One chapter of How Not To Be Wrong, called “More Pie Than Plate” (excerpted in Slate here) is about the perils you are subject to when you talk about percentages of numbers (like “net new jobs”) that may be negative.
Various people, since the book came out, have complained that How Not To Be Wrong is a leftist tract, intended to smear Republicans as being bad at math. I do not in fact think Republicans are bad at math and it sort of depresses me to feel my book reads that way to those people. What’s true is that, in “More Pie Than Plate,” I tear down an old Mitt Romney ad and a Scott Walker press release. But the example I lead with is a claim almost always put forward by liberal types: that the whole of the post-recession rebound has accrued to the 1%. Not really true!
Long intro to this: I get to polish my “calling out liberal claims” cred by objecting to this, from the Milwaukee Journal-Sentinel:
UW-Madison, the fourth-largest academic research institution in the country with $1.1 billion of annual research spending, has helped spur strong job growth in surrounding Dane County. In fact, employment gains there during the last 10 years far outstrip those in any other Wisconsin county, accounting for more than half of the state’s 36,941 net new private-sector jobs.
I’m pro-UW and pro-Dane County, obviously, but people need to stop reporting percentages of net job gains. What’s more — the reason job gains here outstrip other counties is that it’s the second-biggest county in the state, with a half-million people. Credit to the Journal-Sentinel; at least they included a table, so you can see for yourself that lots of other counties experienced healthy job growth over the decade.
But just as I was ready to placate my conservative critics, Rick Perry went to Iowa and said:
“In the last 14 years, Texas has created almost one-third of all the new jobs in America.”
Dane County and Rick Perry, you both have to stop reporting percentages of net job gains.