This paper introduces a new approach to understanding investment. The distinctive feature of our approach is that shocks to the economic fundamentals have both persistent and transitory components, and that firms must disentangle the persistent from the transitory shocks. The model generates...

In this paper we derive tests for parameter constancy when the data generating process is non-stationary against the hypothesis that the parameters of the model change smoothly over time. To obtain the asymptotic distributions of the tests we generalize many theoretical results, as well as new...