Who Gets What — and Why: The New Economics of Matchmaking and Market Design

Market Design Foundations and Distinctions

• Al Roth, a 2012 Nobel laureate with a Ph.D. in operations research rather than economics, pioneered the field of market design to improve how societies and economies function.
• Commodity markets function where the identity of the counterparty is irrelevant (e.g., stock trading), relying solely on price to clear supply and demand.
• Matching markets (e.g., college admissions, labor markets) require bilateral selection where affordability alone does not guarantee a transaction; the agent must be chosen by the other party.
• Most real-world markets, including labor markets, exist on a spectrum between pure commodity and pure matching mechanisms, often requiring both price signals and matching protocols.

Market Frictions and Design Failures

• Thickness: Markets require sufficient participants to facilitate choices; failures occur when participants must commit to a single offer prematurely (e.g., law clerkships) without knowledge of future alternatives.
• Congestion: In thick matching markets, the time required to evaluate multiple simultaneous offers can lead to competitive disadvantages as competitors snap up candidates.
• Safety: Markets require mechanisms to ensure it is safe to reveal true preferences; without this, participants engage in strategic gaming (e.g., school applicants listing second-choice schools first to avoid rejection).
• Exploding offers: In markets where prestige dictates speed, participants make offers with vanishingly short acceptance windows (e.g., federal judicial clerkships), often forcing candidates to decide while unaware of better offers.
• The market for gastroenterologists historically failed due to an "arms race" where hospitals hired fellows two years in advance, fracturing a national market into inefficient local ones until redesign restored national mobility.

Specific Market Redesigns and Outcomes

• Kidney Exchange: Roth helped design a market allowing incompatible donor-patient pairs to swap kidneys, legally exempted from the National Organ Transplant Act's prohibition on valuable consideration.
  • Two-way exchanges require simultaneous surgery in four operating rooms to prevent reneging.
  • Chains initiated by "non-directed donors" can bypass simultaneity constraints, enabling cycles of 30 or more transplants.
  • Iran is the only country with a legal cash market for kidneys, reportedly resulting in a waiting list for donors rather than recipients.
• High-Frequency Trading (HFT): Roth supports Eric Budish's proposal to shift markets from continuous double auctions to "batch markets" clearing once per second.
  • This change would eliminate the incentive for millisecond-speed investing (microwave channels) and restore competition based on price rather than speed.
  • Implementation could involve a one-year grace period announcement to allow existing investors in speed infrastructure to adjust without sunk cost loss.
• BandwidthX: A proposed market design to trade unused Wi-Fi bandwidth from residential locations to cellular networks, smoothing peak loads and reducing the need for new infrastructure.
• Ride-Hailing: Uber succeeded by creating a thick market that bypassed inefficient local taxi monopolies, though challenges remain regarding driver classification, insurance liability, and regulatory compliance.

Societal Implications and Economic Policy

• Repugnance: Roth argues that public opposition to markets (e.g., buying kidneys) often stems from a lack of understanding of alternative structures; designing markets to mitigate harm (e.g., non-directed donor chains) can reduce "repugnance."
• Dialysis Funding: Medicare covers end-stage renal disease regardless of age, creating a costly entitlement; Roth suggests redirecting even a fraction of dialysis costs into incentives for non-directed kidney donation could save money and lives.
• Minimum Wage: Roth notes that labor markets are not purely commodity markets; paying above the minimum wage can be a market design strategy to reduce turnover and ensure match quality, though high minimums risk excluding entry-level workers.
• Criminal Justice: Mass incarceration related to drug crimes is linked to the creation of illegal black markets; Roth advocates for regulated legal markets (e.g., marijuana) as a potential design fix to reduce imprisonment.
• Higher Education: Rising tuition reflects a shift from taxpayer-funded subsidies to user fees; Roth suggests redesigning pricing through price discrimination (higher tuition with targeted financial aid) to better align costs with ability to pay while preserving access.
• Healthcare Redesign: Roth identifies self-insuring large corporations as the most promising venue for innovation, as they have incentives to fund preventative care (e.g., diabetes management) to reduce long-term treatment costs.
• Political Markets: Roth suggests the disconnect between campaigning (appealing to primary bases) and governing (seeking compromise) contributes to polarization, a problem akin to a flawed market design where incentives are misaligned.

Forward-Looking Statements and Open Questions

• Roth remains skeptical of Bitcoin as a global currency due to its fixed supply, which lacks the elasticity required for economic growth, though he acknowledges the utility of blockchain for transaction verification.
• The feasibility of paying individuals to sign "Do Not Resuscitate" contracts is debated, with Roth noting the complexity of public interest and potential ethical conflicts.
• Roth proposes that the optimal path for financial market reform may be a regulatory shift allowing batch markets rather than immediate mandates, requiring careful phase-in to address existing investments in speed.