Authored by: Rimkus Forensics Marketing Team
According to the American Arbitration Association, construction arbitration resolves substantially faster than litigation: for awarded cases closed in 2025, large-dollar construction awards were delivered on average about 1.7 times faster than the median time to trial in U.S. District Courts.
When an overrun becomes a claim, the parties need a defensible way to quantify how a specific event moved the completion date. Most forensic delay analysis work addresses that question.
Time impact analysis (TIA) is one commonly used method for answering that question, not the sole or universally preferred one. It models a delay event within a critical path method (CPM) schedule and measures how far the calculated completion date shifts.
AACE International’s RP 52R-06 is the U.S. recommended practice devoted specifically to prospective TIA, while its RP 29R-03 places the method within a broader forensic schedule-analysis taxonomy; the internationally recognized SCL Delay and Disruption Protocol also addresses it. These references treat TIA as a forward-looking tool, and post-completion use draws added scrutiny.
Key takeaways on time impact analysis
TIA depends on the analysis date and on whether the schedule update and project records support the modeled event. The sections below explain how those schedule updates, records, and standards affect the analysis.
What a TIA measures
- A TIA models a delay event in a CPM schedule and measures how far the completion date shifts
- TIA models schedule movement only; resource loading, productivity, and cost impacts generally require separate analysis
What makes an analysis defensible
- AACE RP 52R-06 is the U.S. recommended practice specific to prospective TIA, while RP 29R-03 provides the broader forensic schedule-analysis taxonomy; the internationally recognized SCL Protocol discusses it too
- Regularly updated contemporaneous schedules often give an analysis its strongest evidentiary weight
- Documentation gaps may foreclose certain methods
To discuss a schedule delay matter with the Rimkus team, contact us.
What is a time impact analysis?
Time impact analysis is a forward-looking schedule analysis technique that adds a modeled delay event to an unimpacted CPM schedule to measure potential movement in project completion. AACE International Recommended Practice (RP) 29R-03 and its companion RP 52R-06 address the method. RP 52R-06 defines TIA as “a forward-looking, prospective schedule analysis technique that adds a modeled event or events to an unimpacted schedule to determine the potential impact of that event(s) to the longest path and therefore project completion.”
The analyst builds a small network of activities representing a discrete delay event, inserts it into a CPM schedule, and recalculates. A CPM schedule is a logic-linked activity network whose calculations identify the critical path: the longest path through the network, which sets the shortest possible completion time. Activities on the critical path typically carry little or no total float, or negative float where an imposed deadline precedes the calculated finish, so delay to those activities can push completion.
AACE RP 29R-03 sorts methods into observational methods, which examine schedules unaltered, and modeled methods, which insert or extract delay activities. TIA is a modeled, additive method that inserts each delay event into the schedule update current at the time, while the impacted as-planned method instead adds delays to a single unprogressed baseline.
When TIA is used
AACE RP 29R-03 cautions that contractually specified methods “may be inappropriate for retrospective use,” citing prospective TIA as the example. The internationally recognized SCL Protocol takes a similar position, stating that where the parties or tribunal assess an extension of time (EOT) application after completion, prospective delay analysis “may no longer be appropriate.”
A TIA forecasts an impact from information available at the time. In disputes that reach a hearing well after completion, the parties by then know the actual outcome, and in that common but not universal scenario, parties can corroborate TIA results against as-built methods.
How does a time impact analysis work?
The analysis validates the schedule, models the event, recalculates the critical path, and measures the resulting date movement.
Establishing the baseline and inserting the fragnet
The analysis starts from the most recent schedule update before the delay event. AACE RP 29R-03 requires a properly set data date, an unbroken critical path, complete activity logic, and documented calendars; the SCL Protocol similarly requires the program be brought fully up to date “to the point immediately before the occurrence of the Employer Risk Event.” The analyst then locks an unimpacted copy recording the completion date, critical path, and float values.
