In a separate article titled Schedule Critical Path, I have pointed to four different settings (criteria) commonly used to calculate path criticality. These configurations and associated filters were supposed to be general knowledge to all planning and scheduling specialist and experts. However, this is an assumption that fails more than too often.

The reality of the matter is, more than a few have used the wrong schedule calculation settings and filters from day one. Unless persuaded to change, they will do so indefinitely.

Again, as in previous article, we refer to the primary path when talking about critical path unless specifically described as another.

The first one we will discuss is the longest path, followed by Total float equal or less than zero. Third on the line is the Path with the lowest Total Float (it can be positive, zero or negative), and last but not the least, one defined by the contract (the client’s definition of criticality or the “it depends” critical path).

Together, let us review how the Longest Path (LP) compares to the calculation using Total Float (TF). These are the two main approaches. Both represent the critical path and fundamentally cover how we would deal with the third and the fourth criteria.


Criteria 1: Critical Path is the Longest Path

A scheduling default and most commonly used critical path definition uses the longest path on the Schedule Option dialogue box. The Primavera scheduling tool can identify critical activities without specifying any total float value by merely saying “Yes” to the longest path filter and following additional setting prescribed by the tool.

It will identify the primary critical path from the last activity of the open schedule up to the earliest and back. The longest path is the longest path in the open schedule network from start to finish.

It is the path with the longest overall duration. Its duration is the project overall remaining duration.

Note the word “remaining.” If the project has not started yet, then the longest path is from the first activity to the last activity. If the activity has already started, the longest path is from the first remaining driving activity to the last activity.

LP is the path through the schedule network where total duration is greater than any other path.


Many planners and schedulers using Primavera do not know that they must follow a certain specific setting to identify the primary critical path when using the longest path as criteria


Continue reading by following the hyperlink below:


Setting the Critical Path