Thanks to author feedback from authors with access to Amazon DTP (Digital Text Platform) and thus real-time sales numbers for Kindle books, I was finally able to add more accurate sales estimates for Kindle Books. This includes tracking up to three sales per hour. For Kindle books selling as frequently as 7 books per day, the accuracy is up to 95% for sales estimates. For Kindle ebooks selling 30 or less per month, accuracy should be closer to 98%.
There is still room for improvement, but previously NovelRank’s accuracy was at 78% for books selling 3 or more per day or more specifically, multi-sale hours. Unfortunately, I don’t have the time to retroactively run sales history through the new formulas, so the accuracy is improved as of today moving forward. In all cases, including the future, NovelRank is underestimated book sales estimates on Kindle Edition books. I feel this is a better route that overestimating sales by 5%. Better safe than sorry.
Thanks again for the great feedback from authors to improve the accuracy of NovelRank book sales estimates on Amazon Kindle books.
Update: May 30, 2010 2:01am MDT
The new formula has been retroactively applied to all Kindle books tracked prior to 5/1/2010. You may notice slightly different sales numbers for your Kindle Edition books than you did previously.