From Local to Global Public Goods : How Should We Write the Utility Function

The literature on public goods provision has experienced a significant increase since Samuelson's (1954) paper. The common goal is to make the model more suitable to describe a more general class of non rival goods. However, there does not seem to be a consensus in the literature on the form of the function to be used to describe the externality created by the public good. In this note we try to show the hypotheses underlying the functions used. The different models proposed are optimal when used in the right framework and this should be kept in mind when choosing the function in relation to the type of public good one wants to study