Planning, Scheduling, and Control of Construction Projects Tom Stephenson , published by American Technical Publishers
Before the era of AI-driven project management and BIM (Building Information Modeling), Stephenson recognized a fundamental truth: Unlike manufacturing, where variables are controlled, construction sites face weather, labor fluctuations, material delays, and design changes.
In Stephenson’s model, an activity must have defined boundaries. A common mistake he highlights is creating activities that are either too broad (unmanageable) or too granular (impossible to track). The sweet spot is activities lasting between 4 hours and 10 days.