An Optimizing IS-LM Specification for Monetary Policy and Business Cycle Analysis.

We ask whether relations of the IS-LM type can sensibly be used for the aggregate demand portion of a dynamic optimizing general equilibrium model intended for analysis of issues regarding monetary policy and cyclical fluctuations. The main result is that only one change--the addition of a term regarding expected future income--is needed to make the IS function match a fully optimizing model, whereas no changes are needed for the LM function. This modification leads to a dynamic, forward-looking model of aggregate demand that is tractable and usable with a wide variety of aggregate supply specifications. Theoretical applications concerning price level determinacy and gradual price adjustment are included.