Common resource

A common resource is a resource that is available to everyone and provides benefit to the users but decreases in value as more and more people use it.[1] Two defining characteristics of a common resource are rivalry and nonexcludability:

  • Nonexcludabiity- Regarding common resources, nonexcludability refers to the inability to exclude others from using the resource. It is almost impossible to stop individuals from polluting the air or catching fish, without incurring a cost.[2]
  • Rivalry- A common resource is a rival good because as one person uses the resource, it decreases the value of it or the quantity available for others. Compared to a non-rival good which does not decrease the value or quantity.[3]

Even though a forest is renewable and will grow back in the long-run, in the short-run, a forest does not replenish itself, assume that within a year there are 10 people who use a public forest , if there are 1000 trees in the forest every time one person cuts a tree down to use there is one less tree available for the others to use. The forest is a common resource for the 10 people but as the amount of trees decreases, the rivalry between the 10 people increases as there are fewer trees fro each person to use.

Common resources can be easily confused with public goods which are available to everyone to use but differ because a public good is not a limited quantity. In the example above, there are only so many trees in the forest that people can use but the air that people breathe is unlimited. Air is considered a public good.

The overuse on common resources without though to moderation or conservation is what creates a tragedy of the commons.[4]

See Also

Read about these other types of goods to see why a common resource differs from other goods:

Excludable Non-Excludable
Rival Private good Common resource
Non-Rival Club good Public good


  1. J.Black, N. Hashimzade, and G. Myles. (2009) "Common Access Resource." [Online], Available:, 2009 [Aug 22, 2016]
  2. A. Goolsbee, S. Levitt and C. Syverson. Microeconomics. New York: Worth Publishers, 2013, pp. 666.
  3. M. Parkin and R. Bade. Economics: Canada in the Global Environment. Toronto: Pearson, 2013, pp. 392.
  4. R.B. McKenzie and D.R. Lee. Microeconomics for MBAs: An Economic Way of Thinking for Managers. New York: Cambridge University Press, 2010, pp. 26.