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...

We derive parametric tests for the role of the interest rate in specifications based on the firm's optimization problem. These Euler equation and decision rule tests mirror earlier evidence, finding little role for the interest rate. We present a simple and intuitively appealing explanation,...