MANAGEMENT OF PRODUCTION IN CONSTRUCTION: A THEORETICAL VIEW Lauri Koskela1 ABSTRACT The transformation view and the flow view are two major conceptualizations of production. The current practice in construction is based on the transformation view. However, the transformation view is an idealization, and in a complex production situation the associated idealization error may become large. This is exactly what happens in practice. Task management, based on the transformation view, assumes that certainty prevails in production. However, it is widely observed that, due to the inherent variability of production in construction, intended task management degenerates into mutual adjustment by teams on site. It is argued that the transformation view and the flow view should be synthesized into a new theoretical view on construction. The inherent causes of variability in construction can be explained and the countermeasures for eliminating variability or stemming its impact can be pinpointed by this new theoretical view. It is shown that the Last Planner method is compatible with this new view. KEY WORDS Production theory, construction, project management, Last Planner.
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INTRODUCTION Would we be better off if we had an explicit theory of construction? This question may seem trivial at first glance, however, in the framework of construction management as a discipline, there has been little emphasis on theory development. To clarify the question posed this paper endeavors to answer to two more specific questions: Which theoretical foundations exist for production? How should construction and methods used in it be interpreted from the point of view of a theory of production? Due to space limitations, the discussion is highly selective. Construction design is not treated, even if design is almost always a part of construction production, construction being one-of-a-kind production. Production on site is emphasized, rather than production in the framework of the supply chain. From various production principles, the focus is on the variability reduction principle. The paper is structured as follows: First, it is clarified why we need a theory of production and what it is. Next, two basic conceptualizations, transformation and flow, are reviewed, and the need for a synthesis is noted. After this, flows and transformations in construction production are analyzed. Finally, based on this analysis, design, control and improvement of production in construction is considered. THEORY OF PRODUCTION WHY DO WE NEED A THEORY OF PRODUCTION? An explicit theory of production will serve various functions. A theory provides an explanation of observed behavior, and contributes thus to understanding. A theory provides a prediction of future behavior. On the basis of the theory, tools for analyzing, designing and controlling can be built. A theory, when shared, provides a common language or framework, through which the co-operation of people in collective undertakings, like project, firm, etc., is facilitated and enabled. A theory gives direction in pinpointing the sources of further progress. A theory can be seen as a condensed piece of knowledge: it empowers novices to do the things that formerly only experts could do. It is thus instrumental in learning. When explicit, it is possible to constantly test the theory in view of its validity. Innovative practices can be transferred to other settings by first abstracting a theory from that practice and then applying it in target conditions. From the point of view of practice of production management, the significance of the theory is crucial: the application of the theory should lead to improved performance. In reverse, the...