I Draw A Different Message From John Fernald's Calculations Than He Does

by: Brad DeLong

Over at the Equitablog: John Fernald: Productivity and Potential Output Before, During, and After the Great Recession: "U.S. labor and total-factor productivity growth...

...slowed prior to the Great Recession. The timing rules out explanations that focus on disruptions during or since the recession, and industry and state data rule out "bubble economy" stories related to housing or finance. The slowdown is located in industries that produce information technology (IT) or that use IT intensively, consistent with a return to normal productivity growth after nearly a decade of exceptional IT-fueled gains. A calibrated growth model suggests trend productivity growth has returned close to its 1973-1995 pace. Slower underlying productivity growth implies less economic slack than recently estimated by the Congressional Budget Office. As of 2013, about 3⁄4 of the shortfall of actual output from (overly optimistic) pre-recession trends reflects a reduction in the level of potential.

But when I look at this graph:

Www frbsf org economic research publications working papers wp2014 15 pdf

I see, from 2003:I to 2007:IV, a healthy growth rate of 3.2%/year according to Fernald's potential-output series. Then after 2007:IV the growth rate of Fernald's potential-output series slows to 1.45%/year. The slowdown from the late 1990s era of the internet boom to the pace of potential output growth prior to the Lesser Depression is small potatoes relative to the slowdown that has occurred since. Thus Fernald's claim that the "timing rules out explanations that focus on disruptions during or since the recession". As I see it, the timing is perfectly consistent with:

  • a small slowdown in potential output growth that starts in the mid-2000s as the tide of the infotech revolution starts to ebb, and
  • a much larger slowdown in potential output growth with the financial crisis, the Lesser Depression, and the jobless recovery that has followed since.

I say this with considerable hesitancy and some trepidation. After all, John Fernald knows and understands these data considerably better than I do. Perhaps it is simply that I spend too much time down in Silicon Valley and so cannot believe that the fervor of invention and innovation that I see there does not have large positive macroeconomic consequences.

Nevertheless, I have come to believe that macroeconomists think that their assumption, the trend is separate from and independent of the cycle are playing them false. This assumption was introduced for analytical convenience and because it seemed true enough for a first cut. I see no reason to imagine that it is still true.