Introduction
Forensic delay analysis seeks to determine what delayed a project, when the delay occurred, how it affected the programme and, where relevant, which party bears responsibility. The reliability of the conclusion depends heavily on the quality of project records and programme logic.
Time Impact Analysis (TIA)
TIA generally models a delay event as an impact on the contemporaneous programme update. It can be particularly useful where reliable update programmes exist and the analyst can isolate the effect of individual events within the relevant time windows.
Windows Analysis
Windows Analysis divides the project duration into defined periods and evaluates changes in critical path, progress and delay causes between those periods. It can provide a detailed chronology of how the critical path evolved, especially on long and dynamic projects.
As-Planned vs As-Built
This approach compares the planned programme against actual performance. It is comparatively straightforward conceptually, but conclusions can become unreliable if the baseline is poor, the as-built record is incomplete or the analysis does not adequately account for changes in logic and critical path over time.
How to select the method
Methodology should follow the evidence, not the desired result. Consider the quality of the baseline, number and quality of updates, availability of contemporaneous records, project complexity, changes to logic and the purpose of the analysis.
What makes an analysis defensible?
A defensible report explains the methodology, assumptions, data sources, programme integrity, critical-path logic and limitations. It should allow another competent analyst to understand how the conclusion was reached and to reproduce or challenge the analysis.
Conclusion
There is no universally superior delay-analysis methodology. The strongest forensic opinion is normally the one that is proportionate to the dispute, supported by the available evidence and transparently applied.