Common Property and Open Access Regimes
September 26, 2025
Rival? Does one user’s harvest reduce what’s left for others?
Excludable? Can users who haven’t paid be kept out?
Note
| Attribute | Private | State | Common | Open Access |
|---|---|---|---|---|
| Excludability | High | High (by law) | Group-limited | None |
| Who sets rules? | Owner(s) | Government | Co-owners | No one |
| Who captures rents? | Owner(s) | Public (in principle) | Co-owners | No one (dissipated) |
| Typical risks | Externalities; market power | Principal–agent problem; info gaps | Cohesion/monitoring failures | Overuse; collapse risk |
Note
Key distinction: Open access ⟂ Common property.
Open access = common property without effective rules or governance.
All open-access resources are common-pool resources (CPR), but not all common-pool resources are open access.
No exclusion ⇒ no one can secure surplus.
Each user ignores the stock externality imposed on others (and on the future).
With free entry, effort keeps expanding until per-user profit \(=0\).
Why does effort go too far?
Result: \(\;\;E_{OA} > E^{*}\) and all rents are dissipated.