Those who diagnose, observe, by means of distinctions, which then enable statements about the functional methods or characteristics of the client’s system. Popular guiding distinctions are possibly healthy/ill, successful/unsuccessful, dexterous/clumsy, useful/harmful, positive/negative and many more.
What is important here is that each of the distinctions requires a factual, social or temporal reference point, e.g. in which regard is it positive/negative? For whom is it useful/harmful? When is it successful/unsuccessful? What is right for quality, however, is possibly poor for the returns, what is good for one, is not good for another, and what appears, initially, to be healthy or successful, later reveals itself as sick making or a failure (or everything the other way around).