from the Richmond Fed
Although the Fed sets monetary policy by committee, the views of the chair have often carried outsized weight in decision-making. Throughout the Fed’s history, central bank leaders have provided intellectual guidance during crises, defended policy independence, and served as points of communication for the public.
[click on image below to read the study]
Source: http://www.richmondfed.org/publications/research/econ_focus/2014/q1/pdf/federal_reserve.pdf