This article is a report on a clinical intervention relating to an activity (Clot, 2008a) aimed at supporting pilot teachers (PT) of a method of analyzing work in their educational establishment. The intervention consisted, over a period of three years, of getting a group of six PTs working to develop their power to act in the workplace. More precisely, they were engaged collectively in an analysis of their activity as pilots, based on videos taken while they led sessions on the method. From the research point of view, there were two goals: first, to face the methodological challenge of exploiting traces of the group’s activity and analyze the group dynamics; second, to question the circumstances in which such an intervention constitutes a development opportunity for PTs by reinforcing the legitimacy of the professional questions that they ask themselves and the answers that they give in the workplace.