Delay analysis methodologiesin construction.
A 2026 reference on forensic schedule analysis. TIA, Window Analysis, As-Planned vs As-Built, Collapsed As-Built, concurrent delay doctrine, and the Eichleay formula for delay claims.
Delay analysis in construction is the forensic discipline of attributing project delays to responsible parties using accepted schedule methodologies. Four primary methodologies are recognized in AACE International Recommended Practice 29R-03: Time Impact Analysis (prospective, single-event), As-Planned vs As-Built (static comparison), Window Analysis (the most rigorous, period-by-period), and Collapsed As-Built (retrospective subtraction). Each methodology has a defined use case, evidentiary weight, and cost. Selecting the wrong methodology can defeat an otherwise valid delay claim.
The four delay analysis methodologies
AACE International RP 29R-03 (Forensic Schedule Analysis) is the standard reference for delay analysis methodology selection. Each method has a defined scope, pros, cons, and evidentiary weight in dispute resolution.
TIA
AACE RP 29R-03 / 52R-06Time Impact Analysis
- When used
- Prospective. Contemporaneous evaluation of a single change or delay event during the project.
- Pros
- Forward-looking, widely accepted for change orders, uses contemporaneous schedule data, fragnet methodology is well-defined in AACE RP 52R-06.
- Cons
- Quality depends on the integrity of the baseline being impacted. Single-event focus is poorly suited to cumulative or interactive delays.
Static
AACE RP 29R-03As-Planned vs As-Built
- When used
- Retrospective. Simple comparison of original baseline schedule to final as-built schedule.
- Pros
- Easy to perform. Useful as a first-look summary. Acceptable for small disputes where contemporaneous updates are unavailable.
- Cons
- Ignores intermediate schedule updates, cannot attribute delays to specific parties or windows, generally given less evidentiary weight by courts.
Update/Snapshot
AACE RP 29R-03 (preferred)Window Analysis
- When used
- Retrospective. Project divided into time windows (typically monthly) analyzed against contemporaneous schedule updates.
- Pros
- Most rigorous methodology. Uses contemporaneous data, isolates delay events by window, captures cumulative effect, identifies the responsible party for each window.
- Cons
- Requires reliable contemporaneous schedule updates. More expensive and time-consuming than other methods. Window definitions can be disputed.
CAB
AACE RP 29R-03Collapsed As-Built
- When used
- Retrospective and post-completion. Starts from as-built, removes delays one at a time.
- Pros
- Works without contemporaneous schedule updates. Useful for legacy disputes where updates are missing. Provides counterfactual completion dates.
- Cons
- Sensitive to the order delays are removed. Less favored by courts than Window Analysis. Cannot capture concurrent delay interaction cleanly.
Delay classification matrix
Every delay falls into one of three categories. The classification determines whether the contractor gets a time extension, monetary compensation, both, or neither. Liquidated damages flow to the owner only on non-excusable delay.
Non-excusable
Contractor-caused
- Time extension
- No
- Compensation
- No
- Liquidated damages
- Yes
Late submittals, crew under-staffing, contractor coordination failures, missed deliveries the contractor controls.
Excusable non-compensable
Force majeure, unusual weather, owner-caused but contract bars compensation
- Time extension
- Yes
- Compensation
- No
- Liquidated damages
- No
Hurricanes, exceptional weather days beyond contract allowance, government-imposed shutdowns, third-party utility delays.
Excusable compensable
Owner-caused
- Time extension
- Yes
- Compensation
- Yes
- Liquidated damages
- No
Late owner-furnished items, differing site conditions, design errors, late permit issuance, owner-directed changes without time impact agreement.
How to perform Window Analysis
Window Analysis is the most rigorous methodology and the one most preferred by courts and arbitrators. Five steps from window definition through cumulative impact calculation.
- 1
Define the windows
Divide the project into discrete time windows, typically monthly.
Each window begins at the data date of one schedule update and ends at the data date of the next. Monthly windows are the most common because they align with standard monthly schedule update cycles in commercial construction contracts. Document every window start and end date before any analysis begins. The window structure must be defensible if challenged.
