Filter ratings and reviews based on if the rater has read the book(s) or not

Most movies and tv shows are based on books. And many people who review or rate a certain movie/show base their rating/review on how true it is to the book, especially if they're big fans of the book. You all know that LOTR fan who hates the movies because e.g. Tom Bombadil isn't in them, or the bigger role of Arwen.

Personally I wish I could separate ratings from people who have read the book from those that haven't, like I can from gender and age. I think both cases are interesting but I also think that bunching them together can skew the rating.

One example recently is Foundation. I haven't read the books and don't plan to, but 95% of all reviews are from what another reviewer called "book purists" who give a low rating because it apparently deviates so much from the source material.

I use iMDB ratings as some kind of crowdsourcing guide because there's just too much to watch nowadays to find the time to watch a couple of episodes before judging if it's worth to continue watching or not. I've set my limit at 8. I've tried a few shows that seem interesting with a lower rating but very very rarely I like them so I have found an iMDB rating of 8+ to be a very good filter.

Foundation has been on my watch list but the rating (7.5) is too low for me, but I also understand that that rating includes so many book comparison ratings.

IMDB should add an option when you leave a rating or review to also tell if you've read the book something is based on. I think this would interest both the book purists and those who don't care whether something is true to the book or not.