I still remember my first “aha” moment sitting in Glenn Ballard’s Lean Construction course. As both a PM and Superintendent on the Big Dig, I had struggled to figure out why some actions improved project performance and others made no dent in the chaos. That “aha” moment was my understanding how a lack of reliability impacts any process, and it brought perspective to all my prior successes and failures. All of a sudden, to get better results on any project, I had a lever I could focus on moving. And in fact, there are more. As a consultant, I have seen many teams both struggle and be hugely successful with the Last Planner System. The difference? Whether they grasp those levers and work to move them.
For teams that have struggled, they describe LPS as extra work, a way to get trades to ‘feel’ they are part of the plan, a means of getting more communication (by which they mean information), and a means to get collaboration. Thus, LPS falls by the wayside when there is not pressing need for more information or trades aren’t participating in planning or there is not time to do the extra work. Sound familiar? Though these teams may acknowledge that things seem to be a little less chaotic when engaging in LPS practices, they see less chaos as the cause for time to engage in LPS.
Struggling teams are often method and tool focused. If the LPS methods and tools presented do not produce significantly better results and are challenging to implement, then why change. However, if a team understands the cause and effect relationships in their processes, then they can see when a new method and tool failed to move the levers any more then their prior practices. For them, the question is not why change, but what to change instead to move the levers.
Teams that thrived have approached LPS from a perspective of problem-solving and continuous improvement of their project management methods based on three process laws and pull methods of control. These teams ask themselves how they can help move the levers of the process laws and what information, tools, routines and actions they would need. They then develop and test those tools and actions, refining or replacing them as they monitor how well the levers move. For successful teams they are redefining and replacing prior practices that failed to move the levers and keeping those that did.
Four levers that impact project success are the law of variation, law of batches, law of bottlenecks and pull method of process control. Everything in the design of LPS is designed to help move these levers. By understanding what these levers are and how LPS helps move them you can help your team establish the tools and activities that will help them unlock the full power of LPS.
Lever 1: The Law of Variation
When steps in a process are not reliable, i.e., do not go according to plan, it leads to workers waiting for work, or work waiting for workers, impacting both schedule and cost on a project. For example, if framing finishes an area early and the electrician is not yet ready, the framing waits and if framing is late, the electrician waits. Though you may find other use for that waiting time, back-up work, it will not be as efficient as what you planned. Imagine if framing and electrical rough for each area were reliable within half a day. How much less would everyone wait? How much savings could all parties gain?
Lever 2: The Law of Batches (Little’s Law)
If steps in a process release smaller amounts of work more frequently, instead of larger amounts less frequently, later steps start and end sooner, thereby reducing the overall schedule. For example, if four trades handed off half a floor in three days instead of a whole floor in six days, then the second trade would start three days sooner, the third six days sooner and the fourth nine days sooner.
Lever 3: Law of Bottlenecks
The pace of a process is limited by its slowest step. Everyone working at the same speed reduces workers waiting for work and work waiting for workers. It also means that efforts to advance schedule should focus on the bottlenecks. For example, if the electrician takes twice as long as the rest of the MEPs for in-wall rough as well as drywall and finishes, only increasing the electrician will have a direct impact on project completion.
Lever 4: Pull as a Control Method
Pull says to only produce work at the pace or request of the downstream operation. For example, if the electrician is behind in rough-in and requests less framing for the upcoming week, the framer only produces what the electrician needs.
By understanding how the four levers are related to the different components of the Last Planner System, you can gain a more fundamental understanding of how the LPS works. For example, in the figure below we have an illustration of how the daily huddles and the weekly work plan (two essential parts of the LPS) can be broken down into these levers.
Click here to download the webinar recording and learn about the principles behind the LPS. In the webinar, I go into greater depth about these levers and some real-world examples and results from this process.