Really great point. Slightly off topic, the standard for rating systems seems to be 5 stars, but I prefer 4 star systems because they force you to make a +/- choice with no cop out ambivalence choice. I'd be curious to see the same distance work applied to a four star system.
So you are forcing people who are neither in favour nor against something to produce false pro/contra votes. There are some cases where this strategy makes sense like questions about controverse topics. Other than that it produces noise. In my experience, the debate 4 vs 5 options often has more to do with the authors' personality and training than anything else. Surprisingly little is based on solid, non-ambiguous evidence.
Using 4 points instead of 5 merely removes some of the inherent ambiguity, the results are still likely to organize around similar concepts.
For many things, most people don't bother to think about the difference between crap unless you force them to, so in a 4-star system 2 stars becomes the "mediocre" rating while 3 and 4 differentiates between the good ones. How many people really care about a grade difference between D and an F? Likewise, do people really spend that much time making sure their 1 and 2 star ratings form a consistent philosophy of relative crappiness?
If "forcing" people to make a choice about something that is supposed to be a subjective categorization to begin with is probably not helping anything. If you want to force a like/dislike you should get binary data and be done with it.
"Would you eat this? Yes/No."
That's easy to answer accurately. Everyone will agree on what you mean. If you haven't answered that means you don't have an opinion. Beyond that semantic ambiguity is impossible to avoid and gets worse the more numbers you add.