- 2
Identify the contemporaneous schedule for each window
For each window, anchor to the most recent approved schedule update at the start of the window.
This is the contemporaneous schedule against which actual progress in that window will be compared. If a schedule update is missing for a critical period, the analysis must reconstruct one from project records (daily reports, payment applications, photographs, RFIs). A reconstructed update is weaker evidence than an approved one.
- 3
Compare planned vs actual within each window
For every activity active during the window, measure the gap between planned and actual progress.
Identify activities that slipped, activities that consumed float, and any changes to the critical path. Record the responsible party for each delay event based on contract terms. Where the critical path shifted during the window, document why. Tie every observation to source data (daily reports, RFIs, photos, weather records).
- 4
Account for concurrent delays
Identify whether multiple parties caused critical-path delays in the same window.
If concurrent delay exists, apply the contractual or jurisdictional rule. Under US doctrine, truly concurrent delay typically means neither party recovers. Under UK SCL Protocol rules, apportionment is permitted. Document the precise timing of each delay event and which party had the capability to mitigate. Concurrency is decided window by window, not for the whole project.
- 5
Calculate cumulative impact and entitlement
Sum net excusable delay across all windows and calculate compensation.
Distinguish excusable compensable from excusable non-compensable. Calculate direct costs (extended general conditions, escalation, idle equipment) for the delay period. Apply the Eichleay formula or the contract-specified HOOH method for unabsorbed home office overhead. Document the methodology in a forensic schedule report citing AACE RP 29R-03.
Worked example: public school delay claim
A $24M public school project, original contract duration 18 months. The owner delays issuance of the building permit by 47 days during the foundation phase. The contractor selects Window Analysis as the methodology and engages a forensic scheduler.
Owner-caused permit delay impacts critical-path foundation activity.
Contractor was behind on shop drawing submittals during the same window.
47 owner days minus 12 concurrent contractor days = 35 days net entitlement.
35 days at $1,840 per day unabsorbed home office overhead.
The contractor recovered net entitlement only after acknowledging the 12-day concurrent delay. Had the contractor claimed all 47 days and ignored the concurrency, the owner would have introduced contemporaneous evidence of the shop drawing slippage and likely defeated the claim entirely. Honest concurrency analysis is the difference between a recoverable claim and a contested one.
Side-by-side methodology comparison
Each methodology answers a different question and carries a different cost. Use this table to select the right approach for a specific claim or to test the methodology an opposing party has chosen.
| Attribute | TIA | Static | Window | CAB |
|---|---|---|---|---|
| Direction | Prospective | Retrospective | Retrospective | Retrospective |
| When performed | During project | After completion | After completion | After completion |
| Uses contemporaneous updates | Yes (baseline) | No | Yes (every window) | Optional |
| Best for | Single change orders | Quick summary | Complex multi-party delays | Post-completion claims |
| Court/arbitrator weight | High for changes | Low | Highest | Moderate |
| Cost to perform | Moderate | Low | High | Moderate |
| Captures concurrent delay | Limited | No | Yes | Limited |
Concurrent delay and the Eichleay formula
Concurrent delay arises when both the owner and contractor cause delay on critical-path activities during the same window. Under prevailing US doctrine, truly concurrent delay typically means neither party recovers: the contractor cannot collect compensation and the owner cannot assess liquidated damages. The UK Society of Construction Law Delay and Disruption Protocol (2nd Edition) takes a more nuanced position and allows apportionment based on which party caused the delay first and which had the capability to mitigate. Documentation of timing, causation, and mitigation capability decides concurrency disputes.
The Eichleay formula calculates recovery of unabsorbed home office overhead on owner-caused delay. It originates from the 1960 decision in Eichleay Corp. v. United States, 60-2 BCA P 2,688.
times total HO overhead during contract
times (delay days / contract days)
Eichleay applies only when extended delay prevents the contractor from bidding on or performing replacement work. Federal courts and boards apply specific tests: the contractor must have been on standby, the standby must have been driven by the owner-caused delay, and the contractor must have been unable to take on substitute work. State courts vary on Eichleay application and some have replaced it with daily-rate or actual-cost formulas.
