Friday, May 26, 2006

This Graph Needs a Polygraph

As I mentioned earlier, I asked the students in my economic statistics course to do presentations on graphs or tables from print media. Here’s another gloriously misleading one, found by Scott G. in the May 2006 issue of WIRED magazine. It’s from an article titled, “The Digital Music Blues.” The graph is supposed to demonstrate that, in spite of the growth in legal music downloads, illegal downloads are still cutting into the record industry’s bottom line.

Notice how only a tiny 1% of iPod capacity is filled with legally purchased iTunes songs! I guess the remaining 99% percent must all be illegal downloads, right? That’s certainly the implication of the accompanying article: “What’s filling all that excess capacity? Well, despite the efforts of the Recording Industry Association of America, nearly a billion songs are traded on P2P networks every month.”

I checked my own iPod, and sure enough, the songs I bought on iTunes account for only about 1.5% of the 20GB memory. What’s filling the rest? Turns out 62% of it is filled by, um, nothing. I just haven’t filled it yet. The other 36% or so is almost entirely filled with music I ripped from my own legally purchased CDs or those of my relatives.

(Did I mention that most of the data for the WIRED article came from music industry sources?)

I showed this graph to one of my colleagues, and he sheepishly confessed that a mere 25% of his university-provided SanDisk USB memory key is filled with work-related documents and data files. I’m mighty suspicious about, you know, how he might be filling the rest of that memory key...

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