Jim hit on the head. Stars are ubiquitous because they're ubiquitous. People expect them, and they're deceptively simple.
It's hard to capture what a rating actually means. Take a simple thing like, "Rate this movie from 1 (lowest) to 5 (highest)." What does that mean? Does it mean "Rate the quality of this movie?" or does it mean "Rate how much you enjoyed this movie?" There's plenty of movies that are obviously well made, well acted, and of undeniably high quality, that I simply just don't like. Similarly, there's plenty of crap movies that I enjoy immensely. How do I rank these? Sure you could have two different scales, but as soon as you add a second, you're quickly going to want to add a third and fourth, until the rating system becomes overwhelming. Even a Likert scale doesn't mean the same thing to users. There's plenty of users that rank everything 5 stars, others that rank items only 1 star or 5 stars. Even in my own experience a Likert scale can be problematic. I decided to rate all my songs on iTunes. I decided I'd try to bell curve it with: 1: absolute crap, or non music track 2: don't like it 3: perfectly acceptable 4: like it 5: sublime This worked for a while, until I started to realized that there would be two songs that I liked, but weren't sublime, but I preferred one to the other. I couldn't capture that relationship. In a sense, a 7 point scale would have been better here, but I suspect I would have ended up with wanting a 9 point scale. Typically, people just use a 5 point Likert scale and tell users, "do what you want with it" and then renormalize the rating across all the users before doing something interesting with it. Personally, my experience with Likert scales has made me appreciate the simple "thumbs up"/"thumbs down" approach Tivo has taken. :) -- Jonathan Koren [EMAIL PROTECTED] http://www.soe.ucsc.edu/~jonathan/ ________________________________________________________________ *Come to IxDA Interaction08 | Savannah* February 8-10, 2008 in Savannah, GA, USA Register today: http://interaction08.ixda.org/ ________________________________________________________________ Welcome to the Interaction Design Association (IxDA)! To post to this list ....... [EMAIL PROTECTED] Unsubscribe ................ http://www.ixda.org/unsubscribe List Guidelines ............ http://www.ixda.org/guidelines List Help .................. http://www.ixda.org/help
