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.
My boys love these books. I ordered the set to replace our current overly loved books. I was disappointed that the set was not all board books. My one year old is not very gentle so I can't keep them on their book shelf.