What I meant was that those who claim that the Fed has reduced volatility since WWII appeal to studies that do not include the recent financial collapse. The study I linked to says the same thing: the performance of the Fed has been better since WWII than before WWII. Well, maybe, if you don’t include the Fed causing the recent boom-bust. The studies don’t include the recent boom-bust because they were published before the business cycle has run its course. Take a look at the study by Selgin, Lapstrates, and White at the link above.