I try and give a source for the different extracts, and will probably update it if new explanations arrive.
GeneralFrom The 50K report
For techies out there who geek out on methodology, the spider works like this: It crawls through all the categories, sub-categories, and sub-sub-categories listed on Amazon, starting from the very top and working its way down. It scans each product page and parses the text straight from the source html. Along with title, author, price, star-rating, and publisher information, the spider also grabs the book’s overall Amazon Kindle store sales ranking. This overall sales ranking is then used to slot each title into a single master list. Duplicate entries, from books appearing on multiple bestseller lists, get discarded.
(In our October report, we found that almost 80,000 of the 120,000 July bestsellers had since fallen off the lists to be replaced by 80,000 others.)
– 95% of the top 1,000
– 80% of the top 5,000
– 68% of the top 10,000
– 52% of the top 25,000
– 42% of the top 50,000
– 33% of the top 100,000
– 11% of the top 1,000,000
– some additional ones ranked in the 2,000,000-3,000,000 range (mostly from really specific nonfiction bestseller lists like “Renaissance Painter Biographies” or whatever.)
On Rank to Sales rankinghttp://www.hughhowey.com/the-january-author-earnings-report/#comment-233671
|Sales Rank||Sales Per Day|
Mostly, it still follows: http://www.theresaragan.com/salesrankingchart.html with a few additional data points added (like the one at rank 100) to increase curve accuracy.
Initial report (5th footnote)
Daily sales according to Amazon rank can be found in numerous places, including here, here, and here. Depending on the source, the model changes, but not enough to greatly affect the results. Keep in mind that the dollar figures and the exact sales are irrelevant to the ratio and percentages shown. Any change in those numbers impacts all books equally, so the picture of how authors are doing according to how they publish remains the same. These daily sales figures are adjustable in our spreadsheet, which contains our full data set and which we are offering at the low, low price of absolutely zilch.