TIA Sample Review: Why Time Impact Analyses Fail and How to Validate Them

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MLR Project Management & Consultancy | TIA | Delay Claims

Time Impact Analyses (TIAs) are widely used to justify time‑extension requests, but their credibility depends entirely on the accuracy of the underlying schedule and the discipline of the methodology. A recent delay‑claim review conducted by MLR Project Management & Consultancy illustrates how methodological missteps—particularly in schedule selection, logic handling, and validation against actual progress—can significantly distort the results of a TIA.

This article summarises the findings of that review, with all project‑specific details removed for confidentiality.

Executive Summary

A contractor submitted a TIA asserting that a change order requiring additional asbestos abatement caused a 69‑day delay. The review found that:

  • The contractor used the wrong unimpacted schedule (September 2025) instead of the last accepted schedule prior to the delay (August 2025), which carried +8 days of float.
  • The impacted schedule contained 18 unexplained logic changes among existing activities, unrelated to the fragnets.
  • After correcting the schedule selection and isolating the contractor’s added logic, the true variance was 39 days, not 69.
  • The contractor claimed mitigation but provided no supporting evidence.
  • Most importantly, actual project progress showed the project finishing ahead of the contract completion date, even after inserting the fragnets.

Because the project never exceeded the contractual finish date—and float remained available—the final outcome is a zero‑day delay. The time‑extension request is therefore not justified.

Delay Claims Review

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Understanding the Conctractor’s Claim

The contractor asserted that a change order requiring additional asbestos abatement disrupted the planned sequence of work and shifted the project completion date from 31 May 2028 to 8 August 2028, resulting in a 69‑day delay.

To support this claim, the contractor submitted:

  • A September 2025 schedule update as the “unimpacted” schedule
  • A fragnet modelling the added abatement work
  • An impacted schedule showing the resulting delay

However, the review found that the TIA was built on an incorrect foundation.

1. Incorrect Schedule Selection

AACE 52R‑06 requires using:

“The last Owner‑accepted schedule statused and updated prior to the time of the change or delay.”

The contractor identified the delay start as 10 September 2025, yet used the September 2025 schedule update—statused after the delay began.

The correct schedule should have been the August 2025 update, which:

  • Was the last accepted schedule before the delay
  • Carried a data date of 26 August 2025
  • Showed +8 days of total float
  • Forecasted an early completion of 23 May 2028

Using the wrong schedule eliminated float and inflated the apparent delay.

MLR Project Management & Consultancy | TIA | Delay Claims
Figure A. Comparison of two schedule updates showing differing projected completion dates.

2. Unexplained Logic Changes

The impacted schedule included:

  • 13 valid fragnet activities, and
  • 51 logic changes, of which
  • 18 were unrelated to the fragnets

These 18 changes were made between existing activities, not the added fragnet tasks. The submission did not explain these modifications.

When the fragnets were neutralised (zero duration), the schedule still finished 30 days later than the contractor’s unimpacted version—showing that the contractor’s own logic changes contributed to the delay.

MLR Project Management & Consultancy | TIA | Delay Claims
Figure B. Impact of contractor‑added logic changes on the unimpacted completion date.
MLR Project Management & Consultancy | TIA | Delay Claims
Figure C. Fragnet activities representing the modelled change order impact.

3. The Correct Delay Was Not 69 Days — It Was 39 Days, and Ultimately 0 Days

Once the correct schedule update was used—the August 2025 schedule update—the analysis changed significantly.

After isolating the contractor’s additional logic changes and recalculating the unimpacted completion date based on the proper schedule version, the true unimpacted finish date was:

  • 30 June 2028, not 31 May 2028

Using this corrected unimpacted date reduces the variance against the impacted completion date of 8 August 2028 from 69 days to 39 days.

However, when the TIA results were validated against actual project progress, the remaining 39‑day variance disappeared entirely. The latest schedule update available at the time of the TIA (January 2026) showed the project finishing 12 days ahead of the contract completion date, and even after inserting the fragnets, the forecast completion shifted only from 19 May 2028 to 26 May 2028—still earlier than the contractual finish.

Because the project never exceeded the contract completion date, and float remained available, the final outcome is a zero‑day delay.

4. Mitigation Not Demonstrated

AACE 52R‑06 requires contractors to mitigate delays “to the extent practicable.” The contractor referenced resequencing as mitigation but provided no evidence, such as:

  • Before‑and‑after dates
  • Revised work plans
  • Documented mitigation actions

Given the duration of the alleged delay, the absence of mitigation documentation is a significant deficiency.

5. Actual Progress Invalidated the Claimed Delay

The January 2026 schedule update showed:

When the fragnets were added, the forecast completion shifted only from 19 May 2028 to 26 May 2028—still earlier than the contractual finish.

Contract requirements state that a time extension is only granted when:

  • All float is consumed, and
  • The projected finish extends beyond the contract completion date

This threshold was not met.

This validation step confirms the final outcome of zero delay.

MLR Project Management & Consultancy | TIA | Delay Claims
Figure D. Latest schedule update showing forecast completion ahead of the contract date.

6. Final Determination

The time‑extension request is not justified because:

  • The wrong unimpacted schedule was used
  • Unexplained logic changes distorted the results
  • Mitigation was not demonstrated
  • Actual progress contradicted the claimed delay
  • The impacted completion date did not exceed the contract completion date

The final outcome is zero days of delay.

MLR Project Management & Consultancy | TIA | Delay Claims
Figure E. Latest schedule update with fragnets applied, showing no extension beyond the contract completion date.

What This Means for Owners and Contractors

For Owners

  • Verify the schedule used in a TIA is statused before the delay
  • Scrutinize logic changes—these often reveal manipulation
  • Compare TIA results with actual progress
  • Require documented mitigation efforts

For Contractors

  • Follow AACE 52R‑06 rigorously
  • Avoid modifying logic unrelated to the fragnet
  • Document mitigation actions clearly
  • Ensure the TIA aligns with real‑world progress

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