Reflections on macroeconomics then and now

Many of the answers to key macroeconomic policy questions have changed markedly over the past halfcentury or so. While much of the analytical approach of the past remains valid, there have been important changes in the economic environment. Estimates of Phillips Curves are flatter than in the past; productivity growth is lower and concerns have arisen over secular stagnation; monetary policy has been affected by the zero lower bound and changes in the financial sector; activist fiscal policy seems to have fallen out of favor, and changes in the energy industry may have altered the relationship between the economy and the price of oil. The result is that some of the answers to policy issues are now different because the problems of today were not evident 50 years ago.