Sven Diethelm

Assessing the impacts of implementing lean construction

Over the last 10 years an increasing number of companies have implemented lean construction practices in an attempt to improve performance in construction projects. Most companies, and also some researchers, have reported satisfactory results from their implementation. However, there is still a need to provide more extensive analysis of the empirical evidence available to assess the impact of the implementation of lean construction. The authors have researched the implementation of the Last Planner System and other Lean Construction techniques in over one hundred construction projects over the last five years. They have also developed strategies and support tools for implementation. This paper analyses some of the main impacts observed in the studied projects, and some of the lessons learned from implementations. The paper discusses difficulties and barriers for implementation, productivity improvements, variability reduction and effectiveness of implementation strategies. The paper also provides recommendations for future implementation and research.

Strategies for improving safety performance in construction firms

Over the years many prevention management practices have been implemented to prevent and mitigate accidents at the construction site. However, there is little evidence of the effectiveness of individual or combined practices used by companies to manage occupational health and safety issues. The authors selected a sample of 1180 construction firms and 221 individual practices applied in these companies to analyze their effectiveness reducing injury rates over a period of four years in Chile. Different methods were used to study this massive database including: visual analyses of graphical information, statistical analyses and classification techniques. Results showed that practices related to safety incentives and rewards are the most effective from the accident rate viewpoint, even though they are seldom used by companies; on the other hand, practices related to accidents and incidents investigation had a slight negative impact on the accident rate because they are frequently used as a reactive measure. In general, the higher the percentage of prevention practices implemented in a strategy, the lower the accident rate. However, the analysis of the combined effect of prevention practices indicated that the choice of the right combination of practices was more important than just the number of practices implemented.