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 analyzes reviews to verify trustworthiness.
A great little data primer, but in the next edition I would like at least a paragraph on the condition of our aging underground pipes, and a whole page on how to manage fracked water safely. All American citizens deserve clean water.