The past two decades have witnessed an increased demand for standardized documentation within the social services field. This have resulted in the proliferation, translation and attempt to use various kinds of standardized instruments to document clients’ needs and outcomes of interventions. Reviewing the social work literature on standardized instruments and providing empirical examples, this article identifies a widespread unsystematic use in everyday practice. This seriously undermines the ability to use gathered information to make reliable quantitative analyses of clients’ outcomes. Based on the concept of ‘situated standardization’ the article argues for a new direction in the attempts to standardize documentation within the social services. Rather than developing standardized instruments outside the social services context, as in current efforts, situated standardization points to the need to develop instruments from within this context. This would arguably produce instruments better suited for the preconditions of social services’ work, and therefore easier to use systematically. Thus, rather than a ‘light’ standardization, this can be described as a different kind of standardization situated in the actual work of the social services. An important implication is that standardized instruments need to be developed together with a close empirical examination of the setting in which it is supposed to be used.