We all make judgments, so why is it sometimes bad to be stating judgments? There are two types of judgments; judgments that are discriminating, and judgments that are evaluative.
Judgments that are discriminating (i.e. I prefer X over Y) reflect personal preferences and subjective opinions. They are considered judgments that are effective in terms of not projecting one’s perception as a complete conclusion.
When judgments are evaluative (i.e. This is horrible) it is stating something as a whole and objectively. It is taking the facts of a situation and adding personal preferences, values, and opinions to make it an objective truth. This type of judgment is ineffective because others may view the same situation differently, whether it is marginally different or completely different.
By being nonjudgmental in DBT terms, it is referring to evaluative judgments. By speaking in discriminative judgments, there leaves room for other interpretations and perceptions.