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 it works
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.
How to use it
- 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.
Worked example
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 it fails
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.
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
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.