School communities find themselves within an overall ideological and epistemological controversy with regard to a drive for goal-oriented and "evidence-based" practices on the one hand and emancipative bottom-up developmental strategies on the other, treating empirical data as information to be analysed according to context, with potential meaning for practice. This raises questions of democratic purposes of education, of leaders' and teachers' agency and corresponding accountability. This article is therefore an empirically based discussion of the relationship between multiple understandings of democracy and multiple practices of evaluation. It presents certain results of three ethnographic research projects among school leaders in Norwegian secondary education. Using a critical ethnographic research methodology in order to build agency, the article focuses on dilemmas and paradoxes of evaluation in an era of market-driven accountability. A situated perspective has been applied in order to view evaluation as a joint enterprise dependent upon the shared vocabulary and repertoire of evaluative tools in each community of practice. The fieldwork shows that the factors that are crucial for teachers' and school leaders' agency in this professional area concern their awareness of assessment used for evaluative purposes within multiple perspectives of democracy and validity. Most participants look beyond formalised procedures and predefined purposes, focusing instead on knowledge construction. The ultimate objective of the participants seems to be that of agency building, or becoming subjects in these processes rather than objects of instrumental application.