Saturday, January 2, 2010

Honest plotting

There are a lot of ways to fiddle with a line graph to alter the message. One common trick is to mess with the vertical axis. By rights, the vertical axis ought to go down to zero so you can see the magnitude of the line. Plenty of plotters, and a lot of plot software, set the vertical axis to start at the minimum data point and stop at the max data point. It is claimed that this shows more detail in the data. Yeah, I suppose. It also has the effect of making a very slight change look a helova lot bigger. I consider that misleading.
I notice the global warmers always blow their plots up vertically as much as possible.

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