Source was copying all 319 reviews into a text file and working forward with that. Analysis with Excel, Presentation with Powerpoint - not a lot more to it than that, but what we discovered is that the system was gamed by altering a non-existent attribute for the product in each review - the product color.

Each pseudonym would use a random number as a color choice, and no pseudonym repeated the choice so that each identity could post 50 or more reviews.

There were three confirmed-purchase reviews, one of which was critical (and doesn't show up on the main product page when you sort for review stars). All of this points to serious flaws in Amazon's review-filter algorithms.

Here is the actual product: https://www.amazon.com/ELYAN-Digital-Thermometer-Function-Grilling/dp/B07GVJGYRR/ref=cm_cr_srp_d_product_top?ie=UTF8. I didn't want to make it about a single set of reviews since the problem is so widespread.