A FOUNDATI ON OF PROJECT MANAGEMENT THEORY Louis Lousberg 1 and Hans Wamelink Department of Real Estate & Housing Delft University of Technology, Delft, The Netherlands ABSTRACT The product approach of project management theory still outweighs the social science approach. The latter deals with power and politics, as constituent as it is in managing projects. Choosing the linguistic turn as a starting point of the paradigm change that has been made in organizational studies, in this paper, the foundations, the theorizing and examples of the social science approach will be explored. This exploration is based on a literature study and the preliminary results of PhD research on conflicts in complex Public Private Partnership projects in spatial developments. First, the ontological and epistemological starting point of this approach is elaborated by a description of an attempt of Husserl to escape the subject/object dualism. Next, the following theses are worked out: (1) there is not one theory, but there are multiple approaches; (2) there is not one form of managing projects, but there are several; and (3) due to the gap of knowledge of social project management forms research should be focused on the specific, context-dependent practice and be grounded in what practioners say about this practice. Based on these theses the paper ends with a conclusion about a foundation of a project management theory. 1. I NTRODUCTI ON Literature shows that “the underlying theory of project management is obsolete” (Koskela, 2002a), that “in prior literature it has been generally seen that there is no explicit theory of project management” (Koskela et al, 2002a) and that “several prominent authors have raised the need to introduce alternative theoretical approaches to the study of projects, and to identify the implications that they may have for how we organise and manage projects” (Cicmil et al, 2006b). Therefore, the quest for a theory of project management can be stipulated as problematic. Hence, the central question addressed in this article is: what is the foundation of a project management theory that is practical; practical in the sense that it enhances understanding for practioners and practical in the sense that it works? 2. STARTI NG POI NT: THE LI NGUI STI C TURN. In search for theories that are underlying the PMBOK, (Project Management Body Of Knowledge) as described in the PMBOK Guide of the Project Management Institute, it can be concluded that anomalies that occur in the application of these underlying project management theories are regarded as “strong enough for the claim that a 1 l.lousberg@bk.tudelft.nl 1