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I'm surprised this article, nor the discussion here doesn't address the main issue here: Just because you use numbers doesn't mean your data is quantitative. S

I'm surprised this article, nor the discussion here doesn't address the main issue here: Just because you use numbers doesn't mean your data is quantitative. Star scores are an attempt to map a qualitative experience (enjoyment of the film) with some quantitative measure. Which is fine if you just want to get a sense of 'how much' somebody liked a something. If I say I give scotch A a 5 scotch B a 3 and scotch C a 4 then you know that I like the scotch's in A, C, B order. It's a short hand way to express my personal ordering of qualitative experience, just like we use the words: 'good', 'better', 'best'. The problem is this data is not really numerical, so even basic mathematical operations don't make any sense. When we add 2 heights, 2 masses, 2 speeds etc the result makes sense. But not so with ratings. Even basic difference doesn't make sense, is the difference between 5 and 4 stars the same as between 4 and 3 stars? There is no 'unit' distance in scoring system. So doing any sort of averaging is just going to give you nearly meaningless results.

godDLL 14y ago
Ah, the top-sense comment is the third one from the top. :) A store that is also a movie theatre could do away with numeric representations by just watching what the users are doing with it's content. Things like "did they finish watching the movie?" or "did they get through the whole thing in one sitting?" could be helpful. Not to mention you can actually see if those titles were being watched again or not. But there's still the problem of how to communicate the findings to the user, or formulate them.
YokoZar 14y ago
I've had this intuition as well, and tried to put it to use when redesigning the Ubuntu Software Center's ratings system. Ratings are fundamentally ordinal data -- higher is better, but the difference between 4 and 5 is not the same as the difference between 3 and 4. This implies that the arithmetic mean is a broken concept, however the _median_ should still survive intact. I thought about ways to implement this in Software Center, however I'm still not quite sure what a good algorithm for ordinal rating data would look like. Please feel free to post ideas on this stackexchange question: http://stats.stackexchange.com/questions/19115/how-do-i-sort-an-ordinal-list-of-user-generated-ratings-data http://stats.stackexchange.com/questions/19115/how-do-i-sort...
stewbrew 14y ago
Such data is called ordinal (see https://en.wikipedia.org/wiki/Level_of_measurement#Ordinal_scale https://en.wikipedia.org/wiki/Level_of_measurement#Ordinal_s...). You could use arithmetic means etc. if the distance between the categories were equal. Unfortunately, nobody defined what 1, 2, 3 ... stars mean.

godDLL 14y ago

Ah, the top-sense comment is the third one from the top. :) A store that is also a movie theatre could do away with numeric representations by just watching what the users are doing with it's content. Things like "did they finish watching the movie?" or "did they get through the whole thing in one sitting?" could be helpful. Not to mention you can actually see if those titles were being watched again or not. But there's still the problem of how to communicate the findings to the user, or formulate them.

YokoZar 14y ago

I've had this intuition as well, and tried to put it to use when redesigning the Ubuntu Software Center's ratings system. Ratings are fundamentally ordinal data -- higher is better, but the difference between 4 and 5 is not the same as the difference between 3 and 4. This implies that the arithmetic mean is a broken concept, however the _median_ should still survive intact. I thought about ways to implement this in Software Center, however I'm still not quite sure what a good algorithm for ordinal rating data would look like. Please feel free to post ideas on this stackexchange question: http://stats.stackexchange.com/questions/19115/how-do-i-sort-an-ordinal-list-of-user-generated-ratings-data http://stats.stackexchange.com/questions/19115/how-do-i-sort...

stewbrew 14y ago

Such data is called ordinal (see https://en.wikipedia.org/wiki/Level_of_measurement#Ordinal_scale https://en.wikipedia.org/wiki/Level_of_measurement#Ordinal_s...). You could use arithmetic means etc. if the distance between the categories were equal. Unfortunately, nobody defined what 1, 2, 3 ... stars mean.