Delay Analysis Challenges in Primavera P6

Primavera P6 is a widely used project management software that offers comprehensive features for project planning, scheduling, and control. However, when it comes to delay analysis, Primavera P6 presents unique challenges. This article explores Delay Analysis Challenges in Primavera P6, focusing on constraints, multiple calendars, actual date manipulation, out-of-sequence activities, dangling activities, and negative float. It provides valuable insights for professionals involved in analyzing delay claims using Primavera P6. It is important to note that while Primavera P6 excels in project time and cost management, its primary focus is not specifically tailored towards measuring and assigning responsibility for delays and accelerations. The following sections will explore the various challenges that P6 users may encounter when using Primavera for assessing claims and conducting delay analysis.

Challenges of Delay Analysis in Primavera P6

• Working with Constraints in P6

The accurate use of constraints is essential in delay analysis to avoid unforeseen outcomes. It is imperative for analysts to thoroughly assess constraints for their feasibility. It is important to distinguish contractual constraints, which are directly tied to contractual obligations, from other constraints. Analysts should be aware of whether constraints are contractually mandated or implemented solely to influence the analysis results. While it is a common practice to utilize constraints to consume float and designate specific activities as critical, it is crucial to approach this practice with care. Neglecting to properly consider constraints can introduce significant risks to the integrity and precision of delay analysis.

• Working with Multiple Calendars in P6

In the latest versions of Primavera, the ability to assign different calendars to each activity enables the creation of more realistic schedules. However, it is important to note that utilizing different calendars can sometimes result in inaccurate delay analysis outcomes. This inaccuracy arises from the fact that Primavera P6 does not explicitly define the responsibilities of non-working days specified in the calendars. Often, these periods are contractually classified as Excusable Non-compensable delays, for which neither the owner nor the contractor should be held accountable. Consequently, the decoupling of responsibilities from the calendar allows for potential manipulation within Primavera P6.

In addition, Primavera P6 includes functionality that schedules activities based on their late dates instead of early dates, resulting in all activities being identified as critical. However, it is crucial to avoid using this option as it leads to highly inaccurate delay analysis. Manipulating a schedule to designate noncritical activities as critical during the identification of delay events is commonly referred to as “Spring-Loaded.”

To identify such manipulations, we in Leopard recommend four checkpoints methodology:

• Are activity durations consistently multiples of 5-day or 7-day weeks? This suggests a lack of effort in accurately estimating activity durations.
• Does the percentage of critical activities to noncritical activities exceed 10%?
• Are constraints deliberately manipulated to force noncritical activities into the critical path?
• Is the average float per activity unusually high compared to typical scenarios?

• Actual Date Manipulation in P6

When updating a Primavera P6 schedule, it is crucial to convert both the early and late dates to actual dates for accurate documentation of as-built data. However, incorrect assignment of actual start or finish dates can lead to unexpected delay analysis results. It is worth noting that manipulating the schedule by altering actual dates is a recognized tactic employed by contractors in delay claims. To mitigate such issues, it is advisable to exclude all actual data when analyzing delay claims. Additionally, incorporating delay types within Primavera P6 alongside actual data can be a valuable solution. Unfortunately, current versions of Primavera P6 do not provide identification of delay and acceleration types (such as Excusable/Compensable delay and Owner/Contractor’s Acceleration) for each activity’s duration. Consequently, P6 users who neglect to consider delay and acceleration types in activity durations, as well as disregard non-working periods specified in the calendar, may face challenges in accurately analyzing delay claims.

• Out of Sequence Activities

The term “Out of Sequence” refers to activities that are originally planned to start in a specific sequence but are instead initiated simultaneously with overlap to expedite the project. Consequently, the successor activity commences “out of sequence.” The current versions of Primavera address this situation by implementing one of two methodologies: “Retained logic” or “Progress override.” These approaches handle schedule updates differently. “Retained logic” maintains the original sequence logic, enabling the out-of-sequence activity to start early while still adhering to the predetermined sequence for completion. In this case, the activity cannot reach completion until all its predecessors have finished. On the other hand, “Progress override” treats the out-of-sequence activity as if it has no predecessors, allowing it to continue without being affected by its unfinished predecessors.

• Dangling Activities in P6

A “dangling” activity is an activity that is not tied to any successor activities (open-end activities). Primavera marks the status of these activities as critical because they are independent of the rest of the activities on the schedule.

However, it is essential to note that assuming a delay on a dangling activity will directly result in a project delay is not a realistic approach. The determination of total float for dangling activities is a challenging task, making it advisable to associate them with the project start and finish dates. This association enables the calculation of total float for dangling activities. Sometimes, an activity linked to both a start and finish date can unexpectedly become a “dangling” activity, often without the scheduler’s awareness. Such situations arise when Start-to-Start and Finish-to-Finish relationships are utilized. These dangling activities have adverse implications for delay analysis since they are disconnected from their float path, and their criticalities are challenging to ascertain. To mitigate these issues, we at Leopard recommend utilizing the Finish-to-Start relationship to avoid such problems.

• Negative Float in P6

Within P6 scheduling, the concept of float typically represents a value of zero or a positive number. However, in recent times, negative float values have emerged to signify not only critical activities but also their ability to cause a negative delay on the total float, thereby postponing the project. The presence of negative float in delay analysis prompts Primavera P6 to interpret it as an indication of criticality. Nevertheless, there are instances where negative float may inadequately identify critical activities. To determine the critical path, two approaches are commonly employed. The first approach relies on the total float value, considering it to be zero or negative. The second approach focuses on identifying the longest path. In situations involving concurrent delay or a transition from a critical to noncritical path, these two approaches yield disparate results.

CONCLUSION

The article identifies six areas of concern which the user should be aware of. Some solutions are suggested to avoid inaccuracy while using Primavera P6 scheduling software in its analysis. Therefore, the ideal scheduling approach through the P6 should address the following:

• Track the schedule progress time and cost.
• Fix the project delay/acceleration responsibilities.
• Track the total float responsibilities.
• Determine the damages in time and cost for all project participants.

At Leopard Project Controls, we specialize in offering comprehensive delay analysis services. Our analysis includes a meticulous examination of all relevant driving factors in your project, ensuring that we consider every aspect of the project’s impact, changes, and delays. We meticulously incorporate these factors into the schedule to accurately evaluate the actual project impact.