The Samuelson condition, authored by Paul Samuelson, in the theory of public goods in economics, is a condition for the efficient provision of public goods. When satisfied, the Samuelson condition implies that further substituting public for private goods (or vice versa) would result in a decrease of social utility. For an economy with n consumers the conditions reads as follows: MRSi is individual i's marginal rate of substitution and MRT is the economy's marginal rate of transformation between the public good and an arbitrarily chosen private good.