A fragnet, or fragmentary network, is the sub-network modeling the delay event. The SCL Protocol defines it as “the instruction for the variation, the activities required to carry out that variation and its linkage to the activities in the Updated Programme.” The analyst builds it in the same software as the base schedule, ties it to actual dependency rather than imposed dates, and documents durations and assumptions. Successive events each go into the schedule already impacted by the prior ones.
Recalculating the critical path
The analyst reruns the CPM calculation and compares the impacted completion date to the unimpacted one. Under the SCL Protocol, a fragnet that only consumes float yields no predicted EOT: “An EOT should only be granted to the extent that the Employer Delay is predicted to reduce to below zero the total float on the critical path affected by the Employer Delay to Completion.” This is the Protocol’s position, not a universal rule; float ownership, risk allocation, notice compliance, and concurrency vary by contract and jurisdiction.
What standards provide guidance on time impact analysis?
Analysts evaluate TIA against the contract first, then test the method against scheduling standards and evidentiary rules; the choice between methods is ultimately a matter of judgment, not just formula.
RP 29R-03 supplies a taxonomy many U.S. practitioners cite. The document is deliberately non-prescriptive, stating it “is not intended to establish a standard of practice, nor is it intended to be a prescriptive document applied without exception,” so a departure grounded in sound scheduling principles is not automatically an error. Its companion, RP 52R-06, warns that “The longer the period between the event and the approval of the TIA, the less useful and valid the prospective TIA becomes.”
The current 2nd edition of the internationally recognized SCL Protocol (February 2017) discourages a “wait and see” approach to EOT assessment and identifies TIA as “recommended for a contemporaneous analysis of delay.” This changed the SCL’s earlier position: the 2002 1st edition had preferred TIA for both prospective and retrospective analysis, while the current edition recognizes six methods and states there is “no longer a preferred delay analysis methodology” for time-distant assessment.
Tribunals examine the schedule foundation behind a TIA label. In CTA I, the Civilian Board of Contract Appeals stated there “is, to be sure, a heavy presumption that regularly updated, contemporaneous schedules are the best evidence of project progress,” while also recognizing that a rigorous as-built approach reconstructing schedules from contemporaneous evidence can itself be an acceptable methodology.
What types of delay does TIA typically address?
TIA quantifies time movement; the contract and governing law determine whether that movement is excusable, compensable, both, or neither. AACE RP 29R-03 sorts delays into compensable, time-only, and non-compensable categories, each requiring the delay to affect the critical path. Weather and strikes typically excuse time without cost; owner-side events are more often compensable.
Concurrent delay complicates this picture. AACE RP 29R-03 flags it as a factor in method selection, since a TIA models only inserted events and may miss a concurrent contractor delay on a parallel path. The internationally recognized SCL Protocol defines true concurrency more precisely, as two delay events, one an Employer Risk Event and one a Contractor Risk Event, occurring and felt at the same time, and notes it is rare.
Under the SCL Protocol, contractor concurrent delay should not reduce an EOT, though this is an English-law position that parties can contract around and other jurisdictions may not follow. Compensation still requires separating employer-side costs from contractor-side costs; U.S. federal decisions such as Blinderman deny recovery to either party absent “a clear apportionment of the delay and the expense attributable to each party.”
What documentation can support a defensible TIA?
Contemporaneous updates, reports, and correspondence connect the modeled event to the project record. RP 29R-03 sets the ceiling: “The best accuracy that an analyst can hope to achieve is in the faithful reflection of the facts as represented in contemporaneous project documents, data, and witness statements.”
The internationally recognized SCL Protocol takes the same view, requiring that records “must be generated contemporaneously as the works progress, and not afterwards,” and identifying program, progress, resource, cost, correspondence, and contract documents as the categories supporting delay analysis. Daily logs can support as-built reconstruction and trace delay to its root cause.
