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Time impact analysis (TIA)

A forward-looking method for modeling an event, inserting it into an appropriate contemporaneous schedule, and comparing the calculated effect.

Working definition

A time impact analysis models the potential schedule effect of an event: build a network fragment representing the event, insert it into an appropriate contemporaneous schedule, recalculate, and compare the relevant milestone before and after. AACE 52R-06 describes prospective TIA as guidance—not a universal standard—and separates modeled time impact from later cost and entitlement determinations.

Key takeaways

  • Select the statused schedule that the contract and method make appropriate—often the accepted update immediately preceding the event—and document why it represents the available information.
  • A prospective TIA is intended to use information available near the event so the parties can evaluate forecast effect while work continues.
  • Review the source schedule, information date, acceptance status, and calculation settings; trace fragnet durations and logic to evidence; reproduce the before-and-after calculation; test parallel paths, float, mitigation, and sensitivity; and reconcile the modeled days to the requested milestone.
01

The mechanics, step by step

Select the statused schedule that the contract and method make appropriate—often the accepted update immediately preceding the event—and document why it represents the available information. Preserve an unimpacted copy, add supported event activities, durations, calendars, and logic, hold unrelated calculation variables constant, and recalculate the specified milestone. Report the modeled difference, the float treatment, and any local disruption separately.

02

Why the method is respected — and its limits

A prospective TIA is intended to use information available near the event so the parties can evaluate forecast effect while work continues. Its credibility is inherited from the source schedule and the fragnet. Missing logic, unexplained settings, unsupported durations, or hindsight can make a precise calculation unreliable; those limitations should be corrected or explicitly qualified.

03

What a reviewer interrogates

Review the source schedule, information date, acceptance status, and calculation settings; trace fragnet durations and logic to evidence; reproduce the before-and-after calculation; test parallel paths, float, mitigation, and sensitivity; and reconcile the modeled days to the requested milestone. Then state what the model supports and which contract, responsibility, cost, or legal questions remain outside the technical result.

Sources and scope

Follow the reference trail.

This guide is original educational commentary. Kairos reference records identify the source organizations, editions and scope behind this guidance. The original publishers retain their publications and rights.

Recommended Practice 52R-06: Prospective Time Impact AnalysisAACE International · checked 2026-08-01Delay and Disruption Protocol, second editionSociety of Construction Law · checked 2026-08-01UFGS 01 32 01.00 10: Project ScheduleWhole Building Design Guide / U.S. Department of Defense · checked 2026-08-01