Economies evolve and are subject to sudden shifts precipitated by legislative changes, economic policy, major discoveries, and political turmoil. Macroeconometric models are a very imperfect tool for forecasting this highly complicated and changing process. Ignoring these factors leads to a wide...

Historically, the theory of forecasting that underpinned actual practice in economics has been based on two key assumptions -- that the model was a good representation of the economy and that the structure of the economy would remain relatively unchanged. In reality, forecast models are...