Identification Using Stability Restrictions

Structural change, typically induced by policy regime shifts, is a common feature of dynamic economic models. We show that structural change can be used constructively to improve the identification of structural parameters that are stable over time. A leading example is models that are immune to the well-known Lucas (1976) critique. This insight is used to develop novel econometric methods that extend the widely used generalized method of moments (GMM). The proposed methods yield improved inference in a leading macroeconomic policy model.