The Power of “And”—Short-Interval Planning and Critical Path Method Scheduling

The team takes larger chunks, or sequences, of the work and uses a “pull” technique to determine hand offs.
Workflow of task planning in ourPlan.
Mid-way on a DPR project, the team raised the overall PPC rate to 86 percent. The reported industry average PPC is between 50 and 60 percent.

Used in conjunction with an appropriately detailed critical path method master schedule, milestone-based short-interval planning helps teams increase efficiency, deliver more predictable project results

While it doesn’t replace the strategic overview of the more traditional critical path method (CPM) schedule as a primary project control tool, short-interval planning (SIP)—when used in conjunction with CPM—has demonstrated the ability to help improve overall efficiency. The construction industry has seemingly been debating whether CPM or SIP is the right planning and scheduling tool. The answer is: both.
SIP shifts planning control from what may have been a single “planning guru” or small management group and relies on a more interactive, interdependent scheduling process comprising multiple project participants.

Incorporating lean scheduling tools, including “Last Planner® System and pull planning, SIP is a milestone-based approach, which focuses on “right-planning” exactly what is needed in the short term. This approach helps teams adapt more quickly to the often fluid, fluctuating demands of today’s construction projects. SIP concentrates on detailed, intensive and more frequent planning efforts surrounding key project milestones and engaging the cooperation of individuals who are executing the work in the field.


DPR project teams across the country, including superintendents such as Lance Wafler on the Facebook data center project in Forest City, NC, and Tom Corey on the Arizona State University (ASU) W. P. Carey School of Business project in Tempe, AZ, have experienced firsthand the benefits that SIP delivers in tandem with a strategic CPM schedule.

“I wouldn’t want to do [a project] any other way,” Corey said. “Once you commit to it, go through the learning curve, and use all the tools, it truly works.”

Communicating some part of the plan daily and in greater detail provides a major benefit to the project in addition to high-level scheduling, according to Wafler. Subcontractor input and commitment are essential.

“When you go into a pull-planning session and present a plan in a way that includes feedback to and from the subcontractor, you walk away with a better and more detailed plan, and the subcontractor has buy-in. Everybody is working towards the same agenda.”


The SIP process has three primary lean-based components, all of which work symbiotically to achieve the best result:

  • Pull-Planning Session: The team takes larger chunks, or sequences, of the work and uses a “pull” technique to determine hand offs. The team starts at the end of that portion of work and works backwards, identifying what is needed at each stage to start and complete each work segment.
  • Look-Ahead Meeting: During this weekly meeting, the subcontractors and general contractor work together to take the results from the pull-planning session (the larger two- to four-week framework of the project) and dial it down into smaller pieces.
  • The Daily Huddle: Finally, the third leg of the stool is a 10- to 15-minute start-of-the-day meeting when workers and field managers “huddle” to review activities planned on the jobsite at an hourly or daily level.

Using these components together provides a better opportunity to identify and proactively deal with issues that show the potential to slow things down.

“When you go through the steps, the process really uncovers inexperienced individuals or companies that don’t have the right tools to do the work. This is uncovered much more quickly than in traditional planning,” Wafler said. “It allows you to adjust your plan around the problem areas. That, in turn, gives you the opportunity to be more productive, providing a benefit and savings in the end.”

Plan percent complete (PPC) rates also are closely tracked, which Corey said is typically a major motivating factor. PPC is a basic measure of how well a planning system is working by calculating the number of assignments completed on the day stated divided by the total number of assignments made for the day.

“Measuring PPC really pulls the team together and makes us all better planners,” said Corey. “It brings accountability to the process. If a team member misses a date, they answer to the entire team.”

One key tool being used to optimize and facilitate SIP is a lean construction application known as “ourPlan” that supports the Last Planner System for optimizing SIP. More than 50 DPR projects are currently using ourPlan, ranging from large-scale hospital projects to small Special Services Group (SSG) projects nationwide.


Like anything that is new or unfamiliar, teams implementing SIP may run into roadblocks from navigating an initial learning curve to a fear of a loss of planning control to pushback about the additional meetings that are required.

Once the entire team, including subcontractors, understands and embraces the process, however, the benefits become clear.

“It really does work, if you just stay the course and implement the processes,” said Wafler. “Everyone gets better, and soon the team is really cohesive and understands how to interact to formulate a good plan.”

The ASU Business School project is one that clearly benefited. According to Corey, “We weren’t firefighting; everything was well planned out.”