formats, which lowers interview-associated costs for applicants but may further increase application numbers.1  While a candidate's application to a training program communicates some interest in the program, the relative amount of interest is obscured when candidates apply to large numbers of programs. We suspect that, as a result, programs host large numbers of low-yield interviews.

"The number of interviews is steadily increasing, and there is widespread agreement on the need to ease congestion in the pre-Match evaluation process.2  Proposals to reduce this burden include signaling (organized, centrally-controlled protocol for limited communication of interest),3–5  capping the number of applications or the number of interviews,6,7  and an early acceptance matching program as in college admissions.8,9 

"We propose another solution, an “interview match” to address the expanding number of interviews.10  An interview match enables candidates and programs to express preferences privately by ranking their interview choices individually or in tiers. This may ease congestion in the “marketplace,” reduce costs for candidates, favor interviews that are more likely to lead to a match in the final Match, and avoid interviews unlikely to convert to a match. An interview match algorithm would match based on the same “deferred-acceptance” algorithm currently used by the National Resident Matching Program but adapted to a “many-to-many” setting where candidates and programs receive multiple interviews."

Dating and Search: who should propose? by Yash Kanoria and Daniela Saban

 Dating sites are often congested, with many of them having more men than women. Here's an analysis suggesting that there are efficiency gains to having the short side of the market (in this case the women) do most of the search, by requiring them to initiate contact...

Facilitating the Search for Partners on Matching Platforms by Yash Kanoria , Daniela Saban, Management Science, Published Online:19 May 2021 https://doi.org/10.1287/mnsc.2020.3794

Abstract: Two-sided matching platforms can control and optimize over many aspects of the search for partners. To understand how matching platforms should be designed, we introduce a dynamic two-sided search model with strategic agents who must bear a cost to discover their value for each potential partner and can do so nonsimultaneously. We characterize evolutionarily stable stationary equilibria and find that, in many settings, the platform can mitigate wasted search effort by imposing suitable restrictions on agents. In unbalanced markets, the platform should force the short side of the market to initiate contact with potential partners, by disallowing the long side from doing so. This allows the agents on the long side to exercise more choice in equilibrium. When agents are vertically differentiated, the platform can significantly improve welfare even in the limit of vanishing screening costs by forcing the shorter side of the market to propose and by hiding information about the quality of potential partners. Furthermore, a Pareto improvement in welfare is possible in this limit.

*******

Earlier:

Thursday, February 13, 2020

Online dating while female--the case of Bumble

NRMP Statement On Interviewing

 The National Resident Matching Program (NRMP) has a statement on interviewing, which precedes the NRMP match for new American doctors, and that reflects concerns that the interviewing process has become congested.

NRMP Statement On Interviewing

"The National Resident Matching Program® (NRMP®) has heard the concerns of learners and programs in the medical education community about the interview process and wants to encourage equitable practices among applicants and programs. As such we have developed the following recommendations. Although especially true during the enduring times of the pandemic, the recommendations align with the NRMP’s long-standing commitment to maintaining a fair, efficient, reliable, and transparent process for all. Recommendations also foster well-being among all parties.

"NRMP Recommendations for Programs:

1. Programs should conduct all interviews virtually for the 2021-2022 cycle.

2. Programs should extend interview offers that equal, not exceed, the total number of available interview slots.

3. Applicants should be given a minimum of 48 hours to respond to an interview offer.

"NRMP Recommendations for Applicants:

1. Applicants should make timely decisions about interview offers and promptly notify programs in which they are no longer interested, freeing up interview slots.

2. Applicants should give ample, adequate (e.g., one week) notice to programs in the event they change their minds and decline accepted interviews."

Emergency decision making and medical ethics for breakfast

 Saturday morning breakfast cereal (SMBC) has hidden a message for us here:

Congestion in transit in supply chains: pipeline inventory

 The recovery from the pandemic is revealing as many supply issues as the pandemic itself did. Here's an article in Forbes about congestion in transportation

How Traffic Congestion In Chicago Is Backing Things Up In Los Angeles: Pipeline Inventory Is Now A Big Logistics Problem  by Willy Shih 

"As retailers try to bring a surge of imports into their distribution centers, they are exceeding the capacity of logistics providers to move them through choked hubs like the Union Pacific Global 4 intermodal terminal in Joliet, Illinois outside of Chicago. A shortage of truck chassis means its difficult to get containers out of the terminal to warehouses, that in turn leads to congestion that makes it is difficult to unload trains. According to a recent discussion hosted by the Journal of Commerce on top importers, that means the traffic has backed up to the marine terminals in Los Angeles and Long Beach, and to a lesser extent Seattle/Tacoma. That’s why now would be a good time to understand what we mean by pipeline inventory.

