What happens when everyone helps—or waits?
Collective-action problems arise when individual incentives and group benefits differ. Ostrom's research shows why institutions and community rules matter to shared-resource governance.
Inside this model
Four people each start with 20. The total contribution is multiplied by m and split equally. Your payoff is 20−c+m(c+3o)/4; another person's is 20−o+m(c+3o)/4. Each extra unit you give returns m/4 privately and m to the group.
Out in the world
A practical use
Shared documentation, neighborhood maintenance and open-source work can benefit people who contribute different amounts.
A useful lens. Not a universal law.
- This one-shot model excludes punishment, reciprocity, communication and institutions. It is not a claim that real communities inevitably free-ride.
Associated thinkers
Further reading
Explore the original research or the teaching reference behind this experiment.
Elinor Ostrom — Beyond Markets and States ↗