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Common-pool resources

According to Ostrom (2008), scholars are still in the process of developing a shared language for the broad set of things called ‘the commons’. There is frequently confusion about similarities and differences across concepts such as ‘common-pool resources’, ‘common-property resources’, ‘open access resources’ and ‘commons’ in general. Ostrom (2008) considers that ‘commons’ refers to systems, such as knowledge and the digital world, in which it is difficult to limit access, but one person’s use does not subtract a finite quantity from another’s use. This definition is close to the concept of ‘public goods’ in economics. Public goods are simultaneously characterised by non-exclusivity (implying that resources can be exploited by anyone since nobody has an exclusive right) and indivisibility (implying that the use of part of the resource by one individual or group does not subtract from the amount available to others).

‘Common-pool resources’ are characterised by divisibility, which makes a difference to public goods, and include open-access resources as well as common-property resources, in opposition to private property resources. The latter are held by individuals and firms creating the basis for the functioning of markets. Ostrom (2008) sees common-pool resources as ‘… sufficiently large that it is difficult, but not impossible, to define recognised users and exclude other users altogether. Further, each person’s use of such resources subtracts benefits that others might enjoy’. For instance, one person using open air to breath, does not hamper anybody’s else’s use, while using the atmosphere as a dumping ground for large amounts of sulphur dioxide or carbon dioxide, prevents other people from making (without damage to all) a similar use of it.

Common and Stagl (2005) consider that common-property resources include cases where rights are held by communities of individuals, including the government and non-government organisations, and their use can be regulated in a variety of ways by a variety of institutions. Sometimes, property rights exist for common-pool resources, but it is so costly to enforce them that they are not exercised. In this case, the common-pool resource has a size or characteristics that make it costly, although not impossible, to exclude potential beneficiaries from obtaining benefits from their use. However, besides the property rights enforcement constraints, it must be recognised that not everything is subject to property rights of some kind.

For this reason, we need to consider also open-access regimes where no one owns or exercises control over the resources. Open-access resources can be considered a type of common-pool resources where anyone can enter and/or harvest. Open-access resources can be exploited on a first-come, first-served basis because no individual or group has the capacity or the legal power to restrict access, promoting a ‘use it or lose it’ situation (Tietenberg and Lewis, 2009). Individuals making decisions on the basis of benefits and costs to themselves will ignore the common-property externalities they inflict on others. Each individual has no incentive to reduce the rate of use and conserve the resource. Economic theory considers this a ‘market failure’ and suggests several direct consequences, concluding that these resources are often overexploited. The open-access problem is known popularly but incorrectly as the ‘tragedy of the commons’. Open-access resources may be overexploited but common property resources need not suffer overuse and their allocation can be regulated in a way that avoids tragedy.

In synthesis, the shared elements in the definition of common-pool resources include (1) partial or total non-exclusivity, implying that resources can be exploited by any one individual or community since nobody individually has an exclusive right, and (2) divisibility, implying that the use of part of the resource by one individual or group subtracts from the amount available to others.

Fisheries and forests are examples of two common-pool resources that are currently of great concern. Some authors also rightly refer to groundwater basins, pastures and grazing systems, lakes, oceans and the earth’s atmosphere. In the two decades that followed the World Commission on Environment and Development (WCED) report Our Common Future (Brundtland, 1987), ‘… humans have failed to halt the tragedy of massive overfishing of the oceans, major deforestation, and excessive dumping of carbon dioxide in the atmosphere. However, in some specific niches, such as the Maine lobster fishery, the commons are in better condition today than they were a decade or two ago’ (Ostrom, 2008). Part of the reason for the mixed results is that most common-pool resources differ vastly from one another. Differences can be found, for example, in resource characteristics, socio-economic and cultural contexts and scales. However, granting due importance to management systems and property rights, it must be said that the main driving force of exhaustion of resources is population and economic growth.

The adequate management of a common-pool resource requires a deep understanding about the causes of  (potential/existing) conflict in resource use. Adams et al. (2003) emphasise that conflicts over the management of common-pool resources are not simply material, as they also depend on the perceptions of the protagonists. Since the problem definition is a critical phase in the policy-making process, it is essential to carefully and transparently consider the different stakeholders, their knowledge of the empirical context, their institutions, beliefs, myths and ideas. It is essential to promote an effective dialogue to find an adequate policy regime. Ostrom (2008) maintains that the advocacy of a single idealised solution for all common-pool resources has been a key part of the problem instead of the solution. She also considers that many of the most pressing problems future generations will face are on a global scale and that establishing effective governance arrangements on this scale has proved to be more difficult than on a local one.


Adams, W., Brockington, D., Dyson, J. and Vira, B. (2003) Managing Tragedies: Understanding Conflict over Common Pool Resources. Science, 302, (5652) 1915-1916.

Brundtland, G. H. (1987) Our Common Future: World Commission on Environment and Development, Oxford University Press Oxford.

Common, M., Stagl, S. (2005) Ecological Economics – an introduction. Cambridge University Press, Cambridge.

Ostrom, E. (2008) The Challenge of Common-Pool Resources. Environment, 50 (4) 9-20.  (available at:

Tietenberg, T. and Lewis, L. (2009) Environmental and Natural Resource Economics. 8th edition, Pearson International Edition, Addison Wesley, Boston.

This glossary entry is based on a contribution by Rui Santos

EJOLT glossary editors: Hali Healy, Sylvia Lorek and Beatriz Rodríguez-Labajos