Does "criticism" imply positive as well as negative?
I thought I was always taught at school that criticism meant evaluation and opinion, either positive or negative. These days, it seems criticism, or to criticise, is almost exclusively used to mean negative commentary. Dictionaries seem to acknowledge both variations, but has there been a semantic shift in the words recently, and what is the usual meaning?
Wikipedia, for example, has many Criticism sections which are generally a list of negative opinions. Whilst I know they are discouraged for this reason, would they semantically be better named Negative Criticism sections? On the other hand, a film critic is still assumed to give as many positive reviews as negatives, so this would seem inconsistent.
I don't think there was a recent shift; there are words with two distinct meanings, one of which is more used and therefore requires little or no context and the other, more rare which requires context to be established before the less common meaning of the word can be used to refer to something.
This is exactly an example, etymonline shows word critic in use since 1580s, from "one who passes judgment," but gives the warning that "the English word always had overtones of 'censurer, faultfinder.'"
Macmillan list these two distinct meanings:
someone whose job is to write or broadcast their opinions about things such as books, movies, or plays
someone who does not like something and states their opinion about it
As for "Negative Criticism" it does, for me, and taken out of context, bring a bit of a pleonastic smell to the phrase; however I don't object to "Positive Criticism".
In regular use I would use "criticism" to refer to "negative criticism", however in names of sections, especially if "Positive Criticism" closely follows or precedes, then "Negative Criticism" sounds pretty justified to me (it also emphasizes the fact that you use the word criticism as neutral, so the text should be consistent with that, too).
In practice, "criticism" is probably 80 percent negative. So your impression that it is rarely positive is correct.
However, you are also correct that criticism can (and occasionally is) positive. Book, restaurant, theater and fashion critics are known to praise work that they evaluate.
If you want to stress the idea of criticism being neutral or positive, you can ask for (or refer to) "constructive criticism," which generally means positive, or you can use the term "critique," as Tim Rogers mentions above.