Monday, January 18, 2010

Just because it looks like a "trend line" doesn't mean...

I've been critical of trend lines before.

The ones used by the ABS have particular problems.

But try this one on for size:

Note that the "trend line" ends the series going down.

But squint and look at just the purple line and it is apparent the series is broadly going up.

Possum says it is an "utterly ridiculous 4th degree polynomial curve".

Useful for Andrew Bolt who published it here to make it look as if global temperatures were not increasing.

He is up to other tricks as well and Possum is on to him.

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