This review article tries to answer four questions: (i) what are the stylized facts about uncertainty over time; (ii) why does uncertainty vary; (iii) do fluctuations in uncertainty matter; and (iv) did higher uncertainty worsen the Great Recession of 2007-2009? On the first question both macro...

Uncertainty varies strongly over time, rising by 50% to 100% in recessions and by up to 200% after major economic and political shocks. This paper shows that higher uncertainty reduces the responsiveness of R&D to changes in business conditions - a "caution-effect" - making it more persistent...

We propose uncertainty shocks as a new shock that drives business cycles. First, we demonstrate that microeconomic uncertainty is robustly countercyclical, rising sharply during recessions, particularly during the Great Recession of 2007-2009. Second, we quantify the impact of time-varying...

The U.S. economy hit bottom in June 2009. Thirty months later, output growth remains sluggish and unemployment still hovers above 8%. A critical question is why. One view attributes the weak recovery, at least in part, to high levels of uncertainty about economic policy. This view entails two...

The U.S. economy hit bottom in June 2009. Thirty months later, output growth remains sluggish and unemployment still hovers above 8%. A critical question is why. One view attributes the weak recovery, at least in part, to high levels of uncertainty about economic policy. This view entails two...

This review article tries to answer four questions: (i) what are the stylized facts about uncertainty over time; (ii) why does uncertainty vary; (iii) do fluctuations in uncertainty matter; and (iv) did higher uncertainty worsen the Great Recession of 2007-2009? On the first question both macro...

We propose uncertainty shocks as a new shock that drives business cycles. First, we demonstrate that microeconomic uncertainty is robustly countercyclical, rising sharply during recessions, particularly during the Great Recession of 2007-2009. Second, we quantify the impact of timevarying...