Quote:
Originally Posted by Fbone
I'd also like to know why he still believes the day's bestseller sells 7,000 copies.
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Amazon Ranking is not an exact number but rather a rolling average for several days. That is one of many reasons Data Guy reports ratios rather than absolute numbers. The other being that absolutes aren't useful to the goal of measuring change in the industry because of their longer term volatility, especially with BPH titles spikey launch windows.
Remember, DG works with hundreds of thousands of titles across different categories to categorize the market, not individual titles. As is, the rolling average reduces the report's volatility. If nothing else, because it takes time for the spiders to crawl.
That said, one thing that came out from external criticism of the methodology last time out is that the sales profile at Kindle is changing from last year; sales for top sellers are remaining constant over time but midlist sales are growing so that where last year a title needing say 200 sales a day to hold ranking it now needs 210 or 215. (This was pointed out by a respected analyst that goes by the name of Phoenix. It was fun watching her and DG chat on that.) It was acknowledged that that part of the model needed tweaking but it would... complicate... comparisons across quarterly reports. It doesn't impact the top sellers or the purpose of the reports but it is an issue at lower levels or when comparing individual title sales over time. Which isn't a target of the reports.
That is, of course, what I get out of the methodology description and the comments and questions I've seen.
You can always get a better one from DG himself (or herself) at AE. Comments are welcome and questions answered fairly quickly.