Interpreting Permanent Shocks to Output When Aggregate Demand May Not Be Neutral in the Long Run

This paper studies a popular statistical model of permanent and transitory shocks to output using a set of arguably more plausible structural assumptions. One way to structurally interpret the model is by assuming aggregate demand has no long-run output effect. However, many economic theories are inconsistent with that assumption. Instead, we reinterpret the statistical model assuming a positive shock to aggregate supply lowers the price level and in the long run raises output while a positive shock to aggregate demand raises the price level. Under these assumptions, a puzzling finding from the empirical literature implies that a positive aggregate demand shock had a long-run positive effect on output in pre-World War I economies.