Time Impact Analysis (TIA) is a prospective delay analysis methodology that models the impact of a delay event by inserting it into the project schedule at the point in time it occurred and measuring the resulting shift in the completion date.
TIA is considered the gold standard for delay analysis because it examines each delay event in the context of the programme as it existed at the time, accounting for actual progress and any previous delays. It is recommended by the AACE, the SCL Protocol, and most major dispute resolution bodies.
The methodology involves: (1) establishing the baseline schedule, (2) updating to reflect actual progress up to the point of the delay event, (3) inserting activities representing the delay event and its logical relationships, (4) re-scheduling to determine the new completion date, and (5) comparing the two dates to quantify the delay.
TIA requires high-quality programme records — specifically, updated schedules at regular intervals showing actual progress. Where these are not available, a retrospective method such as windows analysis or collapsed as-built may be more appropriate.