How to Perform Schedule Time Impact Analysis in Primavera P6?

A recent study reveals that schedule issues continue to be among the biggest construction claims issues in the USA, which further exacerbated the necessity to have an accurate analysis of the delays in construction projects. A schedule time impact analysis for Primavera P6 involves checking the approved baseline, adding the delay to the progress to the delay date, adding a delay fragment to the schedule, recalculating the schedule, and comparing the change in the completion date to the baseline.

When project teams don’t know this, they tend to make incorrect judgments about who is responsible for the delays. Preparation of schedule data, modelling of the delay and comparison of the results of the schedules. This framework outlines the workflow, delay classification and interpretation of results to enable a defensible analysis.

Before You Start | Time Impact Analysis Requirements in Primavera P6

There are a handful of checks that need to be performed prior to modeling a delay in Primavera P6. Check for agreement on the schedule and that it is based on an approved baseline. All comparisons are based on this.

Check next, the data date. It should reflect the most up to date progress report. outdated data can distort the results. Next, collect delay data. This involves sending letters, reporting on sites and notices relating to contracts.

Lastly, check the sequence of the schedule. Review activity relationships, constraints and activity status. This decreases the possibility of mistakes that may impact the analysis in the future.

Step-by-Step Guide to Perform Schedule Time Impact Analysis in Primavera P6

Establish the Schedule Foundation

Prior to any modelling of a delay, be sure that the project is based on an approved baseline schedule. Update all the actual start and end dates up to the delay date. Also be sure to check the data date, status, linkages and constraints.

Review Supporting Project Information

A good record is essential for doing an accurate analysis. Analysts also participate in coordinating the cost estimation, material calculation, volume analysis and project planning support processes, as well as review the project planning data through primavera p6 scheduling services to ensure consistency with the project’s documents.

Identify the Delay Event

Make sure that the delay is clearly defined. Record:

The affected activities
The range of dates (beginning and ending)
The root cause
Any events related to the contract(s)

For instance, design changes could be put through late in the design process, which could mean that structural work is delayed for several days. Measurable schedule effect is the only effect to be analysed.

Create and Insert the Delay Fragnet

A small network of activities that is the representation of the delay event is called fragnet. Please put fragnet in the updated schedule at the appropriate time. Follow these principles:

Assign Realistic Durations.
Make Activities to Represent the Delay. Produce Activities Symbolizing the Delay.
To Use the Right Connections Between the Predecessors and Successors.
Don’t Have to Make Any Logic Changes Elsewhere that Are Not Necessary.

Recalculate the Schedule

After inserting the fragnet run the schedule calculation. Make a comparison of the revised timetable.

Check:

Project completion date
Critical path sequence
Total float values
Newly critical activities

Measure the Time Impact

The impact modeled time is the difference between the two completion dates.

For example:

Due to fragnet, this date has been extended. The new fragnet date for completion is October 10.
The work will be complete after fragnet: October 17th.

Model Impact: 7 days.

Before holding someone responsible for the delay, however, be sure it is a real critical path delay.

How to Interpret Time Impact Analysis Results

Focus on Critical Path Changes

Only when critical and/or near-critical work is delayed does the delay extend the project. Check to see if the fragnet caused the critical path to change to other tasks.

Examine Float Consumption

Some activities use up the available float, but don’t affect the overall length of the project. If so, the project might not have as much flexibility in the schedule, but could not end up with more days to complete.

Compare Multiple Schedule Versions

Typically, a comprehensive review will consist of:

Approved Baseline Schedule
The Following Is the New Back-Up Schedule (prior to The Delay)

When using fragnet insertion, the resulting schedule might be impacted. The following comparison will aid in understanding the analysis to the owner, contractor and reviewers of disputes.

Classifying Delays for Accurate Analysis

Excusable Delays

Excusable delays occur when there is some event which is beyond the control of the contractor. Examples include:

Unusually severe weather
Owner-directed changes
Delayed site access
Regulatory actions

These events can be considered to help justify a time extension, if they impact the project’s completion.

