Amazon calculates a product’s star ratings based on a machine learned model instead of a raw data average. The model takes into account factors including the age of a rating, whether the ratings are from verified purchasers, and factors that establish reviewer trustworthiness.
I bought this book for my husband as a gift. We cycle every weekend on "rails to trails" paths. He loved this book. It gave maps & directions of many trails in Southern New England; we live in MA. He couldn't be happier!!