A new tool for political pundits - eBay?

In keeping with the fine traditions of this blog, where we use eBay trends to predict sports results (and occasionally eat crow), I'm attempting to answer the question - were purchases on eBay leading up to the 2006 mid-term elections an indicator of overall US voter sentiment? 

Andy Veluswami, one of our resident marketplace analysts and math gurus, has the answer – "consistent with pre-election polls done by Pew, USA Today, CNN, Fox, ABC, Newsweek, and AP-AOL, and the election results themselves, the eBay "Blue Index" shifted resoundingly upwards - nationwide, and in most individual states."

In other words, Yes.

To get to this answer, Andy and his team examined all Political Party-affiliated purchases made on eBay for both Democrats and Republicans during the month of October 2006, and created a "Blue Index." They compared the Democratic share of the total number of party-affiliated items purchased (both Democratic and Republican) with the share from two years ago, just before the 2004 general election.

As you can see from this picture, there was a significant increase in the purchase of Democratic Party related purchases. The graph shows the shift in the "Blue Index" for the 25 most active states on eBay in terms of political-party affiliated purchases. Click on the graph itself to bring up a larger version.

(Incidentally this would work just as nicely with a "Red Index" – the graph would just be inverted).

Andy explained some considerations in the team's methodology: A Democratic-party affiliated item was any item that had the word "Democrat" in its auction title (and did not contain the word "Anti") - such as this "Kiss me, I'm a liberal" t-shirt. A Republican-party affiliated item contained the word "Republican” and not the word "Anti", such as this handsome GOP necktie. Items containing both words "Republican" and "Democrat" were filtered out. Around 17,000 listings that were live in October 2006 were examined.

Admittedly, the model isn't perfect, but we'll probably try it out again for the 2008 Presidential Election… stay tuned!

I went to take a picture of Andy for the blog, having ascertained that that there was a nonzero probability of finding him in his cube. He looked over my blog post, and had this to say:

"I'm Andy Veluswami, and I approve this blog post."