Serial views

Posted to Statistical Visualization  |  Tags: ,  |  Nathan Yau

Like many, I’ve been listening to Serial every week, but I always just listened through my podcast app. So I missed this little bit from Adnan Syed way back in the second episode. He sent the two graphs above to the host Sarah Koenig. The graphs show tea price changes over time for two stores and Syed asks Koenig which store she would get her tea from. She says the first one, which has a more steady price.

Look again, Adnan said. Right. Their prices are exactly the same. It’s just that the graph of C-Mart prices is zoomed way in — the y-axis is in much smaller cost increments — so it looks like dramatic fluctuations are happening. And he made the pencil lines much darker and more striking in the C-Mart graph, so it looks more…sinister or something.

This was Adnan’s point: See how easy it is to look at the same information, but, depending on how it’s presented, come to two different conclusions about what it means? The 7-11 graph is the “innocent” graph. The C-Mart graph is the “guilty” graph. But they contain the same information.

See also: the baseline.

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