Since the Last Planner System (LPS) was devised in the early Nineties, a number of studies have pointed out the need to understand the underlying theory in which it is based on. The Language-Action Perspective (LAP) has been suggested as a suitable approach to understand the management of commitments in the LPS. However, none of the previous studies have provided empirical evidence on the utility of LAP as a theoretical approach for explaining the LPS. This paper reports the results of a research project that aimed to investigate some benefit the utility of the LAP for evaluating the effectiveness of planning and control systems, emphasizing medium and short term planning. Two case studies were carried out in different construction companies, both of them highly experienced on the use of LPS. In each company, the production planning and control system of one project was assessed, based on the mapping of the network of commitments regarding the medium and short term planning levels. Besides, an in-depth analysis of planning meetings was made, describing how they were carried out, who effectively participated in decision-making, and how the commitments were managed. In both studies, it was possible to track down how the commitments were initiated, and in some cases to analyse the integrity of the workflow loops in the network of commitments, and the consequences of failures in those loops for the planning and control system.
Last Planner System, Language-Action Perspective, Network of Commitments, Production planning and control