Wednesday, February 17, 2010

ChartJunk Redux

You'd think The Business Insider' Chart of the Day could get it right but they have fallen prey to the evils of Chartjunk:
Read more below:

The latest data from comScore says YouTube served 12 billion video views during November, up 137% year over year. Unique visitors to the site are strong as well, up 32%. Even more impressive, YouTube is clobbering the competition. The next nine most popular sites combined only served up a quarter of the total views in November that YouTube served. Their growth is slower too, year over year, they've grown 86%.
Now look at the chart:
Yup. Looks like a stacked area chart until you examine the text and see that YouTube did 12Bn views, up 137%. Those numbers aren't stacked at all. Those areas are actually layered front-to-back.
I took the numbers as best I could from the graph and made a few of my own quickly.

1. Repeat the bad graph for comparison:

2. The least ambiguous would be to NOT use an area chart:

3. Here's what a proper stacked area would look like (Note YouTube goes from 4 to 16 for a total of 12):

4. If they HAD to use layered areas, a little 3D should have been included to make it understandable:

Graphics are meant to inform. "A picture is worth a thousand words." If a few hundred words are needed to explain the graph, then the graph has failed. There should be no misunderstanding as to what the "artist" is trying to say. Let's pick on them a little more.

I. Which kind is this? Stacked or layered?

Layered. You can tell by the way Online Services crosses over Entertainment and Devices. So that means Office profits are 8Bn instead of the 3Bn difference..

II. Stacked or layered?

This one is stacked. They helpfully give you the numerical trends. With a little interpretation and subtraction, you can verify this is stacked.

III. Stacked or layered?

Okay, that was easy ! Of course, three-quarters of the information is hidden by the layers themselves ... Google is, of course, insignificant, if you read this graph.

IV. Stacked or layered?

Stacked, but the only way to know that is to look at the iPhone and realize that it came out in early '07 and so it doesn't show up (green) until then.

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