The Lean Methodology of Project Scheduling
Lean scheduling is a way to combat delays and “firefighting” with careful, collaborative planning that ultimately increases efficiency and reduces waste. Delays and “firefighting” may seem like a typical part of the construction process – but it doesn’t have to be that way.
A key difference between Lean scheduling and traditional scheduling is the planning process used. In traditional scheduling, typically one person – like the project manager and/or superintendent – dictates the direction of the project based on past experiences. Lean scheduling, on the other hand, allows early input from subcontractors who have a better (and more realistic) understanding of the time, resources, and manpower requirements needed to complete their portion of the project.
Todd Miller, a Superintendent at Rafn, was one of several Rafn employees who attended a Lean scheduling seminar in Texas last year. “At the seminar we attended we did several scheduling exercises for a mock project. For each exercise the room was divided by all the different trades for the given project. And the exercises were timed.”
A key idea of Lean Scheduling is the creation of a pull plan, which is a way of working backwards from a target milestone date, breaking up and defining the tasks to outline what everyone needs to get to that goal. “We all provided schedule input working through the process in the traditional method, i.e. working from start to finish, using our durations for the scope of work based on experience. We then performed the same exercise working from finish to start using the pull planning method,” says Miller.
By including subcontractors in planning the master schedule, subcontractors become a more integral part of the team and will be more likely to meet the goals discussed. They take ownership in the process, and thus feel more obligated to making sure milestones are met on time.
“Each trade established the resources they needed to complete their scope and it was all posted on the board using sticky notes. Trades could then be coordinated to stack and efficiently move from one scope to the other. In the end, it took about half the time to perform the same scope as the traditional method. Working from finish to start allowed “weigh-in” from each trade, making for a much faster and efficient experience. It creates reliability in scheduling so everyone is making promises they can actually keep,” he says.
Pull plans help determine who can work in what area without impacting others and helps define workflows so that subcontractors can effectively hand off work areas to the next in line. This reduces lead times and the waste of waiting. It helps reinforce just-in-time deliveries which keep job sites from getting cluttered and creates a safer working environment.
“In Seattle especially, storage is such a constraint, it pays for stuff to show up when it’s close to being used so that it isn’t sitting for weeks.”
While Lean scheduling can work for entire projects, Miller notes that it can also be used in smaller pieces of the whole.
“Lean tools like daily check-ins and huddles can make a big difference,” he says. Communication is key to a successful project, and knowing what work is being done each day and the challenges the crew may be facing further creates a collaborative, team environment.
Lean scheduling uses a Six-Week Look Ahead (SWLA), which is distributed on a weekly basis so that each subcontractor and team member can forecast work, confirm material delivery schedule, and identify any possible problems that might keep their portion of the work from starting. To support the SWLA, a Weekly Work Plan (WWP) is given to subcontractors to complete, detailing all the tasks that are needed to accomplish the activities described in the SWLA. Clear communication and defined handoff points ensures that work is never waiting on workers and workers are never waiting on work.
By having better planning and continuous communication, it’s much easier to prevent “fires” from happening in the first place. The SWLA helps find potential problems well in advance, while daily huddles and WWP identify constraints as they come up.
Under the Lean approach, the ultimate goal is to remove constraints before they impact the start date of a defined activity. Everyone shares a responsibility in identifying potential problems, and by establishing a collaborative work environment through the lean methodology, team members will be able to document and track constraints effectively.
One way of documenting constraints is by listing them out on a whiteboard in a high-traffic, highly visible area. This allows any team member to add the constraint as they become aware of them and makes them easy to review. Every constraint should be listed in addition to the activity affected if the constraint isn’t removed, the champion of the constraint or the team member responsible for getting it taken care of, and the impact date of when work will be affected if the constraint isn’t resolved.
With detailed planning and open communication, constraints can be identified and workflow maintained. Efficiency, productivity, and profits will ultimately increase and, hopefully, reduce stress for those involved. While Lean scheduling does demand consistency and involvement, it also emphasizes collaboration and mutual respect. Input is always welcome, and when everyone buys into the same plan, teams will have better outcomes in every phase of project delivery.