Tuesday, November 16, 2010

Statistics Fail

image found here. source?
History suggests that if you rescale, shift, and truncate two time series, it's usually quite easy to make them look very similar. This does not mean anything at all, it's simply fishing***. The graphic is suggesting that the US is following Japan into economic deflation, which would be bad. However, this is showing a subset of inflation data (food and energy*) compared on an annual percent change scale* which is shifted by 12.5 years** and truncated before 1989/2001**, and suggesting they are somehow the same. Yeah, right.

* possibly arbitrary.
** almost certainly arbitrary.
*** Statistical jargon alert: "Fishing" is a word for the practice of looking at your data in so many different ways that you eventually find an association simply by chance, and then reporting that association as if it was what you were looking for in the first place. See also: bullshit, cheating, lying, multiple comparisons.

Found on NYT, but the source of the graphic is not clear. I sure as hell wouldn't put my name on it.
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