Human action cannot be analyzed in the same way that one would analyze objects. These quantitative methods do not improve our knowledge of the driving causes in economics.
The Fed overestimated the robustness of the economy, underestimated the level of addiction of the markets to cheap money, and it was way too quick to proclaim a “full recovery” from the crisis.
It's true that JFK would feel at home in the modern GOP. But that's because the GOP has stopped even pretending to want significant cuts to government spending.