Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases.
Chilling, well-written and very informative. The subject material appears very well researched providing the lay-person some insight into the darker side of our species. Also provides a wonderful sense of the kind of very clever work done by criminal profilers.