Kanban, Feat. Hal Macomber

Reflections on CPM, Scrum, and Kanban

I recently had the chance to reflect deeply on how we use CPM, Scrum, and Kanban in construction and what they really mean for building strong project systems.

When I first encountered CPM (Critical Path Method), it was clear why it had become such a standard in our industry. It provides confidence, especially for owners and clients who want predictability. For many federal projects, you cannot even start without a CPM schedule. On the surface, it feels safe and structured. But over time, I realized that CPM does not actually help us design or operate a true project-based production system. It ignores flow and does not align with production laws like Little’s Law. Worse, it often functions as a solitary exercise, with one person behind a computer producing a schedule that others are expected to follow, leaving collaboration behind.

By contrast, when I was introduced to Scrum, I was struck by how much it encouraged teamwork and engagement. It came out of the Agile movement in software, where collaboration and reducing stress were central goals. In construction, Scrum helped project teams work in shorter cycles with clear priorities. However, it quickly became obvious that Scrum does not naturally focus on flow. You can bring production thinking into it, but it is not built in. And in construction, flow is critical.

This is where Kanban really stood out to me. Kanban, which also grew from Agile, was designed to keep work flowing. It brings production principles to the forefront by visualizing tasks, limiting work in progress, and encouraging continuous improvement. When I first saw Kanban boards in use on construction projects, I realized how powerful they could be for connecting office work with field needs. Whether it was procurement, RFIs, or logistics, Kanban created visibility and alignment. Unlike CPM, it is not about throwing a schedule at people. Unlike Scrum, it does not leave flow as an afterthought. Kanban blends people and flow together.

What strikes me most now is that construction is inherently socio-technical. We cannot succeed by focusing only on the technical side. The people, their communication, and their engagement are what bring systems like Takt or Kanban to life. CPM can feel easier because it avoids that complexity, but it does not address the real problem. The harder but better path is to embrace systems that require full participation and create flow for both people and production.

Key Takeaway:
CPM creates confidence but ignores production laws and collaboration. Scrum supports teamwork but overlooks flow. Kanban brings people and flow together, helping us build healthier and more resilient project systems.