Netflix is oversimplifying their personalized rating system – going from the more flexible five-star system to a simple ‘thumbs up/thumbs down’ system.
Their rationale is that what I see on my screen might show five stars , but might show as one star on the screen of someone else who has radically different tastes.
The new system removes the possibility of a three-star review (I liked it but not necessarily enough to want to see more – to be judged on a case by case basis) to a black/white system that wants me to say either I love this and I want more, or I hate this and never want to see anything like it ever again.
Both the new system and Netflix’s rationale (along with an introductory video) follow.
Goodbye Stars, Hello Thumbs
At Netflix, our goal is to connect you with great stories. Every Netflix member has unique tastes and we’re constantly working to improve your personalized suggestions so you’ll find something great to watch as quickly as possible.
Today we’re changing the way you can tell us which stories you love, and which ones you’re just not that into.
We are retiring our five-star rating system and replacing it with a simpler and more intuitive thumbs-up and thumbs-down. A thumbs-up tells Netflix that you like something and want to see similar suggestions. A thumbs-down lets us know you aren’t interested in watching that title and we should stop suggesting it to you. You can still search for it, but we’ve heard what you were trying to tell us — you aren’t a fan — and it will no longer show up on your homepage.
In either case, using thumbs helps us learn even more about your unique tastes so we can do a better job suggesting stories we think you’ll love.
The star rating you see next to each title is being replaced with a personalized % Match score. This score is a prediction of what Netflix thinks you may enjoy watching, based on your own unique tastes. The % Match is based solely on our algorithms analyzing your individual viewing habits and behavior — it is not a measure of overall popularity across the service.
Netflix has had star ratings for much of our history, but we’ve learned through over a year of testing that while we’ve used stars to help you personalize your suggestions, many of our members are confused about what they do.
That’s because we’ve all gotten used to star ratings on e-commerce and review apps, where rating contributes to an overall average, and the star rating shown next to a restaurant or a pair of shoes is an average of all the reviewers. On those apps, being a reviewer can be fun and helpful to others, but the primary goal isn’t always to help you get better suggestions.
In contrast, when people see thumbs, they know that they are used to teach the system about their tastes with the goal of finding more great content. That’s why when we tested replacing stars with thumbs we saw an astounding 200% increase in ratings activity.
For members who have provided star ratings in the past, we will continue to use that information to suggest great content.
The more you teach us about your unique tastes, the better job we can do suggesting your next great binge-worthy show or that perfect title for movie night. So the next time you find your new Netflix obsession, give it a 
.
-Cameron Johnson, Director of Product Innovation