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.
I worked in the Emergency Department as a senior Registered Nurse for over ten years, so I know that there are some entertaining stories to be had. I was expecting some laughs. What I got was a rant against the NHS and no real stories. Didn't bother to finish the book and wouldn't buy this author again.