For some time now it has become commonplace for people to describe business cycles by how they resemble one letter or another, although obviously this amounts to a lot of hand waving. But it does provide bright images. Thus Trump and crew seem to believe that the US will experience a V recovery, one that will boom up as rapidly as it fell down, so the sooner we can reopen America the sooner he can get that boomy upturn to guarantee his reelection. Somehow he fails to understand that if he gets it going too soon, the uptrun is more likely to get sideswiped by a serious Second Wave of the coronovirus that would turn the upturn back into a downturn, making it into a W, or if, as I suspect, given that the downturn we have just seen pushing the unemployment rate upo 10% in two months is truly unprecedented so that the upturn will not be all that fast, the outcome will not be a neat W, but a Wiggly W.
Use of letters is recent, but debates on the shapes of macro fluctuations is very old, dating back into the 19th century. Up until the 1930s, nearly all the discussion focused on “commercial crises” generating sharp downturns that then were asymmetrically followed by slower upturns. This was still the view in 1913 when Wesley Clair Mitchell of the NBER and Columbia published his Business Cycles, coining that term. I have been recently over on Econbrowser taken to describing such a pattern as a “Lazy J.” Think of a J but then tilt it to the right so its upslope gets flatter until it is flatter than the downturn. I think this is what we are going to see now in the US, although it could turn into a Wiggly W.
In the 1930s, driven by Mitchell associated at the NBER, it became common to use sine curves to describe business cycles, so symmetric, and if one cuts one off at the inflection points going down and up, something that looks like a U. Over on Econbrowser, Jeffrey Frankel recently posed that the current situation might end up looking like a U, although I doubt it.