Will It Issue a Correction??
[Note to Readers: The views expressed here are solely those of Ross Kaplan, and do not represent Edina Realty, Berkshire Hathaway, or any other entity referenced.]
If 10% of the economy shuts down for one quarter, that would be considered a 40% decline at an annual rate.”
–“Coronavirus Slump Is Worst Since Great Depression. Will It Be as Painful?”; The Wall Street Journal (5/10/2020).
If you can’t follow the math in the excerpt above — and I couldn’t — it’s because there appears to be a mistake: 
specifically, the “10%” and “40%” are reversed.
The mistake is easiest to grasp using concrete numbers.
So, assuming that annual U.S. GDP is $20 Trillion (it’s actually closer to $22 Trillion — or was), quarterly GDP looks like this:
Q1: $5 trillion
Q2: $5 trillion
Q3: $5 trillion
Q4: $5 trillion.
Annual GDP = $20T.
Now, assume that Q2 GDP — the current quarter that began April 1 — takes a 40% hit due to the Covid-19 pandemic, as many economists now expect:
Q1: $5 trillion
Q2: $3 trillion (40% decline)
Q3: $5 trillion
Q4: $5 trillion
Annual GDP = $18T; decline = $2T or 10% annual decline.
That would certainly appear to be what the WSJ author seemed to intend.
By contrast, here are the statistics using the author’s actual, reversed percentages:
Q1: $5 trillion
Q2: $4.5 trillion (10% decline)
Q3: $5 trillion
Q4: $5 trillion
Annual GDP = $19.5T; annual decline = 2.5% (not, “40% annual rate of decline”).
See what I mean??
See also, “WSJ Headline (Briefly): “Jeb Bush Says His Brother Gets to Give Eulogy Over President Trump”.
