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Commons are resources used by many individuals in a commonly agreed way. In general the concept covers different issues such as natural resources (e.g. the air) or intellectual resources (e.g. software programs). Here we are concerned with natural resources.

Scholars are still in the process of developing a shared language for referring to ‘the commons’ (Ostrom 2008). There is frequently confusion between concepts such as ‘common-pool resources’, ‘common-property resources’, ‘open access resources’, ‘public goods’ and ‘commons’. ‘Public goods’ for example refers to goods for which it is difficult to limit access. 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).

Commons or ‘common-pool resources’ instead are characterised by divisibility, which makes them different from public goods. They often appear as ‘open-access resources’ or as ‘common-property resources’. 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. Furthermore, one person’s use of such resources can subtract benefits that others might enjoy’. For instance, while one person using open air to breathe, does not hamper anybody’s else’s use, using the atmosphere as a sink for large amounts of sulphur dioxide or carbon dioxide, does prevent other people from making similar use of it.

Common and Stagl (2005) consider that common-property resources mostly include cases where rights are held by communities of individuals, including the government and non-government organisations. Their use can be regulated in a variety of ways by a variety of institutions. However, sometimes private property rights exist for common-pool resources, but either it is so costly to enforce them that they are not exercised or the owner does not enforce them.

In synthesis, the shared elements in the definition of commons 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. The main challenge how to best make use of commons is the governing of the commons.


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.


For further reading

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

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


Useful website


This glossary entry is based on a contribution by Rui Santos.

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

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