Prior to the global financial crisis, Neoclassical Economists, i.e. the ones running the US Fed, would not even consider the level of private debt as a significant macroeconomic metric. That's changed slightly, but not really. They still delusionally believe that private debt doesn't matter UNLESS there's an exogenous shock which forces interest rates to the zero lower bound. They seem unwilling to accept the reality that rising private debt drives macroeconomic demand and that stabilizing or reducing private debt triggers an endogenous crisis a la Hyman Minsky's financial instability hypothesis.