Netflix recommendation prize overlooks established star ratings

by | Sep 21, 2009

Star rating for movies at Netflix

The New York Times has news this morning of a winner in the famous movie recommendations race: Netflix Awards $1 Million Prize and Starts a New Contest:

The company’s challenge, begun in October 2006, was both geeky and formidable: come up with a recommendation software that could more accurately predict the movies customers would like than Netflix’s in-house software, Cinematch. To qualify for the prize, contestants had to be at least 10 percent better than Cinematch.

Great, but the real problem with the Netflix star rating system for movies is that it uses five stars — whole stars only, and zero is not selectable. This gives you only five possible ratings choices.

Four stars 80% better than five stars

The tried and true standard movie critics’ star rating system, on the other hand, is based on just four stars — but half-stars are used, and zero stars (a bomb) is an option. This permits nine alternatives, a far better range than just five.

According to the Netflix system, the five stars stand for “Hated It,” “Didn’t Like It,” “Liked It,” “Really Liked It,” and “Loved It.” This leaves no option for ambivalence, which is a highly important rating. Ambivalence is so important that humanity has several universally recognized gestures to express it: the shrug, the flat expression, and the teetering hand, for example.

To solve this, I personally use three stars as my “meh” value.

But this leaves me only four or five stars as my Netflix options for films that leave a positive impression. So many movies would fall somewhere between these ratings in the traditional system. Three and a half stars is very useful value. It indicates a picture that was very, very good, but still missed the mark in some respect.

Movie critic ratings altered

Adding to the confusion, the published star ratings of movie critics are altered at Netflix to fit their five-star system. It appears that Netflix simply adds one star, so if Roger Ebert gives a movie three stars, it shows up as four stars at Netflix. Not only is this not Roger Ebert’s actual rating, but it proves that half-star ratings are important if you’re Roger Ebert, but not if you’re simply a paying Netflix customer.

If Netflix really wants to improve its recommendations, it should switch to the accepted star rating system that has stood the test of time, and conform with this universally accepted convention rather than adding an extra wheel.

Please send my $1 million check to my home in Racine.

Netflix pop-under ads

Hey Netflix — want to save a bundle of wasted ad money to help offset your unselfish cash award to me? Here’s how:

You know how you use a cookie to identify me as a current Netflix customer every time I return to your site to apply your inadequate star ratings?

Please start using that cookie to also spare me the endless Netflix pop-under ads that clutter my browsing experience all day every day, giving me angst about your brand. I’m already a customer, so please stop pitching me so incessantly.

That tip is free as a service to humankind.

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