Source: "Business Cycle Expansions and Contractions," National Bureau of Economic Research.It seems that the creation of the Fed might have had a stabilizing effect on business cycles. (How much of an effect is impossible to tell, given the many other variables at work.)
But...the graphs don't depict the relative severity of the various contractions. It is worth noting that the worst of them all -- the Great Depression -- occurred after the creation of the Fed and, in part, because of actions taken by the Fed. (A note to the history-challenged: The Great Depression began in September 1929 and ended only because of America's entry into World War II.)
In any event, the long-run cost of economic stability has been high. (See this and this, for example.)
