To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
I ordered and paid for a new book and was sold a used book that still had the used price (half of what I paid) sticker plastered smack on the front of the book where it was so stuck it left most of the sticker plus a lot of glue on the book. Disappointing.