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.
Great concept. Room to make updates. I bought it for an "all about me" featuring my daughter, who is intellectually challenged, as a guide to help family members give her the support she needs if something happens to me. I would have liked it to be refillable or wish it had a few pockets for other important information like documents.