1. The challenge

Complex projects are seldom finished on the original date. Total delay is easy to measure (as-built vs contractual duration) — but who is responsible, and for what portion, is never easy. Pair this Short with Short #1 (entitlement) and Short #2 (calculation).

2. Why EOT clauses exist

  • Retain a defined completion date — keep the contract live.
  • Protect liquidated damages — preserve the owner's right to LAD for contractor delay.
  • Contractor relief — relief from strict completion duties and, sometimes, money.

3. Notice rules differ by country

England

Late architect/engineer responses tolerated; strict notice compliance not always fatal.

Australia

Certifiers must decide promptly.

USA

Withholding justified extensions while pressing completion can equal an acceleration order; oral notice and CPM updates accepted as evidence.

Canada

Notice viewed strictly — but compensation was still awarded where the clause barred only time, not costs.

4. Classes of delay

  • Contractor-caused — no EOT; accelerate at own cost.
  • Neutral — time but no money.
  • Owner-caused — time plus money.

They rarely occur alone — concurrency is what makes analysis complex.

5. The critical path moves

Only critical-path delays count — but the critical path is dynamic: resourcing, productivity and re-sequencing shift it repeatedly. Courts limit entitlement to actual duration minus what it would have been but for excusable delays. Blindly trusting computer-generated schedules (including trivial activities) is a classic error.

6. CPM: preferred, with conditions

  • Bar charts rejected — they cannot show logic links or critical-path impact.
  • Retrospective CPM allowed — only if it adopts all governing features of the original plan.
  • CPM not always mandatory — accurate measurement of the delay differential matters more than the tool.

7. When CPM falls short

On linear jobs (pipelines, tunnelling, highways) or resource-driven finishing phases, bar charts or line-of-balance can be equally effective — and far cheaper than reconstructing as-built networks from poor records. Not necessarily CPM, but CPM if necessary — and only a properly maintained, current schedule.

8. Progress curves: the practical alternative

1
Plot planned vs actual

Physical and financial curves reveal gains, losses and productivity.

2
Find the guilty trade

Repeat per major trade; compare preceding and succeeding trades.

3
Annotate history

Overlay drawing issues, approvals, daily reports, minutes.

4
Start here even on big jobs

Isolate the time frames and trades needing deep analysis first.

9. Schedules must be dynamic

A static, never-updated programme is "of little use to measure delays." Over-specified networks (3,000–4,000 activities) that cannot be updated monthly invite lip service. Update consistently, grant recognised extensions promptly, and keep the projected completion honest.

10. Concurrency can be apportioned

Where overlapping delays can be objectively separated, most tribunals now apportion responsibility rather than denying everything. Time extensions were granted for government delay even alongside contractor delay — in different periods — with overlap handled objectively, not by simple addition.

11. Window (snapshot) analysis: the standard

1
As-planned baseline

Fix the starting programme.

2
Apply first impact

Insert the earliest event chronologically.

3
Revise to adjusted

Re-schedule with the impact.

4
Repeat

Apply each later impact in turn, at 1–6 month windows.

The older "entitlement" and "impacted as-planned" methods are no longer acceptable — they are not dynamic. "But for" collapsing may supplement but rarely stands alone. And remember: a computer analysis is no better than its input data — understand float correctly.

12. Takeaways

  • Notices are critical — non-compliance can kill all protection.
  • CPM when necessary — dynamic and current beats any static chart.
  • Snapshot analysis preferred — window by window, chronologically.
  • Apportion concurrency — objectively, where separable.

This Short presents general guidance for educational purposes and does not constitute professional advice.

Frequently asked questions

Which delay analysis method do courts prefer?
Dynamic CPM with window/snapshot analysis. Bar charts are rejected; entitlement and impacted-as-planned are obsolete.
Does the critical path stay fixed?
No — it shifts with resourcing and sequencing. Only delays on the current critical path count.
Can concurrent delays be apportioned?
Yes, where separable objectively — most tribunals now apportion rather than deny.
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