“Externality Mixâ€: A Case of Terminological Variability

Buchanan has made a significant contribution to joint supply theory by emphasizing the relevance of technological variability to welfare optimality conditions. This paper shows that it is the joint supply relationship in his analysis—not the externality relationship—that should be labeled multidimensional. Buchanan's graphical model is replaced with a modified version of Lancaster's consumption model so that Buchanan's “externality mix†can be readily identified as a misnomer for “joint-product mix.†This demonstrates what Buchanan himself asserts: an externality implies, but is not implied by. the presence of joint supply.