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 work at a school and am reading this book as part of a parent book club. The club meets once a week and we read sections together. We have homework and discuss using a variety of strategies. My participation rate increased from about 12 parents to 35.