A general contractor on a public park and outdoor recreation complex in the Greater Toronto Area had reached substantial-completion pressure with the schedule visibly drifting against the owner’s contractual milestones. Mid-project, the owner had issued a unilateral schedule update with retroactive baseline edits applied to activities and logic in earlier data dates — movements that conflicted with the contemporaneous correspondence record the contractor held in its own files.
The contractor needed an independent forensic of the as-planned-vs-as-built record before any EOT submission left its desk. The question was simple but load-bearing: which days are owner-caused, which days are contractor-caused, and what does the schedule chain itself say about how the answer changed over the eight updates the owner pushed through?
Critical Path Partners performed a contemporaneous windows analysis across the full owner’s update chain, paired with a chain-diff forensic on the XER files themselves — testing whether the schedules opposing counsel would later cite as the contemporaneous record were, in fact, contemporaneous. The methodology stack was AACE Recommended Practice 29R-03 MIP 3.3 for the windows analysis, Eichleay for the home-office overhead allocation tied to the entitlement days, and SCL Delay & Disruption Protocol §3 (notice review) and §11.5 (extension of time) for the procedural and entitlement spine.
The chain-diff forensic on the owner’s eight XER updates surfaced the load-bearing finding: retroactive TASKPRED edits and baseline-date movements in the owner’s update chain that were inconsistent with the contemporaneous correspondence record. The owner’s later schedule updates had quietly edited activities and logic in time periods that pre-dated their own data dates — movements that, if accepted at face value, would have shifted the entitlement footprint away from the owner column. The contemporaneous RFI and change-directive thread the contractor held did not support those edits.
Most forensic schedule reviews look only at activity-finish slippage between two snapshots. The chain-diff approach reads the schedule chain as a sequence and tests whether each later update is consistent with the data it pre-dates — the test that separates a genuine contemporaneous record from a record that has been groomed downstream.
CPP delivered a windows-analysis dashboard, a slip register with per-window party-attribution, the Eichleay home-office overhead computation, the SCL §3 notice review, and the evidence ledger linking each RFI and change directive to the specific chain-diff manipulation in the owner’s update sequence. The deliverable supplied the contractor and its counsel with the substantiation needed to file the EOT submission, including the rebuttal record against the owner’s retroactive edits.
Outcome: Substantiated EOT entitlement; matter resolved. The methodology disclosure, the AACE-aligned attribution, and the chain-diff evidence held through the owner’s review process. Specific entitlement-day counts and resolution figures are not disclosed; the engagement is confidential.
If the schedule chain you’re being asked to accept doesn’t match the correspondence record you actually have, that is exactly the work this engine was built for. Fixed-fee preliminary assessment in two weeks. No hourly burn.
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