The focus of this thesis is the factorial survey approach as a method for studying professional judgements in social work. The factorial survey approach, which was first introduced in the social sciences around the beginning of the 1980s, constitutes an advanced method for measuring human judgements of social objects. At the general level, this quasi-experimental approach involves presenting respondents with fictive descriptions of social objects (vignettes), in which selected characteristics describing the objects to be judged are simultaneously manipulated.