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

This paper asks 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 imparts a dynamic, forward-looking aspect to saving behavior and leads to a model of aggregate demand that is tractable and usable with a wide variety of aggregate supply specifications. Theoretical applications concerning price level determinacy and inflation persistence are included.