Honestly, that's a useless metric. Since banning incentivized reviews, the situation is actually _worse_ than it was before.
All of the vendors who were sending out products for incentivized reviews now reimburse reviewers after they buy the product and leave a review, which means the review gets a "Verified Purchase" tag. This is against the rules, but it's happening.
In the age of incentivized reviews, those reviews did not have a "Verified Purchase" tag.
Source: Used to be an incentivized reviewer (stopped after rule change).
I don't think there's really a solution at all. As long as people are free to do outside deals there's always going to be review manipulation.
The one thing that could help this is Amazon getting rid of third party sellers or go the route Target announced today and only partner with trusted companies.
Does anyone know why they don't do this?