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.
This is a review for the format, which is cumbersome and makes it hard to read as an ebook. This isn't really an ebook, more like purchasing a locked PDF as the reader is not able to toggle the font or spacing for easier visibility. Each page shows up in its entirety and you have to zoom to sections of the page to read if you don't have a screen large enough to accommodate the full page to read at a comfortable font size.
I was looking forward to reading the updated sections, but now I will purchase a used, older version to review planning concepts. Wish I kept my old one from school!