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Congested waiting lists and organ allocation

Itai Ashlagi Ravi Jagadeesan Pengyu Qian

Stanford Stanford Boston University

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The waitlist for kidneys in the US (2015-2023)

~90k patients on the waiting list today

Waiting times typically between 3-5 years

Year (and non-utilization rate)

Count

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Lower quality kidneys require more offers till acceptance

Kidney Donor Percentile Index (KDPI) bin

Median # of offers until acceptance

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Organs degrade over time

Hours from organ recovery to response time

% of refusals due to cold time

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This paper

with perishable organs, waiting lists can become congested, leading to wastage

patients near the top of the list may decline to accept low-quality organs
patients further down the list might very well accept one

friction: limited number of patients can consider an organ before it expires

i.e., accrue excess cold ischemia time

so lower quality organs may expire before being offered to patients who would accept them, despite there potentially being many such patients

this paper: formalize this force and investigate implications for welfare and policy

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Model

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Structure of the queue

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Congestion

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A congested steady state

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A congested steady state

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Impact of congestion on steady state

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Constrained inefficiency under congestion

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Delegation to doctors and congestion

in practice, doctors make acceptance decisions on behalf of patients

doctors are penalized only for post-transplant adverse outcomes, so may be disincentivized from accepting lower-quality kidneys

Mehrotra et al. (2022); Sepulveda et al. (2023); Chan and Roth (2024)

we show: when healthy patients are more willing to wait for safe organs,�delegation worsens congestion and raises both steady-state waiting times

so delegation can harm even patients whose doctors are not too risk-averse

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Conclusion

organ expiry can lead to congestion on deceased donor waiting lists
in paper: possibility of self-fulfilling congestion that harms everyone
delegation to risk-averse doctors can worsen congestion and harm welfare

potential improvements to market design:

expedite offers of low-quality organs, or create separate waiting lists by organ types (Castro et al., 2020) or control deferrals (Schummer, 2021)
relax hospitals’ disincentives for accepting risky organs

methodological: bringing monotone comparative statics to queuing theory