The large decline in the natural interest
rate early in the recession (shown in
Figure 1) may explain why the Federal
Reserve lowered the federal funds rate
so fast in 2008 even before the output
gap became negative. Interest rate rules
that ignore the variation of the natural
rate over time—like the one proposed in
Taylor (1993)—would not prescribe
dropping the federal funds rate so
quickly, which would lead to even
tighter monetary conditions and a more
negative output gap. Therefore, while
monetary policy was accommodative
relative to the Taylor rule, it was not accommodative enough to prevent the interest rate gap from
increasing and output from falling below potential, as shown in Figure 2.