The cobra effect
The cobra effect is when an attempted solution makes the problem worse, because the incentive it creates is gamed. People optimise the measure you reward rather than the outcome you wanted.
How does the cobra effect work?
Any reward attached to a proxy invites people to manufacture the proxy. If you pay for dead pests, severed feet, or closed tickets, you get more of those tokens — sometimes by creating the very problem you were paying to reduce.
People optimise the measure you reward, not the outcome you wanted.
How do you use the cobra effect?
- Designing bounties, KPIs, or quotas: ask “how would a clever, self-interested person hit this target without delivering the real outcome?”
- Policy and management: prefer rewarding the end result over an easily-gamed proxy for it.
- Pair with Goodhart’s law when any metric is about to become a target.
What does the cobra effect look like in practice?
Colonial-era Delhi reportedly offered a bounty for dead cobras to cut the snake population. Enterprising residents began breeding cobras to collect the reward; when officials scrapped the scheme, the now-worthless snakes were released — leaving more cobras than before.
Where does the cobra effect fail?
The famous cobra anecdote is illustrative and only loosely documented, so don’t treat it as proof. The robust point is the mechanism — incentives on a proxy get gamed — not the specific story.
- Not every incentive gets gamed, so assuming any scheme will backfire breeds a paralysis that prevents useful action.
- Telling a real cobra effect from ordinary noise requires measuring the actual outcome, not just watching the rewarded proxy.
- The model warns that incentives get gamed but offers no design for an incentive that resists gaming.
The counter-model: Skin in the game — Giving the incentive's designer and takers a stake in the true outcome, not the proxy, reduces the gaming that produces the cobra effect.
How do you apply the cobra effect, step by step?
- State the outcome you actually want and the proxy you plan to reward.
- Ask how someone could maximise the proxy without improving the outcome.
- Redesign the reward to track the outcome, or tie it to a stake in the real result.
- Measure the outcome directly after launch, not just the proxy.
- Adjust or withdraw the incentive if the gap between proxy and outcome opens.
Frequently asked
- What is the cobra effect?
- A perverse incentive in which a solution intended to fix a problem ends up worsening it, because people game the reward it creates.
- Where does the name come from?
- From an anecdote about a colonial bounty on cobras in India that led people to breed cobras for the reward, increasing the population.
- How is the cobra effect related to Goodhart’s law?
- Both describe gamed metrics: Goodhart’s law says a measure stops being a good measure once it’s a target; the cobra effect is the costly outcome when that gaming backfires.
Related
Keep reading
Skin in the game
Heads the banker wins, tails the taxpayer pays — and the reckless bets follow.
Go deeper
The book behind this idea: Freakonomics by Steven Levitt & Stephen Dubner. Hear the whole thing free — start an Audible trial and your first audiobook is on the house.
Read the full summary of Freakonomics →
More canonical picks:
- Thinking, Fast and Slow — Daniel Kahneman
- The Art of Thinking Clearly — Rolf Dobelli
- The Great Mental Models, Volume 1 — Shane Parrish
- Poor Charlie’s Almanack — Charlie Munger
- Super Thinking — Gabriel Weinberg & Lauren McCann
- Seeking Wisdom — Peter Bevelin
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Cite this page
ReadGlobe. (2026). The cobra effect. https://readglobe.com/model/cobra-effect/
"The cobra effect." ReadGlobe, 30 June 2026, readglobe.com/model/cobra-effect/.
Primary source: Wikipedia
Editorial synthesis © ReadGlobe 2026, drawing on the mental-models tradition (Charlie Munger, Farnam Street) and the primary sources for each model. · Last reviewed 2026-06-30.