...

"All those containers stuck at UP Global 4 are pipeline inventory for somebody, and rail congestion out of West Coast ports means pipeline inventory is building up there (and remember it’s on trucks and trains as well). The Port of Los Angeles Signal report for last week projects import volumes up 54.9% this week and 71.6% next week, with big jumps in on-dock and off-dock rail containers. So that furniture or freezer you are waiting for might be sitting in a container stack in a yard somewhere.

...

"The key question is will those goods stuck in pipeline inventory make it to the consumer while the demand is still there? The recent precipitous collapse in lumber prices suggests that as Americans shift towards a more normal consumption pattern, we might end up with a lot more of some goods than retailers planned. Neglect of pipeline inventory, or increased ordering to make up for the pipeline lag, is one of the major causes of the bullwhip effect in supply chains. Sophisticated retailers like Walmart or Target are probably always on top of how much inventory they have in the pipeline, but the challenge is will the demand still be there when those goods finally arrive? For fashion retailers, this could be “Hello, TJX” as they end up looking for help to liquidate excess inventory."

NRMP Position Statement On The (In)Feasibility Of An Early Match

 There has been some suggestion that dividing the resident match into early and late matches might be a way to address the congestion in applications and interviews that has bedeviled the transition from medical school to residency in recent years.  The NRMP now has a statement pointing out that there are serious problems with that idea.

NRMP Position Statement On The Feasibility Of An Early Match

"For the past eighteen months the National Resident Matching Program® (NRMP®) has been working closely with other national medical education organizations to examine the current state of the transition to residency. Conversations have focused on mitigating burdens for both applicants and programs in the selection and recruitment process and addressing uncertainty in the future of the interview cycle.

...

"Among the proposed solutions to current challenges in the transition to residency are calls for an early match. Specifically, NRMP has been asked to implement the Early Result and Acceptance Program (ERAP) pilot program proposed for Obstetrics and Gynecology, created through American Medical Association’s Reimagining Residency Grant, “Transforming the UME to GME Transition: Right Resident, Right Program, Ready Day One”. The stated goals of the ERAP pilot are to allow applicants to engage in strategic decision-making, reduce burden on programs while hypothesizing that the change will result in holistic review, and reduce necessary applications and interviews. ERAP calls for an early match to begin in September 2022 for the 2023 Match cycle. ERAP permits applicants to apply to a maximum of three programs in the early match with programs including up to 50% of their positions if they choose to participate. This statement outlines NRMP’s concerns about the structure of the ERAP pilot program, the lack of evidence supporting the proposed changes to the Match, the implications of an early match for the matching process, and preliminary findings of modeling an early match being conducted by experts in market design and the matching algorithm.

"The NRMP has reviewed the ERAP pilot program with consideration for whether changes to the matching process have the potential to inadvertently disadvantage Match participants. It is through that lens NRMP remains concerned with the following aspects of the ERAP pilot:

"Although voluntary, applicants may feel pressured to participate in an early match where up to half the available positions in a specialty may fill before the Main Residency Match® opens.

"There exists no mechanism for demonstrating how an early match will make visible less competitive applicants and those underrepresented in medicine, which is hypothesized in the project document.

"The proposed limit of three applications per applicant could force applicants to make compromises not present in the Match today. ...While the ERAP investigation team hypothesized that the application limit will increase holistic review by programs, there are no mandates to ensure that programs conduct holistic review nor are there restrictions on the number of applications programs may accept, interviews they may offer, or applicants they may rank. With no objective evidence to support the hypothesis, we cannot conclude that the proposed application limit would increase holistic review of applications.

"There exists no mechanism for safeguarding an applicant’s failure to match in the early match from programs as they enter the Main Residency Match, which could result in the applicant being viewed as less competitive.

"In addition to concerns about disadvantaging applicants, NRMP is mindful of possible behavior changes resulting from changes to the Match process that could affect Match outcomes for all Match participants.

• "The structure of an early match does not allow for mixed-specialty couples ranking or multispecialty individual ranking, which may cause applicants to reconsider their specialty choices, fundamentally changing their career path.
• "Programs may have insufficient information (e.g., clinical evaluations, MSPE, LORs) to evaluate applicants fully and fairly in the early match.
• Programs may see a surge in non-traditional applicants as the early match provides three opportunities to enter training through either the early match, the Main Residency Match, or SOAP®. This may result in an increased number of applications or applicants who may otherwise not select the specialty.
• Not matching in the early match is likely to increase the number of applications per individual in the Main Residency Match, as applicants enter a matching cycle with only half of the positions remaining available. This may increase stress, cost, and could adversely affect the wellness of applicants.

...

