Probably the biggest German site for indie authors, Die Self-Publisher-Bibel, recently did an extensive test of sales rankings on Amazon with books published deliberately for that purpose. They wanted to test three basic assumptions about sales algorithms used by Amazon:
– Price influences sales rank
– Enrolling in KDP Select influences sales rank
– The dynamics of sales influence sales rank
The results are eye-opening. Fortunately, they have also published an English version on their site. I highly recommend it to anyone involved in self-publishing:
http://www.selfpublisherbibel.de/test-how-amazons-algorithms-really-work-myth-and-reality/
Ruth Nestvold - Indie Adventures 