Introduction :

1. Impact as Planned (IAP)

• Definition: This method evaluates the impact of a delay event by inserting it into the baseline (as-planned) schedule and analyzing the changes.
• Approach: The original schedule remains unchanged. The impact of the event is assessed without considering actual progress or dynamic updates. Delays are simply added as if they occurred exactly as planned.
• Limitations: Does not account for project progress at the time of delay. May not be an accurate representation of the actual impact if the project has already deviated from the baseline.

Example: If a contractor submits an RFI (Request for Information) that takes 10 days to resolve, you insert a 10-day delay into the as-planned schedule to see how it affects milestones.

2. Time Impact Analysis (TIA)

• Definition: A forward-looking delay analysis method that evaluates the impact of a delay on the schedule based on the project’s current progress at the time of the delay.
• Approach: The delay event is inserted into a copy of the most current schedule update (not just the baseline). The schedule is recalculated (forward and backward passes) to determine how the completion date is affected. Typically used in forensic delay analysis and extension of time (EOT) claims.
• Advantages: Provides a realistic assessment of how delays affect future activities. More accepted in dispute resolution and legal claims because it considers actual project conditions.
• Example: If the project is already delayed due to procurement issues and a new weather delay occurs, TIA evaluates the compounded effect of both delays instead of just adding the new delay to the baseline.

Key Differences

Which One to Use?

• Use IAP when performing an early assessment of potential delays before they occur.
• Use TIA when evaluating the actual impact of a delay for contractual claims, change orders, or forensic schedule analysis.

Would you like guidance on performing a Time Impact Analysis in Primavera P6?