By Mark McKenzie on Dec 13, 2017 1:08:40 PM
The term pull planning is being used more and more in construction planning and scheduling. Where did the term originate from? What does it mean exactly? What does pull planning replace? What are the benefits?
The Lean Construction Institute (LCI) and its founders Glen Ballard and Greg Howell certainly deserve the credit for their work in suggesting that the concepts of the Pull System or Just in Time (JIT) used so successfully in manufacturing could be applied to construction projects to improve scheduling reliability.
Although there are some conflicting accounts of the origin of the pull system, Toyota’s Taiichi Ohno is considered to be the “Father of JIT” (Just-In-Time). Implementing the Kanban pull system was a result of Toyota’s fascination with American supermarket’s. Inventory management, in general, and the observation of when a customer pulls an item from the shelf a signal was sent to replenish the item, were key lessons learned. Toyota’s implementation of the supermarket system began with in 1952 and was fully implemented by 1962. Nicole Radziwill in her article The Origins of Just-In-Time sums up the transformation when she says, “This (the supermarket system) was the genesis of the Toyota Production System (and sometimes elusive) socio-technical system for production and operations. This approach bridged the gaps between production and continuous improvement and became the basis for lean manufacturing as it is known today.”
I love this video of Greg Howell (LCI co-founder) describing his experiences and research that led to the founding of LCI and the development of Last Planner™ System: https://youtu.be/uRAoMG2RcDA. The goal of the Last Planner system is as Greg states, “Predictable work flow and rapid learning.” This is accomplished by utilizing a milestone master schedule, a short interval scheduling process designed to remove all constraints, and capturing reasons why, when plans are not achieved.
The LCI in their terms glossary provides the following definitions of “Pull” and “Push”.
“Pull” – A method of advancing work when the next in line customer is ready to use it. A “Request” from the customer signals that the work is needed and is “pulled” from the performer. Pull releases work when the system is ready to use it.
“Push” – “Push” – an “Order” from a central authority based on a schedule; advancing work based on central schedule. Releasing materials, information, or directives possibly according to a plan but irrespective of whether or not the downstream process is ready to process them.
I am just being lazy when I don’t cite studies, but for most of us that have been involved in larger complex projects, the idea that a scheduling technician can create a Master Schedule down to the Work Package level before the project starts and that’s how the project will actually be executed, is not plausible. This would be an example of the “Push” method of scheduling.
We tend to talk about projects that didn’t go well. Projects with poor productivity, cost overruns, schedule slippages, disputes, etc. I have been fortunate to be involved, more times than not, in numerous very large, complex industrial projects, with demanding owners that were completed with great safety records, ahead of time, with very happy customers. As an added bonus, we made or exceeded our bid margins.
The common thread with all of these projects was a commitment to detailed planning. TIC The Industrial Company implemented short interval scheduling in the early 1980s. It was piece of paper where the frontline supervisor (with help from superintendents) would list the tasks they planned to do the next week and the manpower required. In the comment section, they would list their needs (material, equipment, tools, area releases, etc.) The project manager, superintendents, and planners would review these schedules and needs, resolve conflicts, provide redirection if needed, and do everything possible to make sure the crews had what they needed, before the work began. It worked pretty well.
We didn’t know anything about The Toyota Production System, JIT, Kanban pull planning or any of these manufacturing processes. What we did know was short interval planning with collaboration and follow up, was critical to have any chance of staying on schedule and managing our labor costs. Come to think of it, I am not sure we new what collaboration meant back then. We worked together to solve problems.
I don’t mention the above to disparage the work LCI has done or CII with Advanced Work Packaging becoming a Best Practice ( https://www.construction-institute.org/blog/2015/advanced-work-packaging-becomes-cii-best-practice ). What they have done is to create standards, with research to back it up.
Trestles’ mission is to leverage our experience and the research that these great institutions have completed. Our goal is to provide frontline supervisor training and short interval scheduling technology that can be quickly and inexpensively implemented. Standards are great, but when it comes to your company, it is not a standard until everyone is using it.
 J.P. Womack, D.T. Jones, and D. Ross, The Machine that Changed the World, Rawson Associates, New York, 1990
 Nicole Radziwill, The Origins of Just-In-Time, https://qualityandinnovation.com/2010/10/13/the-origins-of-just-in-time/