In welfare economics, the theory of the second best concerns the situation when one or more optimality conditions cannot be satisfied.[1] The economists Richard Lipsey and Kelvin Lancaster showed in 1956 that if one optimality condition in an economic model cannot be satisfied, it is possible that the next-best solution involves changing other variables away from the values that would otherwise be optimal.[2] Politically, the theory implies that if it is infeasible to remove a particular market distortion, introducing one or more additional market distortions in an interdependent market may partially counteract the first, and lead to a more efficient outcome.[3]
Lipsey
was invoked but never defined (see the help page).