This article reports the outcomes of research into the nature of and influences on collective working in an English secondary school. A design and technology department was studied over a 13-month period. Data collection was by interviews, observations and document scrutiny. The findings were analysed using collaborative practice (CP) analytical framework, which is joint working (collaboration) on a defined main task (primary task) that has both present and future dimensions, in a manner grounded in reflective practice. During the research period, the department was required to make changes to improve pupil outcomes and it was subject to other organizational influences. The analysis confirms the utility of the CP analytic framework for understanding organizational processes in educational settings; develops and substantiates the importance of the primary task and the way work-group members interpret it; and develops the significance of collaboration and reflective practice in relation to the normative primary task in the CP analytical framework. (Contains 1 table and 1 figure.)