And What’s Wrong with This Picture?

I accidentally hit a site that is promulgating this graph; not the first time I’ve seen it.
Note that it’s perfectly true, and that the vertical scales and start and end points have been carefully chosen to yield a misimpression. Does this constitute lying? To a political or legal mind, I think it doesn’t.

(Update: also note that the two curves have different time filters applied. Consider why this would be so. Hint: it is related to the choice of vertical scale.)

In a blog comment exchange here, I casually mentioned “cherry picking” and “Ted” elaborated:

The summary reference to “cherry-picking” says a lot. What it illustrates, more than anything, I think, is the different sorts of argument that count as acceptable in science and in political discourse.

In science, the assumption is that it’s not okay to treat evidence selectively. You’re supposed to *try* to account for all the evidence.

In political discourse, I’m afraid, the de facto assumption seems to be that it’s fair to pick up whatever data point happens to be handy and throw it at your opponent, while (of course) ignoring and evading the data points they throw at you.

George Will’s recent column was an excellent instance of what happens when you take the norms of political discourse and apply them to science. Will may have thought he was just “spinning” — which is more or less what he gets paid for — but he was spinning a topic where “spin” counts as culpable distortion.

Update: Here’s the same data without the three bugs. Consider plotting the above graph for 1996- 2006 instead of 1998-2008.

Stop the presses, huh?

See also How to Tell Different Stories with the Same Data.