Prisoners dilemma or tragedy of the commons: What is the difference between a public good and common resource good?
One thing that causes a lot of confusion, both in popular and academic debate, is the distinction between a pure public good and common resource good. Concepts like tragedy of the commons, prisoners dilemma, and free-riding get used far too liberally, and often incorrectly. So, here is one way of trying to untangle the differences: Suppose that I decide, out of the goodness of my heart, to provide a 'gift' to my local community. For example, I build a children's play-area, or renovate the village hall, or play very loud grunge music. This is a form of public good in the sense that it is non-excludable - anyone in the village is free to enjoy my gift. What distinguishes between a pure public good and common resource good is rivalry in consumption - does one person's enjoyment of my gift depend on the number of other people who make use of the good. Here are some examples: Loud music is a p...