Nudges vs. Prices (The Value of Behavioral Policies)
How much is a nudge worth? List, Rodemeier, Roy & Sun (NBER WP 35567 / BFI WP 2026-106, July 2026) argue the question only has meaning relative to an alternative instrument — and then answer it at meta-analytic scale: 1,200+ effect estimates from 600+ studies across five consumer markets (cigarettes, alcohol, influenza vaccination, household electricity, residential water).
The core move: equivalent price change (EPC)
Translate each nudge’s behavioral effect into the price change that would have produced the same effect, using the market’s estimated price elasticity. A behavioral intervention with a tiny treatment effect stops looking tiny when priced:
- Influenza vaccination: average nudge ≈ a 100% subsidy (pay people the full price of the shot)
- Electricity: average nudge (home energy reports) ≈ an 11% tax
- Alcohol: average nudge ≈ a 34% price increase
- Cigarettes: nudge EPC ~5% — within the range jurisdictions routinely enact
- Water: nudges cut consumption ~6.5% on average
The EPC also conveys political feasibility directly: a 5% cigarette-price equivalent is ordinary policy; the electricity equivalent would be a fight.
Cost-effective ≠ welfare-optimal
Nudges are more cost-effective than price instruments in all five markets — they are cheap to run, so behavior change per dollar is large. But extending the Marginal Value of Public Funds framework behaviorally, the authors show cost-effectiveness does not predict the welfare ranking: nudges have high welfare returns at the margin (MVPFs: electricity 2.0, water 2.3, alcohol 4.4), while price instruments often generate larger total surplus at scale. Cigarettes are the only market in the sample where nudges dominate on welfare. Results are robust to publication-bias correction.
The paper grows out of the authors’ earlier Judging Nudging (NBER WP 31152, 2023; 300+ hand-coded estimates, three markets) — the 2026 paper expands to five markets and rebuilds the theoretical frame.
Why it matters beyond policy
The frame is portable anywhere behavioral interventions compete with structural ones: evaluate the intervention against the alternative, not against zero. Enterprise security is the immediate instance — security-awareness-training is a nudge-family intervention whose measured effects are small, and the right comparison class is technical controls (passkeys, filtering), not the absence of training. The nudge/price asymmetry (cheap at the margin, outscaled at volume) maps neatly onto training (cheap to assign, weak) vs. engineering (expensive, decisive).
Connections
- security-awareness-training — the enterprise-security instance of behavioral-intervention evaluation; converging answer shape
- moral-economy-price-tag — prices as moral technologies; what it means when a 34% price move and a reminder email are “the same” intervention
- invisible-hand — price mechanism doing work a behaviorist must spend administrative effort to mimic
- competitive-rent-extraction — the dark mirror: firms running behavioral interventions on captive users, with no welfare framework in sight
- demand-governance-wedge — private adoption vs. governance preferences for emerging tech; another case where instrument choice is the policy