25 The reason for the confidence interval is that the economy is frequently buffeted by shocks and thus rarely evolves as predicted.
See Janet L. Yellen (2016), “The Federal Reserve’s Monetary Policy Toolkit: Past, Present, and Future,” speech delivered at “Designing Resilient Monetary Policy Frameworks for the Future,” a symposium sponsored by the Federal Reserve Bank of Kansas City, held in Jackson Hole, Wyo., August 26, https://www.federalreserve.gov/newsevents/speech/yellen20160826a.htm.