Why Method Selection Matters More Than Most Attorneys Realize
In construction delay litigation, the scheduling expert's report is only as strong as the analytical method behind it. Courts and arbitrators evaluate not just the conclusion — "Owner X caused Y days of delay" — but whether the methodology used to reach that conclusion is recognized, systematic, and appropriately applied to the available documentation.
Choose the wrong method for the evidence you have, and opposing counsel can attack the entire analysis on cross-examination. Choose the right method and build it correctly, and delay causation becomes a matter of fact — not opinion.
The Four Recognized Forensic Schedule Methods
1. Time Impact Analysis (TIA / Fragnet Method)
Time Impact Analysis is a prospective, event-driven method. The analyst creates a "fragnet" — a small sub-network of activities representing the delay event — and inserts it into the contemporaneous schedule at the time the delay occurred. The before-and-after comparison shows the event's impact on the projected completion date at that point in the project.
Best for: Projects with a well-maintained, regularly updated P6 baseline and a clear, discrete delay event with a defined start and end date. TIA is the preferred method when the contract specifies it, and it is the most frequently used method in U.S. construction arbitration.
Documentation required: A complete, contemporaneous schedule update for the period immediately preceding the delay event. Change orders, RFIs, and daily reports establishing when the delay began and ended.
Cross-examination vulnerability: TIA is event-specific — it quantifies one delay at a time. Complex projects with multiple overlapping delays require multiple TIA analyses, and opposing counsel will challenge whether each fragnet correctly captures the delay's logic and duration.
2. Windows Analysis (Time Slice Analysis)
Windows analysis divides the project into time "windows" — typically based on monthly update periods — and evaluates delay causation within each window independently. For each window, the analyst identifies the critical path, determines what events caused delay to that path, and assigns responsibility.
Best for: Projects with multiple, overlapping delay events from different parties — common in transit, hospital, and large infrastructure programs. Windows analysis handles concurrent delay more rigorously than TIA because it evaluates causation within discrete time periods rather than treating the project as a single event sequence.
Documentation required: All schedule updates from baseline through project completion, plus contemporaneous records (daily reports, change orders, correspondence) for each time window. Missing updates significantly weaken a windows analysis.
Cross-examination vulnerability: Window boundary selection is a judgment call that opposing counsel will challenge. If the windows are drawn to maximize one party's apparent delay, the analysis will not survive cross.
3. As-Planned vs. As-Built
The as-planned vs. as-built method compares the original baseline schedule to a reconstructed as-built schedule — showing how actual activity completion dates deviated from planned dates and drawing inferences about delay causation from those deviations.
Best for: Cases where the project lacks sufficient contemporaneous schedule updates to support TIA or windows analysis. It is also useful for a quick preliminary assessment of delay magnitude before a full forensic engagement.
Cross-examination vulnerability: This method has significant weaknesses. It does not account for concurrent delay, it treats the entire project as a single comparison rather than analyzing causation period by period, and it can produce misleading results when the original baseline was unrealistic. Many arbitrators view this method with skepticism in complex claims.
4. Impacted As-Planned
The impacted as-planned method starts with the original baseline schedule and inserts delay fragnets representing the claimed events, showing what the projected completion would have been if the baseline had remained intact but the delays had occurred.
Best for: Situations where the project was abandoned, terminated, or where no schedule updates exist after the delay events occurred. It is rarely the first choice when contemporaneous updates are available.
Cross-examination vulnerability: This method is prospective — it models what would have happened, not what did happen. When contemporaneous records are available, opposing counsel will almost always argue that this method is inferior to TIA or windows analysis.
What to Ask Your Scheduling Expert Before Retaining
Before retaining a scheduling expert for a delay claim, ask three questions: First, what schedule updates and contemporaneous records are available for the project period in question? Second, does the contract specify a required method for delay quantification? Third, what is the nature of the delay — a single discrete event or a series of overlapping events from multiple parties?
The answers to these three questions should drive method selection. An expert who recommends a method before reviewing the available documentation is working backwards — and that approach rarely survives the scrutiny of a serious arbitration.
If you are evaluating whether a delay claim is worth pursuing, or preparing a defense position for an incoming claim, CPM Pros's TIA and delay claim support service includes a preliminary document review and methodology recommendation before the full engagement begins.