In GPM (and CPM), the critical path is the longest continuous path to the project completion (or an interim contractual milestone), when anticipating on-time or early completion. If anticipating late completion, the critical path is any continuous path that extends beyond the contract date for a completion milestone.
For example, if a project were already significantly behind schedule, a large number of activities might already be critical. To reduce the noise and identify only the most critical, the threshold could be changed to -5 instead of 0. Conversely, if a project were ahead of schedule, there might not be any critical activities. In this case, the threshold could be set to positive 5 so that even activities with total float were signaled out. By default, critical activities and hammocks are automatically turned red, but they may be outlined instead to preserve their original color.
When using outlines, actualized activities will only have their nodes outlined in red to preserve the blue outline on the bar. In-progess activities will have their progressed portion outlined in blue and their remaining portion outlined in red. Actualized milestones and benchmarks will not be outlined in red, despite the setting.
NOTE: A hammock will display as critical if at least 1 member is critical.