Time Impact vs. As-Planned vs. As-Built: Choosing the Right Methodology

Not all delay analysis methodologies carry the same weight. When to use each method, what arbitrators expect, and how to structure an analysis that stands up under scrutiny.

Delay analysis is not a single technique. It is a family of methodologies, each with different strengths, different weaknesses, and different levels of acceptance across jurisdictions and dispute forums.

The As-Planned vs. As-Built method is the simplest. It compares the planned programme with what actually happened and attributes the difference to identified delay events. It is easy to understand, relatively quick to prepare, and often sufficient for straightforward delay situations. Its weakness is that it is retrospective and does not account for the dynamic nature of construction programmes.

The Time Impact Analysis (TIA) is more sophisticated. It inserts each delay event into the programme at the point it occurred and measures its impact prospectively. This methodology is generally preferred by arbitrators because it reflects the reality of how delays affect a live programme. Its weakness is that it requires a robust and properly updated baseline programme — which many contractors do not maintain.

The As-Built Collapsed method works backwards from the actual completion date, removing delay events one by one to determine what the completion date would have been without each delay. It is useful when the baseline programme is unreliable or unavailable, but it is more complex and can be contentious.

The choice of methodology is not arbitrary. It depends on the quality of the programme records, the nature of the delays, the contractual requirements, and the expectations of the dispute forum. Using the wrong methodology — or applying the right one poorly — can undermine an otherwise valid delay claim.

CALIM's delay analysis practitioners select and apply the methodology that best fits the facts, the contract, and the forum. The goal is always the same: an analysis that is robust, defensible, and credible.