The Hidden Pitfalls of CPM: How It Increases Work in Progress
The Critical Path Method (CPM) is widely used in construction scheduling, but it comes with a serious downside—it increases work in progress (WIP) beyond the available capacity of resources. This creates unnecessary stress, inefficiencies, and delays that can derail a project. Let’s break down why this happens and what you should do instead.
Understanding CPM and Its Impact:
CPM schedules projects using a time-on-top, deliverable format, where activities are logic-tied in sequence. A computer algorithm then performs forward and backward passes to determine the critical path—the sequence of tasks where any delay impacts the entire project.
The problem? This method forces work to start as early as possible without considering resource availability, pushing teams beyond their limits and creating chaos on-site.
Why CPM Increases Work in Progress:
Here’s how CPM inflates work beyond a manageable level:
- No Buffers in the Critical Path – With zero float, delays are inevitable, yet there’s no flexibility built into the schedule.
- Early Start Mentality – Everything is set to start as soon as possible, overwhelming trade partners.
- Large Batch Areas – Work is scheduled in massive chunks rather than properly zoned sequences.
- Trade Stacking – Too many trades are forced to work in the same area at the same time.
- Trade Burdening – Individual trades are scheduled in multiple areas simultaneously, making it impossible to maintain efficiency.
The Downward Productivity Spiral:
When CPM inflates work in progress:
- Productivity drops as teams struggle with overcrowding and mismanaged sequencing.
- Projects finish late because crews are constantly behind.
- Costs increase due to wasted effort and rework.
- Worker morale declines, leading to more mistakes and inefficiencies.
A Better Approach:
Instead of CPM, flow-based scheduling with proper zoning, realistic work sequencing, and built-in buffers can help projects stay on track without overloading resources.
If you want to learn more we have:
-Takt Virtual Training: (Click here)
-Check out our Youtube channel for more info: (Click here)
-Listen to the Elevate Construction podcast: (Click here)
-Check out our training programs and certifications: (Click here)
-The Takt Book: (Click here)
Discover Jason’s Expertise:
Meet Jason Schroeder, the driving force behind Elevate Construction IST. As the company’s owner and principal consultant, he’s dedicated to taking construction to new heights. With a wealth of industry experience, he’s crafted the Field Engineer Boot Camp and Superintendent Boot Camp – intensive training programs engineered to cultivate top-tier leaders capable of steering their teams towards success. Jason’s vision? To expand his training initiatives across the nation, empowering construction firms to soar to unprecedented levels of excellence.
On we go