There seems to be an assumption that an enhanced scientific foundation, in form of an application of research results, leads to better quality in schools and also to better student outcomes. The objective in this article is to explore how this demand can emerge in an action research project as well as in school principals' daily life. This is done in form of a case study were a group of principals enters a partnership with a researcher in their quest to apply a scientific approach in their own and, in their teachers' professions. This study provides a pertinent example of how this demand can emerge in practice. The theory of practice architectures (Kemmis & Grootenboer, 2008) is used as an analytical framing. The research questions are as follows: 1) How do the principals understand and realise the demand of a scientific approach in their roles as pedagogical leaders? 2) What happens when a group of principals and a researcher enters a partnership? 3) What practice architecture affect the partnership between the principals and the researcher? 4) What practice architecture affect the principals' pedagogical leadership actions in their schools?