This paper considers two linked questions: firstly, what are the effects of teacher collaboration?; secondly, what research methodology is required to prove these effects? Schools are presumed to be the most significant places for teachers’ professional development, and teacher collaboration is often seen as a powerful learning environment. Nevertheless, little research exists that describes the characteristics of teacher collaboration and the factors which spur this collaboration (Sawyer & Rimm-Kaufman, 2007). Furthermore, the outcomes of such collaboration are not well known and could be contradictory. Through deep interviews with six teachers, Meirink et al. (2007) discovered that these effects address mostly teachers’ conceptions. Conversely, drawing on findings from a large European project, Hansen (2008) argued that specific types of workshop impact directly on teachers’ practices. However, Trumbull, et al. (2006), examining over three years the conceptions and practices of two teachers in a collaborative project, showed that conceptualization about learning and teaching strongly influences teachers’ approaches and practices. Overcoming these oppositions, Lam and Kember (2006), in a study of eighteen secondary school art teachers, showed both the relationship between conceptions and approaches to teaching, and the influence of contextual factors including both teacher’s experience, and the climate and organization of the school. In line with these results, Andrews and Lewis (2002) –through interviews, focus group discussions and observations– found impacts on action in the classroom when the school organization allows teachers to share understandings through professional learning activities. This overview suggests a central question: what kind of conceptualization could result from teachers' collaboration and transform their practices? To tackle this question, Grangeat and Gray (2007) referred to frameworks based in activity theory. They concluded that professional activities are underpinned by a cognitive and operational structure –called an operative model– which is organized along critical dimensions. These dimensions gather the goals and the repertoire of actions which actors use to achieve their projects. Such operative models change with experience. Through overcoming new problems, conducting professional discussions, and interacting with numerous partners, actors’ operative models may move to deeper and more extended modalities of organization (Grangeat, 2008). Actually, actors’ operative models are mostly embodied in professional activities, and are not usually made into objects of explicit representation (Stevenson, 2001). But teachers are accustomed to reflect and to discuss their thinking and practices. Thus, eliciting teachers’ operative models could enable us to learn more about the processes which determine the transformation of their practices.

Empirical data consist of 96 semi-structured interviews with teachers of primary and secondary schools (age 8-15). Interviews are audiotaped, transcribed and analysed with Tropes (similar to NVivo). A first analysis –drawn from the corpus as a whole– suggests a common operative model (COM) organized along five dimensions: teaching core, learning processes, teaching temporalities, teacher reflective activities, and professional environment. Each dimension gathers a set of actions: e.g. “teaching core” consists of addressing specific contents, enacting learning activities, and recognising each pupil as an individual learner; “professional environment” consists of attending to formal and informal exchanges, interacting within department and school teams, and building projects with community partners. A second analysis provides a score to each interview according to the way each teacher makes explicit the COM dimensions and actions. Two variables could explain the score evolution: length of experience through teacher age, and teacher engagement within professional networks.

An analysis of variance shows that teacher age affects the score: 35-45 years old teachers obtain significantly better scores (F=8.22; p<.0001). Nevertheless, teacher engagement is the strongest factor: regardless of age, teachers implicated within collective projects obtain the best scores by a significant margin (F=11.31; p<.0001); this difference is also true for the four COM dimensions (no measurable effects on “teacher reflective activities”). Consequently, the study shows, across a broad sample, that teacher engagement within professional networks increases the range of teaching situation components which are considered by teachers. This study is in line with other enquiries, often qualitative, or case studies which show the effects of: reciprocal peer coaching (Zwart, et al., 2007), exchange about classroom video (Wong, et al., 2006), etc. This study is also supported by enquiries which show that collaboration helps teachers to enact deeper thinking about their work in the classroom (Parsons & Stephenson, 2005).