Logic Driven vs Resources Driven Logic

In scheduling, not all dependencies are the same. We distinguish between:

Logic Driven: These are the classic activity relationships—block work → plaster → paint → ceiling → tiles. Each floor follows its own logical sequence.

Resource Driven: This is where reality challenges the software. For example, plastering across multiple floors may overlap, and Primavera might show manpower spikes—10 masons, then 20, then 30, then 10 again —numbers that are impractical in real life.

The solution? Introduce resource-driven links between floors or locations.

To avoid unrealistic peaks and valleys in the resource histogram, align activities so crews finish one floor before moving to the next. This creates realistic allocations and avoids the “planning vs. reality” gap.

Other Concepts Explained:

• Drivers: When multiple predecessors exist, the driver determines which activity truly controls the start date.
• Free Float: The time an activity can be delayed without impacting its successor. For example, plaster may finish 5 days earlier than paint begins - those 5 days are free float.

By combining logic-driven and resource-driven dependencies, you build schedules that are not only technically correct but also practical, efficient, and execution ready.