Five mistakes that defeat delay claims
These are the most common reasons otherwise valid delay claims fail in arbitration and court. Each one is preventable with discipline at the project level.
- 01
Late notice of delay
Most contracts require notice within 7 to 14 days of the delay event. AIA A201-2017 Section 15.1.3 sets a 21-day window. Late notice is a common defense and can void otherwise valid entitlement. Daily reports help establish when the contractor first recognized the impact.
- 02
Using an unapproved baseline
TIA and Window Analysis require an approved baseline schedule as the anchor. Analyses built on an unapproved or unilaterally revised baseline are routinely rejected. Confirm the baseline is the contract-approved one before any methodology work begins.
- 03
Ignoring concurrent contractor delays
Many contractor claims attribute all delay to the owner while ignoring concurrent contractor-caused delay in the same window. A defensible analysis identifies and quantifies concurrent delay rather than papering over it. Failure to do so undermines credibility with arbitrators and courts.
- 04
Mixing direct and indirect costs incorrectly
Direct delay costs (extended general conditions, escalation, idle equipment) are different from unabsorbed home office overhead. The Eichleay formula applies only to unabsorbed HOOH and only when the contractor was on standby unable to take on replacement work. Mixing the categories is a frequent claim defect.
- 05
Relying solely on As-Planned vs As-Built
A simple as-planned versus as-built comparison is the weakest forensic methodology. It cannot attribute delays to specific parties or windows. When contemporaneous schedule updates exist, Window Analysis is the defensible choice. Use As-Planned vs As-Built only as a summary, never as the sole methodology in a contested claim.
Reference values and timing
Notice windows, methodology guidance, and standard-reference values cited in delay analysis. Numbers below are sourced from AACE, AIA, and the original Eichleay decision.
Frequently asked questions
Forensic schedule analysis is only as strong as the contemporaneous evidence behind it. Late notice, missing daily reports, and uncontested concurrent delay are the three failures that defeat most claims. Plan of Day is voice-first construction reporting that captures field events the day they happen: weather, delivery delays, RFI impacts, crew utilization, owner direction, and the decisions that later become exhibits in a delay claim. Specialized AI agents tag potential delay events as they appear in field reports and surface them to the project team within minutes rather than weeks. Daily reports become contemporaneous evidence by default, not by accident.
Further reading
Critical Path Method in Construction
The scheduling discipline that underpins every delay analysis methodology. CPM logic, float, and how the critical path actually moves.
Earned Value Management in Construction
CPI, SPI, and forecasting cost and schedule performance. EVM and delay analysis are complementary disciplines.
Construction Daily Report — Legal Requirements
Contemporaneous daily reports are the single most important evidence in delay claims. What courts require and what defeats claims.
Construction Daily Report Guide
How field-level daily reporting captures the events that later become delay analysis evidence.
Sources
- AACE International Recommended Practice 29R-03 — Forensic Schedule Analysis. Defines the four primary delay analysis methodologies and selection criteria.
- AACE International Recommended Practice 52R-06 — Time Impact Analysis As Applied in CPM Scheduling. Standard reference for TIA fragnet construction and application.
- SCL Delay and Disruption Protocol, 2nd Edition — UK Society of Construction Law. The leading international reference on concurrent delay and apportionment.
- Eichleay Corp. v. United States, 60-2 BCA P 2,688 (Armed Services Board of Contract Appeals 1960) — original case establishing the unabsorbed home office overhead formula.
- AIA A201-2017 — General Conditions of the Contract for Construction, Section 15.1 (Claims and Disputes). 21-day notice requirement.
- ASCE Standard Practice for the Scheduling of Construction Projects — American Society of Civil Engineers reference on CPM scheduling discipline.
- NOAA National Centers for Environmental Information — authoritative weather data for delay-claim substantiation under Federal Rules of Evidence 803(8).