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Lesson 5: The Tragedy of the Commons


download EWE Lesson 5 (.doc file)


  • Incentives
  • Property rights
  • Tragedy of the commons

Content Standards:

Standard 10:   Institutions evolve in market economies to help individuals and groups accomplish their goals. . . . [One] kind of institution, clearly defined and well-enforced property rights, is essential to a market economy.

Teacher Background:

In some neighborhoods, there is a rite of spring. The season brings on a flurry of environmental cleansing. Homeowners rush out to tend to their lawns, trees, bushes, and gardens. Winter debris gets picked up, bagged, and hauled away. Windows get repaired, fences get painted—and all this hap­pens without instruction from the government. Neighbors do what they can to make their environments beautiful, and the rest of us benefit from the beauty at no additional cost.

Of course, despite what would seem to be the obvious benefits, not all neighbors and not all neighborhoods take part.  One reason to opt out of this rite of spring has to do with property ownership. People who rent or live in govern­ment-provided housing are less likely to engage in the enthusiastic springtime cleanup than people who own the homes they live in. This generalization is not intended to disparage renters or to imply that “some people” just don’t care about their own living space. Instead, the point is that ownership creates strong incentives to maintain and improve the value of property. Indeed some of the same people who busily clean up the yards of the homes they own do nothing about the trash and litter that collects in nearby parks and lakes – that they don’t own.

The problem, referred to by economists as the tragedy of the commons, is best explained not in terms of people’s character or compassion, but in terms of the different incentives for users that accompany private and common ownership.  Simply put, people tend to take better care of things they own, and they tend to overuse, waste, or mistreat things they do not own. Unlike the owners of private property, users of common property derive benefits but do not pay the full costs of the benefits they enjoy. When not directly confronted with costs, individuals have no incentive to do anything about – or even be aware of – the costs their use imposes on others. As a result, the commonly-held resources are used too rapidly, their economic value is reduced, and much of the value is wasted.

Economic reasoning helps us understand that in terms of incentives, “everyone owns it” produces the same outcomes as “no one owns it.” When no one has the ability or incentive to control the use of the property—to decide how much each person gets, to decide whether to use it now or save it for later – poor use and overuse are predictable. This tragedy of the commons has long been recognized, and historical and real-world examples abound. The Boston Common—land set aside in colo­nial days as a place where residents could gather firewood and graze livestock—was quickly denuded, for example. The buffalo herds of the Great Plains were decimated by over-hunting and the species survived because private ranchers started their own herd – which they fenced and protected.

The lesson in the historical examples of private ownership is frequently ignored when it comes to issues of the environment. Young people (especially) often hold romantic views, assert­ing that land should be shared with all animals and humans, and that park and wilderness areas should be free for everyone to use. Ac­cordingly, they tend to favor common rather than private ownership of environmental amenities. Unfortunately, the effects of common ownership are usually the opposite of what romantics want; highly-cherished resources like parks, open space, wildlife, rivers and lakes suffer degradation through overuse.

 Like other resources, water is susceptible to the tragedy of the commons. Think, for example, of a public lake where owners (members of the “public”) derive benefits by using the lake for swimming, boating, and fishing, but don’t pay the full costs of keeping the water clean. The incentives encourage users to ignore the costs that their use imposes on others.  In contrast, when water rights are held privately, owners pay the costs of keeping the water clean enough for swimming or to support fish populations because they have an incentive to promote conservation and wise use. The antidote to the tragedy of the commons, then, is the development of private property rights rules so that owners who derive benefits from water and are discouraged from waste and degradation of their highly-valued resource.

 “IFQs, also known as “individual transferable quotas” are one solution governments around the world are adopting to address the tragedy of the commons in ocean fisheries by assigning property rights. A regulator or regulatory agency, in consultation with biologist, determines a sustainable fish population and sets a species-specific total allowable catch (TAC), typically by weight and for a given time period.  Portions of the TAC, called quota shares, are allocated to individual fishermen or fishing companies. Quotas can typically be bought, sold, or leased – a further reminder to the owner of the value of ensuring that the fish population is sustained. As of 2008, 148 major fisheries (generally, a single species in a single fishing ground) around the world had adopted some variant of this approach along with approximately 100 smaller fisheries in individual countries. Approximately 10% of the marine harvest was managed by ITQs as of 2008 http://en.wikipedia.org/wiki/Individual_fishing_quota (5/2012)  

  • For further information on IFQs, see The Property and Environment Research Center, www.perc.org, and enter “IFQ” in the search box.
  • See also:  Saving Ocean Fisheries  https://vimeo.com/23564293, a 5-minute video explaining how IFQs helped eliminate the tragedy of the commons in Alaskan fisheries; describing the(additional) benefits of safety and income for the fishermen; and detailing the consumer benefits that occurred.

The two short activities that accompany this lesson set up tragedies of the commons – one in water (lemonade) and the other in fish (M&Ms). The debriefing guides students through analysis of the different incentives embodied in common and private ownership and helps them understand how the rules of the game shape people’s behavior – and their use of valuable environmental amenities.

Activity:  M&Ms and Lemonade