Editing Supply and demand (section)

==Criticism==
[[Piero Sraffa]]'s critique focused on the inconsistency (except in implausible circumstances) of partial equilibrium analysis and the rationale for the upward slope of the supply curve in a market for a produced consumption good.<ref>Avi J. Cohen, "'The Laws of Returns Under Competitive Conditions': Progress in Microeconomics Since Sraffa (1926)?", ''Eastern Economic Journal'', V. 9, N. 3 (Jul.-Sep.): 1983)</ref> The notability of Sraffa's critique is also demonstrated by [[Paul Samuelson]]'s comments and engagements with it over many years, for example:
:What a cleaned-up version of Sraffa (1926) establishes is how ''nearly empty'' are ''all'' of Marshall's partial equilibrium boxes. To a logical purist of Wittgenstein and Sraffa class, the ''Marshallian partial'' equilibrium box of ''constant'' cost is even more empty than the box of ''increasing'' cost.<ref>Paul A. Samuelson, "Reply" in ''Critical Essays on Piero Sraffa's Legacy in Economics'' (edited by H. D. Kurz) Cambridge University Press, 2000</ref>

Modern [[Post-Keynesians]] criticize the supply and demand model for failing to explain the prevalence of [[administered prices]], in which retail prices are set by firms, primarily based on a mark-up over normal average unit costs, and are not responsive to changes in demand up to capacity.<ref>Lee, F. S. (1999). Post Keynesian price theory. Cambridge University Press.</ref>