"it is important to first outline the core concepts of the match as a stable “market”. The Match was established in 1952, to solve a “congestion” problem in medical residencies involving applications, offers, and acceptances. In a May 2021 pre-submission working paper, Itai Ashlagi, Ph.D. and Alvin Roth, Ph.D. describe the consequences of congestion as “unraveling” where programs initially responded to congestion by making “exploding offers” that prevented applicants from considering many programs because they were pressed to accept an early offer, before knowing whether an offer from a more preferred program might be forthcoming if they waited. The authors note that NRMP’s matching process, in its current form, has four distinct properties that are relevant to managing the problems of congestion and unraveling and maintaining a stable matching market. Specifically, the NRMP matching process

"1. Is Uncongested: participants make all decisions (on Rank Order Lists) in advance, so there is no delay in processing offers, rejections, and acceptances, which is done by the computerized Roth-Peranson algorithm.

"2. Defers acceptances: preferences of applicants and programs are not finalized until all preferences have been considered, thereby producing stable matching: i.e., matching in which there are no “blocking pairs” of applicants and programs not matched to one another but who both would prefer to be.

"3. Promotes true preferences: it is safe for participants to state their true preferences when they submit their Rank Order Lists (ROLs).

"4. Establishes a “thick” market: most residency programs in most specialties participate in the NRMP Match, which also allows for multi-specialty applications and couple matching (including for mixed-specialty couples).

"The authors opine that an early match such as the proposed ERAP pilot followed by the Main Residency Match would not share three of the four important properties of the Match:

"1. An early match would dilute the thick market: not all positions would be available at the same time (and further, it would not allow applicants to express multi-specialty preferences, nor would it accommodate mixed-specialty couples).

"2. early match would introduce complicated strategic decisions into the formulation of ROLs: it would no longer be safe for participants to submit ROLs straightforwardly corresponding to their preferences.

"3. An early match would not produce a stable matching: there would be mutually disappointed blocking pairs of mismatched applicants and programs. This would also make it less safe to report ROLs that straightforwardly corresponded to preferences."

Congestion in applications and interviews, by Arnosti, Johari and Kanoria

 Here's a paper modeling the issue that some labor markets may face congestion related to large numbers of applications followed by costly interviews.

Nick Arnosti, Ramesh Johari, Yash Kanoria (2021) Managing Congestion in Matching Markets. Manufacturing & Service Operations Management 23(3):620-636. https://doi.org/10.1287/msom.2020.0927

Abstract. "Problem definition: Participants in matching markets face search and screening costs when seeking a match. We study how platform design can reduce the effort required to find a suitable partner. Practical/academic relevance: The success of matching platforms requires designs that minimize search effort and facilitate efficient market clearing.

"Methodology: We study a game-theoretic model in which “applicants” and “employers” pay costs to search and screen. An important feature of our model is that both sides may waste effort: Some applications are never screened, and employers screen applicants who may have already matched. We prove existence and uniqueness of equilibrium and characterize welfare for participants on both sides of the market. Results: We identify that the market operates in one of two regimes: It is either screening-limited or application-limited. In screening-limited markets, employer welfare is low, and some employers choose not to participate. This occurs when application costs are low and there are enough employers that most applicants match, implying that many screened applicants are unavailable. In application-limited markets, applicants face a “tragedy of the commons” and send many applications that are never read. The resulting inefficiency is worst when there is a shortage of employers. We show that simple interventions—such as limiting the number of applications that an individual can send, making it more costly to apply, or setting an appropriate market-wide wage—can significantly improve the welfare of agents on one or both sides of the market. 

"Managerial implications: Our results suggest that platforms cannot focus exclusively on attracting participants and making it easy to contact potential match partners. A good user experience requires that participants not waste effort considering possibilities that are unlikely to be available. The operational interventions we study alleviate congestion by ensuring that potential match partners are likely to be available.

And from the Conclusion:

"We also compare the effects of an application limit to those of other available levers: either raising application costs or lowering the wage paid to applicants. Although these interventions can lead to thesame aggregate welfare as an application limit, they differ in how they distribute this welfare. Charging fees and lowering wages both increase aggregate welfare at the expense of applicants. Although these interventions may be appropriate for a platform looking to monetize its services or attract more employers, an application limit can yield Pareto improvements in welfare and may be more suitable if the platform is primarily concerned with applicant welfare. These considerations might explain why the tutoring platform TutorZ charges tutors for each potential client that they contact, whereas the dating platforms Coffee Meets Bagel and Tinder limit the number of likes/right swipes permitted in a certain period."