Non-Excusable Delays

Non-excusable delays are caused by problems related to the contractor(s). Examples include:

Poor labor planning
Late procurement
Equipment shortages
Ineffective supervision

Usually the contractor will still be liable for these delays.

Concurrent Delays

Concurrent delays are delays to the project in the same time period that are independent of each other. There are two types of delays, one the owner’s and another the contractor’s.

Analysts should document:

Overlapping time periods
Affected critical activities
Responsibility for each event

Documentation helps to minimize claims disagreement.

Common Mistakes That Reduce the Accuracy of Time Impact Analysis

A Time Impact Analysis, even a minor schedule change, can impact the accuracy of the analysis. Common pitfalls are using the wrong baseline, having the wrong activity logic, having incomplete documentation, not considering concurrent delays and using the wrong data date. Make sure to check the schedule and supporting documents prior to conducting the analysis.

Preparing a Time Impact Analysis Report for EOT Claims

When the stakeholder(s) can read a clear report, they will have a better understanding of the impact that the delay had on the project’s schedule. Schedule Data and Project Records to be used to support every conclusion.

The following is typical of what is included in a report:

Project background
Describe the analysis and the purpose of it
Delay description
Analysis methodology
Schedule comparison
Results and findings
Supporting documents

Compare baseline, updated and impacted schedule using schedule snapshots. Making comparisons visually helps to make changes more easily understood. Keep assumptions transparent. When the analysis is based on a project record or contractual provisions, specify the nature of the project record and/or contractual provisions. This will help to ensure consistency and minimise misunderstandings when reviewing.

Time Impact Analysis vs. Other Delay Analysis Methods

There are a number of ways to assess construction delays; each is used for a different purpose. Time Impact Analysis looks at the impact of a particular delay by adding a fragnet to an up-to-date schedule. This is best suited in a project with an active status, and availability of reliable progress updates.

When you add a delay event to the original baseline schedule, it will be added to the schedule as Impacted As-Planned. Easy to execute, but it will not take into account the actual project progress, potentially decreasing the accuracy.

Schedule Performance is evaluated in Windows Analysis by analyzing performance of the schedule in different time periods. This approach is able to give an in-depth assessment of the past, and typically involves more past changes to the schedule. The best way to do it will depend on the documentation of the project, the requirement of the contract and the time of the delay event.

Primavera P6 Tools That Make Time Impact Analysis Easier

There are several capabilities built-in to Primavera P6 to enhance the quality and consistency of a Time Impact Analysis.

Baselines and Schedule Comparison

Baselines are the project plan baseline that serves as the baseline to compare the original project plan. Changes in activity dates, logic, float values and completion of the project due to a delay can be identified with schedule comparison.

Activity Codes, Filters, and Reflection Projects

Activity codes help to group together correlated activity and allow delayed activities to be readily identified. Filters restrict the data that is processed, enabling analysts to concentrate on the relevant data in the schedule. Reflection projects are used to test out schedule changes without changing the actual project schedule, in a safe environment.

Conclusion

Doing a delay on a schedule is not enough to get an accurate time impact analysis. The key to reliable results is to take a valid base line, ensure proper schedule logic, track delay events, and thoroughly assess CP changes.

A Time Impact Analysis is an objective assessment of delays and it is a structured method that can be used for project decision making. If each step is based on good scheduling principles, the analysis will be more reliable, transparent, and applicable to addressing schedule-related queries.

FAQs

Q1. Is it possible to do Time Impact Analysis after project completion?

Yes. Time Impact Analysis can be done at the time of an active project, but can also be done post-project if it is possible to get reliable updates on the project schedule, project documentation, and supporting documentation. The accuracy is dependent upon the quality of historical project data.

q2. Do all project delays need a Time Impact Analysis?

No. If the delay does not impact the critical path or project the project is not at risk of failing, it does not often warrant a formal Time Impact Analysis. The method is most useful if there is a time lapse that might affect the project completion date or contractual requirements.