Some examples of a claim of value would be saying that something is immoral, claiming something is wrong, or stating that something is worse or better than something else. A claim of value is a statement in which something is lauded as good or decried as bad.
A claim of value is not based on factual information the way a claim of fact is. Rather, it is based on opinion. Morality or the "goodness" or "evil" of a thing cannot be quantified or measured, meaning that assertions to that effect cannot be based on data.
Typically, claims of value survive by consensus, with the majority of a population agreeing that certain acts, behaviors or items are either "good" and should be kept or "bad" and should be discarded.