Analyzing and comparing Professional Service Firms over services, time and space. Proposition of a foundation framework

International audienceResearch on professional service firms (PSFs) has been quickly developing over the last twenty years, especially emphasizing both PSFs' distinctiveness and their current challenges. Recent efforts by PSFs scholars have focused on the issue of understanding differences between PSfs regarding ongoing tensions (eg. tension between Partnership and Corporation) or to organizational differentiation over geographical boundaries and professional activities. Although these contributions shed light on different factors of heterogeneity between PSFs, there is still a lack of an integrated and actionable framework which would help analyzing PSFs changes, heterogeneity and distinctiveness over services, time and space. We propose a foundation framework which interconnects two dimensions, namely " governance " (composed of two sub-dimensions " objects " and " means ") and " operations " (composed of " resources " and " coordination "). This framework provides with dimensions to analyze changes in and differentiation between PSFs. It is then completed by the interactions with different dimensions of the environment which may explain changes and differentiation inside and between PSFs, namely regulation, clients, competitors and the socio-technical environment. Such a framework offers several contributions by representing comprehensively the organizational dimensions of a PSF and their coherence, by relating issues which are often considered separately and by arguing that organizational patterns are not simply deterministic but also depend on professionals' initiatives