To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
As an EMDR consultant I refer to this book all the time. It's my bible. Also there are so many new insights and nuggets ( as I trained a while ago) that has improved my skills further. Excellent once again!