Method selection
Choose a method by the question and the evidence
Method selection is not a ranking exercise. It is a matching exercise: the question you have to answer, against the records that actually exist, inside what the contract and the forum will accept. This page returns candidates and their disqualifying weaknesses, never a single winner.
- Jurisdiction
- General method guidance, not jurisdiction specific
- Law and editions as at
- 3 August 2026
- Last reviewed
- 3 August 2026
- Editorial status
- Editorial draft, not yet independently reviewed
Five questions, in this order
- 1
What has to be decided?
Forecast an extension of time now, explain actual completion later, evaluate a milestone, or allocate one defined event. Each points somewhere different. A contemporaneous decision points at the prospective family; a dispute years later usually demands a retrospective one.
- 2
What reliable data exist?
An accepted baseline? Native monthly updates? Actual logic? Diaries and installed quantities? If the data will not support a dynamic model, the report should say so. False precision is worse than a transparent factual analysis.
- 3
What does the contract require?
Notice, programme acceptance, update format, prospective assessment, revised programme or continuing particulars may all constrain the process. That instruction is part of the analytical question, and technical guidance cannot rewrite it.
- 4
What law and forum apply?
A court or tribunal applies its own rules of proof and expert evidence. Technical standards guide the work; they do not displace those rules.
- 5
What is proportionate?
The heavier methods cost real money. A modest dispute rarely justifies a full time-slice analysis, and a tribunal is unimpressed by a model that cost more than the sum in issue.
What the answers point at
| If this is your situation | Candidate methods | Disqualifying weakness to check first |
|---|---|---|
| Deciding an extension of time now, mid-project | Time impact analysis; contemporaneous period analysis | No validated current programme, so there is nothing to impact |
| Dispute after completion, good monthly updates exist | Windows and time-slice analysis | Updates never validated, so every slice inherits the same errors |
| Dispute after completion, updates missing but records good | As-planned versus as-built windows; as-built critical path | As-built reconstructed from the claim rather than the record |
| Tribunal wants the counterfactual tested | Collapsed as-built | Logic invented for an as-built that never had any |
| Simple works, modest sum, early view needed | Impacted as-planned, as an illustration | Presented as proof of causation when a full record exists |
| Process or infrastructure work with disciplined daily data | Daily delay measure | Gaps in the daily record turning precision into false precision |
The uncomfortable part
The method is often chosen by the records rather than by the analyst. Projects that kept a live programme and a dated site record get to use the methods tribunals find most persuasive. Projects that did not are limited to the methods that are easiest to attack, and that limitation was set years before the dispute, one unrecorded week at a time.
Whatever is chosen, the report should say which methods were considered, why the chosen one fits, what the records could not support, and what a reasonable analyst using a different method might conclude. An analysis that pretends there was only ever one option has skipped the argument it will be cross-examined on.
The eight families
- Time impact analysis: Update the programme to the moment before the event, insert the event, and measure the forecast effect.
- Impacted as-planned: Insert the delay events into the baseline programme and read off the revised completion date.
- Windows and time-slice analysis: Cut the project into consecutive periods and identify what controlled completion in each one.
- As-planned versus as-built: Compare what was planned with what happened, within periods, reasoning from the progress record.
- Collapsed as-built, or but-for analysis: Take the as-built programme, remove the delay events, and see when the works would have finished without them.
- As-built critical path and longest path: Build the as-built programme, trace the longest continuous path to completion, and identify what drove it.
- Contemporaneous period analysis: Reconstruct the decisions period by period using the programme updates and narratives that existed at the time.
- Daily delay measure: Compare planned against actual at daily resolution across a maintained as-built model.
Where the record comes in
Every mechanism on this page turns on evidence: what happened, what was known and when. A record built as the job happens is worth more than any argument assembled afterwards. Construction Metric keeps that record automatically, from the messages, photographs and voice notes a site team already sends.
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The analysis on this site is only as fast as the evidence behind it. AI Metric builds bespoke systems for consultancies, contractors and claims teams: document and correspondence triage, event registers assembled from the project record, programme and cost reconciliation, and drafting support that always cites the document it came from. Built for review by your own experts, never to replace their judgement.
Do not overread this page
This page does not select a method for your project and does not decide entitlement. The exact contract, the governing law, the facts and the forum control, and a competent analyst may reasonably reach a different selection on the same summary.
General explanation of how contract mechanisms, analysis methods and legal principles generally work. It is not legal or contractual advice, not an opinion on any project, and no standard-form contract wording is reproduced anywhere on this site. Standard forms are routinely amended, so every default described here, including every time period, can be different on your project. Your executed contract, as amended, and the governing law and forum always control. Deadlines may already be running: if an event has occurred, preserve your position and take qualified advice.