Critical Path Management

Without clear insight into a critical path, management cannot determine which slipped activities will be detrimental to key program milestones and the program’s finish date. The more complex schedules will require additional analysis by tracing critical resources. Float within the schedule can be used to mitigate critical activities by reallocating resources from activities that can safely slip to activities that must be completed on time. Until the schedule can produce a valid critical path and a valid longest path, management will not be able to provide reliable timeline estimates or identify problems or changes or their effects. Moreover, management will not be able to reliably plan and schedule the detailed work activities.

As stated earlier, the critical path and longest path must be reevaluated after each status update because the sequence of activities that make up the paths changes as activities are delayed, finish early, occur out of planned sequence, or the like. Additionally, activity duration updates and changes to logic may alter the paths. After each status update, the critical path and the longest path should be compared to the previous period’s paths, and responsible resources should be alerted if previously noncritical and nondriving activities are now critical or driving. Likewise, resources that had been assigned to previously critical activities may now need to be reassigned to other critical activities. The critical and longest paths should make intuitive sense to subject matter experts. That is, the sequence, logic, and duration of critical activities should appear to be rational and consistent with the reviewers’ experience.

Depending on the overall duration of the program, management may benefit by monitoring near-critical activities as well. For example, in addition to monitoring critical path activities, management may wish to monitor activities with 5 days or less total float. Monitoring near-critical activities alerts management of potential critical activities and facilitates proper resource allocation before activities become critical.26

Conducting a schedule risk analysis (Best Practice 8) may reveal that, with risks considered, the path most likely to delay the program is not the critical path or the longest path in the static CPM schedule. The risk analysis may identify a different path or paths that are “risk critical.” Risk mitigation should focus on those risk-critical paths for best effect.

  1. Unfortunately, no easy method of calculating the “near longest path” in complex schedules would alert management and schedulers to activities near the path of longest duration.↩︎