Price rigidity and market-clearing: a conceptual clarification
区分了三种不同的“刚性”概念，指出只有前两种（外生终态刚性和均衡终态刚性）会导致市场配给，而过程刚性（缓慢调整）并不必然导致市场非出清，澄清了经济学中一个常见的因果混淆。
This article tests the view (derived from Hicks and Patinkin) that non-market clearance may be caused by slow adjustment ('process rigidity'). There are-models where market-rationing is present and derives from some form of rigidity, but this rigidity cannot be considered as process rigidity. It is similarly possible to accommodate the idea of process rigidity within the Marshallian research programme. What is missing is that market-rationing might be its corollary. The reason such a causal link is often believed to exist lies in a generic use of the concept of rigidity, used to designate alternative and incompatible phenomena: 'exogenous end-state rigidity' and 'equilibrium end-state rigidity', as well as process rigidity. It is true that these first two forms of rigidity create market rationing. The belief that slow adjustment also generates market rationing results from the unwarranted extension to process rigidity of conclusions which are only valid for the first two.