Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases.
When I made a couple of the projects e.g the Aurora Pillow being the first one, following the instructions to the letter with the correct 3mm rope, the pillow size turned out to be more of a throw cushion 30cm x 30cm than a pillow. An approximation of what the finished size would be should [in my humble opinion] be included in the introductory paragraph. The above also applied to the Riley's Rug. For inspiration, the book is OK. But only just.