Fundamental structural features of the economy, known by more familiar names such as the "natural rate of unemployment", "potential output growth", "neutral real interest rate" – what FED Chairman Mr. Jerome Powell called the "stars"1 – change location significantly over time, making "navigating by the stars" rather challenging.
Furthermore, even seemingly simple issues, such as establishing causal links rather than merely finding correlations among various economic variables, require lengthy discussion and often lead to clashes of opinions. Second, the effectiveness of central bank policies is based on adequate communication. And communication boils down to presenting stories that shape the expectations of market participants regarding future monetary policy.