Per DerbyDad03:
How do you use the 5 Star rating system to make a decision?

Do you have number, such as 80% 4? or above with 70% being 5?, or
something like that?

I missed the point of the OP first time around....

I look at the Amazon reviews a couple different ways.

First thing, I look for 4-5 stars average.

then I select the low reviews (1 and 2 stars) and read through some of
them - trying so spot some quality or basic design issue.

Then I select all reviews and look for situations where shills are
posting fake positive reviews - there's a certain feel to the
descriptive language that will make me conclude it's a fake review.
--
Pete Cresswell