Congestion in interviews for pediatric surgery fellowships

 In recent years, pediatric surgery has been a very popular subspecialty among Stanford surgical residents (upon completion of their 5 year general surgery residency).  A lot of time and treasure is spent interviewing for these relatively few fellowship positions: except in 2020 when interviews were remote, fellowship applicants pay for their own travel, etc.  And Stanford hospitals pull back on elective surgeries while the surgical residents are on the road interviewing.  Is so much interviewing inefficient?  Many think so, and here are some data.

Analysis of the pediatric surgery fellowship application process using the Thalamus™ database, by  Saunders Lin, Jason Reminick, Ephy Love, Benedict Nwomeh, Sanjay Krishnaswami, Journal of Pediatric Surgery, Volume 56, Issue 6, June 2021, Pages 1095-1100

"Background: The pediatric surgery fellowship interview process is costly and time intensive. We hypothesized that the increasing number of interviews completed by applicants and programs have become inefficient over time.

...

"Results: Our dataset included 34, 41, and 45 programs, which represented 81%, 91%, and 97% of all programs in 2018, 2019, and 2020, respectively. The median number of interviews completed per program remained constant, while the median number of interviews per applicant increased from 9.0 in 2018 to 13.0 in 2020. For 75% of programs, a program required only 4 or less candidates to fill their position. On average, 96% of program interviews do not result in a matched candidate.

"Conclusions: Programs offer interviews out of proportion to the number of positions available, and most applicants attend all interviews offered. We recommend an initial program goal of 20 interviews, which may be achieved by increased use of virtual interviews and the creation of program-level data on ideal applicant profiles.

...

"1. Introduction: With the advent of computer scheduling software and electronic interview platforms, data collection regarding the pediatric surgery fellowship interview process on a national level is now possible. One such platform is Thalamus, a scheduling software currently used for pediatric surgery fellowship interviews [1].

"The pediatric surgery match remains one of the most competitive fellowship application processes, with a total of 43 available positions for 78 applicants in the 2020 match cycle [2]. Published data show that extensive time and monetary resources are used every applicant cycle, with the average candidate spending around 14% of pretax salary and using up to three full weeks of residency days to complete interviews [3]. Despite these costs, however, programs continue to place considerable value on in-person interviews.

...

"2.1. Data source and methods: Thalamus is a comprehensive online and mobile Graduate Medical Education (GME) scheduling and communication software currently used in the pediatric surgery interview process. For applicants, features include a real-time scheduling system with online and mobile compatibility that allows applicants to self-schedule and instantly confirm their interview dates. From a program perspective, Thalamus is able to handle all interview confirmations, cancellations and rescheduling, and allows for comprehensive collection of applicant and program data both on the aggregate and individual levels.

"Thalamus was founded in 2013 and has been used in pediatric surgery since December 2016. The software is also currently used by more than 2200 residency and fellowship programs at more than 200 hospital systems across more than 100 specialties. It segments each institution by institutional ID and each program within each institution by program + ACGME ID (or a similar number for non-ACGME accredited programs). This is a cloud hosted database on the Microsoft Azure/SQL Server. Thalamus maintains several IRB approved/exempt research relationships with various specialties and other leadership organizations in Graduate Medical Education. This data is not shared between programs nor any other organization outside of Thalamus.

"We performed a retrospective investigation using Thalamus to identify population-level parameters regarding the pediatric surgery match between 2018 and 2020. This study was deemed exempt from approval by the Oregon Health and Sciences University Institutional Review Board as it did not contain patient data and applicant data was de-identified.

"3.2. Individual program and applicant data: With regards to individual program and applicant match data, the mean number of interviews offered and completed per program were similar in all three years (Table 2). The highest number of interviews a program completed was 44 in 2020. The number of interviews offered and completed per program have remained constant during the time-period. In contrast, both the mean and median number of interviews received and completed by applicants have increased. The median number of interviews completed per applicant increased 33.3% between 2018 and 2019 and an additional 12.5% between 2019 and 2020. Furthermore, the number of applicants who complete three or less interviews have been decreasing in the past three years: 25% in 2018, 20.6% in 2019, and 11.4% in 2020. Conversely, the number of applicants who completed more than 20 interviews has also been increasing in the past three years.

Covid vaccine congestion in France looks familiar

France is some weeks behind the U.S. in delivering vaccines, but the script will look familiar to Americans.

The  Financial Times has the story:

France finally gets its Covid vaccination act together. The country’s inoculation drive has picked up speed after a slow start. by David Keohane 

"All it took to get my first dose of the Covid-19 vaccine in France was a five-hour round trip and two days and eight hours of incessant refreshing at my computer. 

...

""Until May 12, younger people in France weren’t allowed to book a vaccination unless they suffered from an underlying health condition which pushed them up the queue. 

"Since then anyone can book as long as the dose is set to go begging in the following 24 hours."