It is precisely because data comes out murkily, with a lag - and the effects of changes have a lag as well- that managing the Federal Reserve can't by reduced to a simple process. It is an art done by humans- one where 'general trust in the institution' is the single most important variable of the last 40 years.
Many economists point out that the Fed's policies serve the 1% above all.
Heck you can get a Nobel Prize based on your Fed chairmanship, then tank the economy.
One pundit observes that the Fed is an example of "burn the village to save the village" as (rarely) an underemployed firefighter-turned-arsonist will do. Extreme perspective for sure.
In the era of Big Data, can't real-time data and policy co-exist?