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PPI data — Fun with Statistics?

Posted By Barry Ritholtz On November 16, 2005 @ 8:55 am In Inflation | Comments Disabled

Mike Panzner [1] looks at the spread between the PPI and the nonsensical core rate:

Over the past three decades, the spread between the monthly year-on-year reported and "core"(ex-food and energy) Producer Price Index data, while volatile, has steadily widened.

As a matter of fact, the differential hit a multi-decade high of 4.3 percentage points in September, and was only marginally below that level in October (as reported this morning).

In other words, the series that is supposedly more representative of the underlying inflation trend — the "less volatile" number that government officials insist we focus on — seems to be lagging further and further behind the headline statistic.

By one whole percentage point, I reckon, if you draw a simple trendline through the 12-month moving average of the differences over the period.

Spread: Reported and Core PPI
click for larger graphic

Ppispread [2]


Panzner notes:  "Maybe I’m too cynical, but do you think somebody’s having a bit of fun with (government) statistics?"

Article printed from The Big Picture: http://www.ritholtz.com/blog

URL to article: http://www.ritholtz.com/blog/2005/11/ppi-data-fun-with-statistics/

URLs in this post:

[1] Mike Panzner: http://www.amazon.com/exec/obidos/ASIN/032124785X/ref%3Dase%5Fthebigpictu09-20/103-1397101-9255814

[2] Image: http://bigpicture.typepad.com/.shared/image.html?/photos/uncategorized/ppispread.jpg

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