TIA vs. As-Built Analysis: Choosing the Right Delay Methodology

When a delay claim reaches the review stage — whether by an owner, a claims consultant, or legal counsel — the first question is almost always about methodology. How was the delay quantified? What analysis technique was used? Is it the right one for this situation?

The choice of forensic delay methodology is not a technicality. It determines whether your analysis is accepted as credible or dismissed before anyone reads past the executive summary.

The Main Forensic Methodologies

Time Impact Analysis (TIA)

TIA is a prospective or retrospective analysis that inserts a specific delay event into the accepted baseline schedule at the point in time when the event occurred, and measures the resulting push to the completion date. It is the most widely accepted methodology by public agencies — USACE, Caltrans, Port Authority, and most state DOTs specify TIA in their scheduling specifications.

TIA works best when there is a well-developed baseline schedule with honest logic and float, and when the delay events are discrete and documentable. It loses credibility when the baseline schedule was poorly constructed or when float was artificially constrained from the start.

Windows Analysis

Windows analysis divides the project into time periods and analyzes the critical path within each window separately. It is the most rigorous methodology for complex projects with multiple concurrent delays from both parties, because it can isolate which delays were owner-caused, which were contractor-caused, and whether they were concurrent.

It requires a complete set of schedule updates and contemporaneous project records. It is time-consuming but produces the most defensible result on complicated claims.

Collapsed As-Built

The collapsed as-built methodology starts with the actual as-built schedule and removes the owner-caused delay events to show what the completion date would have been without those delays. The difference between the actual completion and the collapsed completion represents the compensable delay.

It is often used when the project is complete and a good baseline was never established, because it works backward from what actually happened. It is more vulnerable to challenge than TIA because it relies heavily on assumptions about what would have occurred absent the delay.

How to Choose

The right methodology depends on three factors: the quality of the schedule record, the nature of the delay events, and what the owner or agency will accept. If your contract specifies TIA, use TIA. If you have a complete set of updates and multiple concurrent delay events, windows analysis is the more defensible choice. If the project is complete and the schedule record is thin, collapsed as-built may be your only option — but document your assumptions carefully.

The worst outcome is choosing a methodology because it produces the largest number, rather than because it is the most appropriate for the available project record. An experienced claims reviewer will identify that immediately.

A Fourth Method Worth Knowing: Impacted As-Planned

Impacted as-planned analysis starts from the original as-planned baseline — not a contemporaneous update, and not the as-built record — and inserts delay events directly into that original logic to measure their theoretical effect on completion. It is the least data-intensive of the four AACE-recognized methodologies, since it requires only the original baseline and a list of delay events rather than a full set of periodic updates. That simplicity is also its principal weakness: because it ignores how the schedule was actually being executed and updated as the project progressed, it is the methodology most vulnerable to challenge when a complete update history exists and the other side can show the baseline itself did not reflect how work was truly sequenced. Impacted as-planned is generally reserved for situations where TIA and windows analysis are not feasible — commonly when the contemporaneous update history is incomplete or missing — because a defensible baseline is available but the periodic record needed for the more rigorous methods is not.

Why Methodology Choice Gets Challenged in Practice

Opposing analyses in a delay dispute rarely disagree only about the facts — they frequently disagree about which methodology was even appropriate to apply, and that disagreement is often where the real fight happens. A claims reviewer or opposing expert will typically ask three questions before evaluating the substance of any analysis: was the chosen methodology consistent with what the contract's scheduling specification requires, was it consistent with the quality and completeness of the available schedule record, and was it applied consistently rather than switched mid-analysis whenever a different method would have produced a more favorable result. An analysis that fails any of these three threshold questions can be discounted before its substantive conclusions are even considered, regardless of how carefully the underlying calculations were performed. Selecting the right methodology at the outset, and documenting why it was selected, is therefore not a technical formality — it is often the difference between an analysis that gets engaged with on the merits and one that gets dismissed on a threshold objection.

Whichever method applies, the underlying requirement is the same across all four: a schedule record thorough enough to support the analysis honestly. Methodology selection can optimize what is possible with the record you have, but it cannot substitute for a record that was never created. That is the argument, ultimately, for building schedules defensibly from the baseline forward rather than relying on forensic technique to reconstruct a case after the fact.

In practice, most experienced forensic schedulers do not commit to a single methodology before reviewing what records actually exist. The right first step on any delay claim is an honest inventory of the schedule record — how many updates exist, how complete the logic is in each, whether cost and resource loading was maintained, and what contemporaneous narratives accompany each period — because that inventory determines which methodologies are even available before any question of which one is preferable gets asked. Skipping this step and defaulting to whichever methodology a template or a prior project used is how avoidable, entirely preventable challenges to an otherwise sound and well-supported delay claim end up happening in practice.