08 May 2009

The third derivative of the employment rate is positive

The third derivative of the number of people employed in the United States is positive. (From 538.)

Nate Silver puts it as "the second derivative has improved", but let's face it, this is really a statement about the third derivative. Compare Nixon's 1972 statement that the rate of increase of inflation was decreasing, which Hugo Rossi pointed out in the Notices was a statement about the third derivative. (I seem to recall John Allen Paulos pointing this out in one of his books, but I don't recall which book and therefore can't date it relative to Rossi's letter in the Notices.)


Eric Tassone said...

I propose we all use this occasion to try to bolster the popularity of one name for the third derivative, "jerk: http://en.wikipedia.org/wiki/Jerk_(physics) Or perhaps its alternative name, "lurch". :-)

Anonymous said...

Eric, "jerk" is most definitely not synonymous with "third derivative". It's the third derivative of position. It's the second derivative of velocity, and the first derivative of acceleration. But since this application has nothing to do with mechanics, jerk doesn't enter into it.

Except maybe as applied to people who point out proper usage.

Søren said...

You can tell how bad the economy by the order of the derivative they have to use to give a positive statement.

g said...

I've read the Nixon quote in "Innumeracy: Mathematical Illiteracy and Its Consequences".