Monday, August 10, 2009

The Amazon Best-Seller List: “A Black Box with the Fancy Word ‘Algorithm’ Used to Describe It”

There’s been some speculation lately about what online book-seller Amazon’s best-seller lists (“updated hourly”) do or don’t mean. At The Big Money, now, there’s a new article by Marion Maneker that takes a closer look at the charts.

On the method used to compile the list, for instance, Maneker quotes “an Amazon spokeswoman”:

“We base rankings on all-time sales, as well as recent sales that are weighted more heavily than older sales, so that our lists are timely and aren't always dominated by all-time best-sellers like Harry Potter.”

Maneker also provides a quote from author Andy Kessler’s book Wall Street Meat that explains what this may mean in practice:

"I'm not sure the exact number," Kessler says of the weightings, "but my guess is 40 percent hour, 30 percent day, 20 percent week, and 10 percent month. So if you have a huge spike in sales, you don't completely dislodge books that have been in the top 10 or top 100 for months and months. Though you might pass them for a very fun hour."

Based on these assumptions, Maneker goes on to speculate on the numbers required to get on the list:

At the very top—rankings No. 1 to No. 10—a book could be selling 3,000 to 10,000 copies a week through the Internet retailer. So all it takes is, say, 500 to 1,000 copies manhandled through the system on a single day to get your book into the top ranks.

I’ve suspected the same thing, but in the end, it depends on how exactly the list is assembled, of course.

The complete article, which also discusses some of the implications for authors, ways of gaming the list and the impact of e-books and the Kindle, is well worth a read.

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