A longitudinal quantitative research on the impact of collective staff performance management on team cohesion does not show any significant effect. Implementation of team objectives and performance assessment at team level in a medico-social organization does not seem to improve team cohesion. The lack of observed effects is explained by organizational practices which are not in line with collective values, by the lack of support from managers, team instability/turnover, and the absence of collective rewards. The research shows that the collective staff performance management processes does not lead to positive effects when the context is not supportive, in particular when managers are not able to bring the collective principle to life through constant dialogue.