Every delay claim starts with a story about who caused what and when. Almost every dispute that follows comes down to whether that story can be proven with records that were created at the time, not reconstructed afterward to fit a conclusion. Courts and arbitrators do not resolve construction disputes by picking the more persuasive narrative. They resolve them by examining whether the schedule data and project documentation actually support the claim being made.
That distinction, between a plausible account of events and a documented one, is where most delay claims are won or lost long before anyone sets foot in a courtroom. A contractor or owner who waits until a dispute has already started to assemble a case is, in most instances, working from a significant disadvantage that no amount of skilled advocacy can fully overcome.
A Recent Case Shows What Actually Persuades a Court
A December 2024 case commentary from law firm Clark Wilson LLP on Walsh Construction v. Toronto Transit Commission, a 2024 Ontario Superior Court of Justice decision, offers a detailed look at how a court actually evaluates competing delay claims. The dispute involved a Toronto transit station project that finished more than three years behind its original schedule, with the contractor claiming 193 million dollars across 23 heads of damages.
The court’s reasoning is instructive precisely because of how it treated the two sides’ expert evidence. The contractor’s delay expert divided the project into 48 discrete time windows and analyzed the transition between each one using the contemporaneous schedule updates and an impacted schedule, concluding the contractor was entitled to 1,047 days of compensable delay. The owner’s expert, by contrast, offered only a critique of that methodology rather than an independent analysis of its own. According to the case commentary, the court found this distinction decisive: an expert opinion built on a genuine window-by-window schedule analysis carried real evidentiary weight, while a critique with no independent assessment behind it left the court effectively choosing between two numbers rather than evaluating the underlying facts. The court ultimately awarded the full 1,047 days the contractor’s analysis supported.
Windows Analysis and Contemporaneous Records
What made the contractor’s position persuasive was not the number itself. It was that the analysis was built from schedule updates that existed contemporaneously, meaning they were created and saved as the project actually progressed, rather than reconstructed from memory or backfilled from a final as-built schedule once the dispute was already underway. The case commentary specifically notes that the court’s confidence in the analysis rested on the fact that a genuine window-by-window comparison had been performed, tracing how the schedule’s critical path shifted across each reporting period.
This is the pattern that shows up across delay disputes generally: an analysis is only as strong as the schedule data behind it, and schedule data is only useful if it was captured and preserved as the project unfolded. A schedule reconstructed after the fact to support a legal position, no matter how carefully built, does not carry the same weight as a chain of contemporaneous updates that already existed before anyone anticipated a dispute.
A January 2025 report from the U.S. Department of Transportation’s Project Delivery Center of Excellence, examining the causes of construction change orders on federally funded transportation projects, reached a related conclusion from a different angle. The report found that agencies with documented, consistent processes for identifying, evaluating, and approving changes saw measurably fewer disputes and cost overruns than agencies relying on ad hoc, undocumented decisions made in the moment. The same documentation discipline that reduces change order disputes before they escalate is what later determines whether a delay claim can actually be substantiated if a dispute does arise.
A documented construction delay analysis that traces how the critical path actually moved across reporting periods, built from schedule data captured as the project progressed rather than assembled after a dispute has already started, is what separates the kind of window-by-window analysis that persuaded the court in the Walsh case from a critique that has nothing independent to offer in its place. The distinction is not about which side hires the better expert. It is about which side already has the underlying schedule discipline in place before the dispute ever begins.
Labor Shortages Are Producing More of These Disputes
An August 2025 workforce survey from the Associated General Contractors of America, conducted with NCCER, found that 78 percent of firms reported experiencing at least one delayed project over the prior twelve months, with worker shortages cited as the single most common reason. Ninety-two percent of firms hiring reported difficulty finding qualified workers, and 45 percent said labor shortages had directly caused delays on at least one project.
That volume of delay activity across the industry translates into a corresponding volume of disputes over who bears responsibility for the lost time, since a labor shortage affecting one contractor’s crews often intersects with owner-side scheduling assumptions, subcontractor sequencing, and other parties’ claims about what should have been anticipated. The more frequently delays occur across the industry, the more often the question of whose schedule discipline holds up under scrutiny actually gets tested.
A labor-driven delay is rarely a single clean event with one obvious cause. It typically ripples across trades and sequences in ways that are difficult to reconstruct months or years later without a contemporaneous record showing exactly when crews fell behind, which activities were affected, and how the critical path responded as the shortage played out. That is precisely the kind of detail a court weighing competing claims will look for.
What a Defensible Position Actually Requires
Based on how these disputes are actually decided, a few practices consistently separate a claim that survives scrutiny from one that does not:
- Schedule updates saved and dated as the project progresses, not reconstructed later from a single final version.
- A window-by-window or time-slice comparison that traces how the critical path actually moved across reporting periods, rather than a single before-and-after comparison.
- Independent analysis rather than critique. As the Walsh decision illustrates, a report that only challenges the other side’s methodology, without offering its own reasoned assessment, tends to carry far less weight with a court.
- Consistency between the schedule record and other contemporaneous documentation, including daily logs, meeting minutes, and correspondence, so that the narrative in the delay analysis is corroborated rather than standing alone.
- A clear, contemporaneous record of when delay events were identified and communicated, rather than an assessment assembled well after the fact.
The Discipline Has to Exist Before the Dispute Does
None of this can be built retroactively with any real credibility. The contractor in the Walsh case prevailed in large part because genuine, contemporaneous schedule data existed to support a rigorous window-by-window analysis. A project that has not been maintaining that kind of schedule discipline throughout construction cannot manufacture it once a dispute has already begun.
For owners and GCs alike, the practical lesson is not about who wins any individual case. It is about recognizing that the schedule updates being filed away every month, seemingly routine and unremarkable at the time, are the actual evidentiary record a court or arbitrator will eventually rely on if a dispute arises. Treating those updates as a compliance formality rather than a genuine record of what happened and when is what leaves a party with only a critique to offer instead of an independent, defensible position of its own.
The projects that come out ahead in these disputes are rarely the ones with the most aggressive legal strategy. They are the ones where someone was paying close enough attention throughout construction that, when the dispute eventually arrived, the record already existed to answer the question rather than needing to be built from scratch under pressure.
