Models · Model 002 · After Elinor Ostrom
Tending the Commons
Thirty fishers share one lake. Eight principles decide whether it lasts.
Elinor Ostrom studied communities that governed shared fisheries, forests, and water for generations, and in 1990 she named eight design principles their rules had in common. Here they are as switches on a lake fishery. Turn one off and watch what happens to the fish, the fishers, and the rules.
01 · The model
One lake, three bays
Gold water is full of fish and pale water is fished out. Each dot is a boat. Press Run, then switch principles off and on while the seasons pass.
All eight principles are on. Press Run.
The eight principles
The lake and the rules
FishKeeping the rulesRespect for the rules
Members' income
Each seasonEight-season averageA normal season
02 · The test
Take one away
Each row runs the lake 40 times for 150 seasons, each run with its own weather. With all eight principles the lake comes through. Take any one away and it does worse, each in its own way.
- All eight 100% of lakes still alive 82% of a normal income
- Without clear boundaries 100% of lakes still alive 22% of a normal income
- Without rules that fit 25% of lakes still alive 35% of a normal income
- Without a say in the rules 80% of lakes still alive 54% of a normal income
- Without fishers monitoring 15% of lakes still alive 37% of a normal income
- Without graduated sanctions 40% of lakes still alive 42% of a normal income
- Without cheap conflict resolution 95% of lakes still alive 68% of a normal income
- Without the right to organize 85% of lakes still alive 60% of a normal income
- Without a lake-wide council 90% of lakes still alive 60% of a normal income
- None of them 0% of lakes still alive 8% of a normal income
Income is what an average member earns in a season, after costs and fines, compared with a normal season's catch when everyone keeps the limit.
Without monitoring, or without rules that fit the lake, the lake usually collapses, and harsh fines in place of graduated ones lose it more often than not. Without clear boundaries it nearly always survives, but a handful of outsiders land more than a third of the catch, and members earn less than in any other row but the last. The other four principles fail more quietly: the lake usually lives on, with fewer fish and poorer fishers. With every principle switched off, the lake collapses in every run.
That matches the larger lesson of Ostrom's work and of the studies that followed it. The principles work as a set, and a commons missing one of them is fragile.
03 · How it works
Fish, fishers, and rules
The fish. The lake is a grid of patches. Each season the fish in a patch grow back, fastest when the patch is about two-thirds full, and drift between neighboring patches. A patch fished below 8 percent of what it can hold can no longer recover on its own, and when the whole lake falls that low it is gone. Some years are better than others, and good and bad years come in runs.
The fishers. Ten fishers live on each bay. Each season a fisher makes up to nine trips, each to the fullest of five spots they check, and stops when a trip wouldn't pay its way. Fishers who keep the rules stop at the season's limit. Rule-breakers keep going. Now and then a fisher who keeps the rules has a hard season and goes over.
The choices. Each season some fishers rethink what they do. They compare notes with another fisher, usually from their own bay, and tend to copy whoever is doing better. Money is not all that counts: keeping the rules is worth more when the rules are respected and most of the bay keeps them too. Respect rises when fishers write their own rules, when the rules fit the lake, and when disputes are settled fairly. It falls when outsiders override the rules and when fines feel unfair.
- Lake
- 821 patches of water in three bays
- Fishers
- 30 members, ten to a bay, plus outsiders when the lake is open
- Season
- Up to nine trips per boat, then the fish grow and drift
- Limit
- About 9 percent of the fish in an average year, when the rules fit the lake
- Collapse
- Fish below 8 percent of what the lake can hold
- Code
- About 300 lines of JavaScript, running in this page
| Principle | Switched on | Switched off |
|---|---|---|
| 1Clear boundariesOstrom: Clearly defined boundaries | Only the thirty members of the three bays fish the lake. | Anyone may fish. Outsiders arrive when the fishing is good, keep no limit, and leave when it turns poor. |
| 2Rules that fit the lakeOstrom: Congruence between rules and local conditions | Each season's limit is a share of the fish in the lake, smaller in bad years, and fishing stops when stocks run low. | A fixed limit, set for an average year, stays put in good years and bad, and when stocks run low. |
| 3Fishers make the rulesOstrom: Collective-choice arrangements | Members revise the limit every season, and they respect rules they wrote. | A distant agency revises the limit every eight seasons, and members respect its rules less. |
| 4Fishers monitorOstrom: Monitoring | Fishers take turns checking each other's catches, and report what they find when they respect the rules. | An inspector from outside checks one catch in ten. |
| 5Graduated sanctions | A first offense costs the excess catch and a small fine. Each repeat costs more. | Every offense costs the excess catch and a heavy fine. Neighbors hesitate to report each other, and a fisher hit hard for one bad season may stop cooperating. |
| 6Cheap conflict resolutionOstrom: Conflict-resolution mechanisms | A fisher wrongly flagged clears their name at a meeting, and trust mends quickly. | A wrong accusation stands, fine and all. Resentment builds, and trust mends slowly. |
| 7Right to organizeOstrom: Minimal recognition of rights to organize | Outside authorities leave the local rules alone. | Now and then an outside authority sets the local rules aside for six seasons: the lake opens, a fixed limit applies, and an inspector does the checking. |
| 8Lake-wide councilOstrom: Nested enterprises | A council of all three bays counts each catch against the limit wherever it is landed. | Each bay polices only its own waters. Catch taken in another bay goes uncounted, so rule-breakers fish their neighbors' bays. |
04 · What to try
Five experiments
Each button sets the switches and starts a new lake. Every run has its own weather, so run each one a few times.
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Open the lake
Outsiders arrive while the fishing is good, and they keep no limit. The members keep theirs, and it shrinks as the stock falls. The lake survives, but a handful of outsiders land more than a third of the catch, and each one earns about three times what a member does.
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Stop watching
Breaking the limit now pays. Watch rust spread from boat to boat, often in one bay before the others, until the fish can't keep up.
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Set the limit once
A fixed limit works in average years. Wait for a run of bad ones: the limit doesn't shrink, the boats keep landing it, and the stock crosses a line it can't come back from.
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Punish harder
Every offense now draws a heavy fine, and yet rule-keeping erodes. Neighbors stop reporting each other, and fishers fined hard for one bad season stop cooperating.
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Let outsiders overrule
Every so often an outside authority sets the local rules aside for six seasons. Watch for the notice on the map, the outsiders who come with it, and how long the lake takes to recover.
Sources
Reading and code
- The principlesElinor Ostrom, Governing the Commons: The Evolution of Institutions for Collective Action, Cambridge University Press, 1990
- The evidenceMichael Cox, Gwen Arnold, and Sergio Villamayor Tomás, A Review of Design Principles for Community-based Natural Resource Management, Ecology and Society 15(4): 38, 2010. A review of 91 studies that tested the principles.
- In combinationJacopo A. Baggio and others, Explaining Success and Failure in the Commons: The Configural Nature of Ostrom's Institutional Design Principles, International Journal of the Commons 10(2): 417–439, 2016. Sixty-nine cases in which the principles worked in combination, with rules that fit local conditions mattering everywhere.
- The dilemmaGarrett Hardin, The Tragedy of the Commons, Science 162: 1243–1248, 1968
This is a teaching model, not a forecast. Its numbers, from how fast the fish grow to how much respect for the rules is worth, were chosen so that each principle has a visible job. They were not measured from a real lake, so the ranking in the test reflects those choices. The code is plain JavaScript and runs in this page.
Ostrom's research is one of three strands in Russell's book in progress, Commoning Consciousness.