The assessment in child welfare raises a number of questions. Number of work in this area focuses on the issue of tools. This paper presents an approach based on collective development process, the working team. Four situations have been studied extensively in the context of action research. The analysis focused on the collective working time (meetings) and helps to highlight the influence of organizational framework, the importance of sense of security and ways of proceeding that may limit the quality of evaluations. Improving the quality of assessments cannot rely solely on tools: it also depends on the quality of teamwork.