Service sector industries and firms have been subject to relatively little research to date. Given the heterogeneity of services, the present study focussed on a small subset of the service sector, namely the knowledge intensive professional business service firms (PBSFs). The study was designed with a dual purpose: First, to identify and document key dimensions of PBSFs, and secondly to develop a grounded theoretical framework for the strategic management of globalizing PBSFs. The study was designed as an in-depth comparative case study, including five firms from three industries, based in the United States as well as Europe. Data were primarily collected through semi-structured interviews, but also include on-site observations as well as published and internal documents. In addition, a small subset of the propositions from the theoretical framework were operationalized and tested in a questionnaire survey at the SBU level within the five firms. The results of the study include four key areas: first, an extended discussion of the definition of the concepts "global" and "globalizing", "professional", "service", and "business service". Secondly, the tentative identification of core dimensions of PBSFs, and the resulting challenges for research and theory building as well as for management, including the emphasis on innovation rather than efficient replication of tasks, the interaction with the client in service definition, production, and delivery, the information asymmetry between service supplier and buyer, and the intangible nature of outputs. Thirdly, the study suggests the extention of the dynamic resource based perspective into a strategic management theory applicable to PBSFs, through an increased emphasis on competence assets controlled by individual professionals and only contracted by the firm. Finally, the study suggests improvements of previously tested questionnaire items for future survey studies of PBSFs. The surprising heterogeneity of PBSFs found is expected to result from differences between underlying professions, between industries (continuous versus ad hoc demand) and between firms' relative emphasis on assets and strategies for the future, domestic as well as global strategies.