Missing records may foreclose methods outright: RP 29R-03 states analysts cannot use observational update-based methods where only a baseline exists with no updates. Board decisions have found TIA-based expert opinions unpersuasive where the analysis omitted events central to the claimed delay or was not prepared during the course of performance. Opinions resting on missing or selectively provided records are vulnerable if opposing counsel later confronts the expert with unseen documents at deposition or trial.
What qualifications do forensic delay analysts typically hold?
Delay and disruption experts typically use CPM-based methods to quantify and allocate time impacts and to characterize delays as excusable or non-excusable and compensable or non-compensable, while damages experts separately quantify monetary consequences.
AACE International issues the Planning and Scheduling Professional (PSP) and Certified Forensic Claims Consultant (CFCC) credentials. The CFCC generally requires at least eight years of verifiable claims-related experience together with a qualifying professional certification or license, or twelve years of such experience in place of that certification.
The Project Management Institute offers the PMI Scheduling Professional (PMI-SP). Analysts may also hold Professional Engineer (PE) licensure, which may support credibility as a testifying expert who provides expert witness testimony.
Federal Rule of Evidence 702, amended effective December 1, 2023, requires the proponent to show it is more likely than not that the testimony rests on sufficient facts, reliable methods, and a reliable application of those methods; if an expert chooses a methodology to fit a desired conclusion, that choice may invite challenge.
The engagement letter identifies the expert’s role and typically defines the subject matter, assumptions, deliverables, schedule, and budget. Counsel may discuss legal proof needs and methodology options, but the expert generally selects and applies the final method.
A consulting expert may assist counsel with investigation and methodology evaluation, while a testifying expert must own and defend the opinions that support testimony, and generally cannot merely repeat a non-testifying specialist’s conclusion as the expert’s own. Disclosing material assumptions and limitations, rather than forcing a one-sided conclusion, is more credible under cross-examination.
Where TIA fits when delay claims reach dispute resolution
After completion, the schedule update selected for the TIA and the records behind each fragnet determine how much weight the analysis carries. A defensible TIA identifies the schedule update used, the fragnet inserted, the assumptions applied, and the records supporting each link.
The expert should be able to defend the records reviewed and the methodological choices made under questioning. Forum may affect presentation: a jury may need more foundational explanation, while a judge, board, or arbitration panel may move more quickly to methodology and reconciliation of competing schedules.
Missing documents and unexplained assumptions can become cross-examination points, particularly where the opinion rests on a schedule the project team did not regularly update. A clear presentation ties each disputed delay to a chronological narrative supported by schedules, RFIs, and other contemporaneous records.
Rimkus Forensic Services provides forensic delay analysis and Expert Services for construction delay matters. To discuss a schedule delay matter with the Rimkus team, contact us.
Frequently asked questions about time impact analysis
What software is used for TIA?
Analysts commonly use CPM tools such as Primavera P6, Microsoft Project, and Asta Powerproject, along with specialized forensic and schedule-analytics platforms such as Deltek Acumen Fuse and SmartPM. Schedule quality, accurate inputs, and practitioner expertise generally matter more to the result than the platform chosen.
How does TIA address resources and productivity?
TIA accounts for resource constraints and productivity only indirectly, through calendars, logic ties, or durations already embedded in the baseline schedule, and it does not independently perform resource leveling or quantify productivity variation. Practitioners generally validate resource-driven logic and may complement TIA with a separate productivity loss analysis.
How do contracts affect TIA?
Contract forms affect TIA through notice obligations, program clauses, and entitlement rules: NEC4 assesses compensation events against the Accepted Programme, while FIDIC 2017 typically imposes a 28-day notice period and an 84-day substantiation deadline. Whether missing these deadlines bars or only limits entitlement can depend on the exact wording and governing law. Float ownership and concurrency treatment also vary by contract form, so the applicable notice and entitlement rules typically shape how the analysis is presented.
This article is intended to provide general information and insights into prevailing industry practices. It is not intended to constitute, and should not be relied upon as, legal, technical, or professional advice. The content does not replace consultation with a qualified expert or professional regarding the specific facts and circumstances of any particular matter.