The economic collapse in the wake of the global financial crises (GFC) and the weaker-than-expected recovery in many countries have led to questions about the impact of severe downturns on economic potential. Indeed, for several major economies, the level of output is nowhere near returning to pre-crisis trend (figure 1). Such developments have resulted in repeated downward revisions to estimates of potential output by private- and public-sector forecasters...
...Economic models usually assume that recession-induced gaps will close over time, typically via a period of above trend growth. In our results, growth is not faster after the recession than before, implying that the recession-induced gap is closed primarily by revising estimates of trend output growth lower. Interestingly, much of the downward revision to estimates of trend output happens well into the recovery. In particular, as economies recover and the lower level of actual output persists, potential output is gradually revised down toward actual GDP.
One reason output gaps are typically viewed as transitory is likely that techniques to calculate trend are often two sided, bending in response to the evolution of actual data...
...Although these calculations are simple, they raise deeper questions about the impact of recessions on trend output. The finding that recessions tend to depress the long-run level of output may imply that demand shocks have permanent effects. The sustained deviation of the level of output from pre-crisis trend points to flaws in the way the economics profession models the recovery of output to economic shocks and raises further doubts about the reliance on measures of output gaps to determine economic slack. For policymakers, the results also point to the cost of recessions, especially deep and long ones, and provide a rationale for strong and rapid policy responses to economic downturns.
www.federalreserve.gov/econresdata/notes/...lves-20141112.html
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