Lean construction is increasingly popular as an object of academic research. Here practitioners and researchers immersed in lean construction present their views on worthwhile research topics and on the frontier of knowledge. It is meant to help any student interested in researching lean construction. Please, do not hesitate the contact the originator of each topic for further guidance.

At the moment, the following research topics are posted:

• Toyota's Set-Based Design
• Root cause analysis of plan failures
• Lean construction and safety
• Peculiarities of construction
• Rise and fall of production science

If you want to suggest an addition to this list of research topics, please contact the IGLC Webmaster.

The Toyota Production System is widely recognized as the prototype for lean production in manufacturing. It now appears that Toyota has also pioneered new and radically more effective product development processes as well. This poses the enjoyable task of determining the underlying principles of Toyota's "set-based concurrent engineering" and translating/adapting them for the construction industry. The result may well constitute Lean Design in parallel with Lean Production. A starting point for exploration of this vast research space is proposed; namely, to focus on techniques for avoiding needless repetition in the design process. As a starting point, the following are proposed:

• Posing alternative design solutions as sets, as opposed to point solutions.
• Deferred commitment in general, with or without explicit specification of sets defining the design space, the timing of which requires knowledge of the supplier lead times associated with the decision deferred.
• Design structure matrix for use when a specific design direction has been established or alternatives are being explored.
• Team problem solving (cross-functional teams) for use when iterative loops cannot be avoided.
• Design redundancy when task sequence cannot be structured to avoid iterative loops and team problem solving is not feasible.

Contact Glenn Ballard, ballard@ce.berkeley.edu

Rapid and continuous learning is recognized as they key to organizational success. The Last Planner system of production control advocates organizational learning for the purpose of improving system performance. However, there appears to have been little systematic application of this feature of the Last Planner system. Most improvements in plan reliability appear to have resulted from application of other Last Planner rules regarding the lookahead process and quality criteria for assignments, rather than from identification and action on root causes of failures to complete planned work. It is proposed to explore techniques of root cause analysis in other applications to determine if and how they can be applied to design and construction. There has also been developed a set of guidelines for reasons analysis that the author proposes for experiment and refinement. The guidelines have been developed around the elements of the Activity Definition Model which are:

• Directives
• Prerequisites
• Resources
• Processes

To get these guidelines and for further information, please contact Glenn Ballard, ballard@ce.berkeley.edu

Proponents of lean production claim that the introduction of lean production usually halves the accident rate. There are several mechanisms that could be playing a role here: there is less material in the working area, there are fewer disturbances and firefighting, the workplace is orderly and clean, etc. However, we do not presently have empirical evidence in construction on this hypothetical relationship. Furthermore, if there is a strong relationship, which features of lean construction especially are instrumental in promoting safety? On the other hand, companies like Dupont have aggressively progressed towards the zero accident target, independently of lean construction initiatives. Which safety principles they are using? Is there any overlap with lean construction safety principles? More on this topic from Lauri Koskela, lauri.koskela@vtt.fi

It is customary to view that there are certain peculiarities of construction, like one-of-a-kind products, temporary organization, and site production. It is often held that advances in construction are related to the elimination of these peculiarities, like site production by means of industrialization or one-of-a-kind products by means of pre-engineering. These peculiarities are also at the core of the argument that construction is so different, especially from manufacturing that technology transfer from other fields is not possible. However, even if it is easy to find short treatments of construction peculiarities in the literature, there is little accumulation in understanding in this respect. Moreover, related knowledge is qualitative; there have been few, if any attempts to acquire quantitative empirical data on the occurrence or impact of these peculiarities. To which extent are construction products one-of-a-kind? To which extent is the project organization temporary? Which share of the total construction production (the supply chain included) does occur on site? Next, what are the penalties for these peculiarities. For example, how much more costly is a one-of-a-kind product in comparison to pre-engineered product. On the other hand, which are the reasons for these peculiarities? Which are the penalties of pre-engineered products, in terms of lessened choice etc.? Obviously, we have few absolute truths here; nevertheless case studies regarding representative product types could be very illuminative. Finally, are there managerial strategies that could be used for alleviating problems caused by peculiarities? - This is a tough topic, but in need of clarification with regard to further progress of production management in construction. More on this topic from Lauri Koskela, lauri.koskela@vtt.fi

The long and haphazard formation of the production theory provides an invitation for research. Why did the efforts of industrial engineering in the 1920s to advance the flow view of production wither away? More on this topic from Lauri Koskela, lauri.koskela@vtt.fi