The Last Planner System is one of the most remarkable practices in lean construction and usually a starting point for lean implementation in construction companies. Different aspects of its application have been discussed along a number of articles since the first IGLC conferences. However, despite the many studies on this subject, the reasons for some recurrent patterns in the outcome data of the system and how they influence each other still remain to be explained. One of them is the cyclic nature of the PPC indicator that appears in most of the implementation examples presented in those articles. This article aims to help understanding such behaviour by developing a system dynamics model to investigate the influence of the variability, delays and project performance over the whole system. The model offers an explanation about how PPC fluctuations in the present may be explained by events in the past and, particularly, how to avoid undesirable outcomes in the future behaviour of the indicator.
System dynamics, Last Planner System