"[3] However, the interpretation of chapter 3 (The Principle of Effective Demand) of The General Theory of Employment, Interest and Money remains confused.
Colin Rogers claimed that "What is missing is an appreciation of the principle of effective demand" as a theory of monetary economy.
[6] More recently, a symposium on the notion and interpretations of "Effective Demand: Securing the Foundations – A Symposium" was held as the 5th "Dijon" Post-Keynesian Conference at Roskilde University on 13th and 14 May 2011, in which Mark Hayes, Jochen Hartwig, and Olivier Allain participated, and was published in Review of Political Economy in 2013.
Olivier Allain pointed out that "[the General Theory] faces a closure difficulty between the macroeconomic outcomes and the microeconomic behaviour of firms.
"[7] Mark Hayes claimed that "We still need to agree by what mechanism individual entrepreneurs form a collective and mutually consistent state of expectation in the General Theory.