Source: https://www.quantsurv.com/library/glossary/critical-path
Content format: Markdown version of the public page.
Content reviewed: 2026-10-12

# Critical path

The sequence of activities that determines the earliest completion of the work or milestone being analysed, using the programme’s logic, durations and constraints.

by [Jack Butler-Kettle](<https://www.quantsurv.com/about#jack-butler-kettle>) · About 2 min readShare

## Further detail

Read this alongside [SCL Delay and Disruption Protocol](<https://www.scl.org.uk/sites/default/files/documents/SCL_Delay_Protocol_2nd_Edition_Final.pdf>).

A critical-path assessment explains which activities control the completion being tested. The result depends on reliable logic, durations, calendars, constraints and recorded progress. A coloured bar in a programme is not enough to establish why completion moved. Critical activities may change as work progresses, and more than one path may be critical.

Identify the programme version and progress date, then test the event against the activities and milestone it affects. Keep the programme and actual records together. The [delay and disruption comparison](<https://www.quantsurv.com/library/delay-and-disruption>) distinguishes time effects from productivity and cost effects. For the commercial cost consequences of a programme event, [Delay and disruption cost recovery](<https://www.quantsurv.com/claims?service=%2Fdelay-and-disruption%2Fservices%2Fdelay-disruption-recovery#client-types>) connects the claimed loss to supporting records and the applicable contract.

## Sources

1.  [Delay and Disruption Protocol, 2nd edition, February 2017](<https://www.scl.org.uk/sites/default/files/documents/SCL_Delay_Protocol_2nd_Edition_Final.pdf>). Society of Construction Law.

### Programme and progress example

Replace the simple sequence with the project programme and logic. Explain actual progress, remaining work, mitigation and other causes before assessing completion impact.

[Download blank Excel workbook](<https://www.quantsurv.com/downloads/library/programme-and-progress-example.xlsx>)

Free blank template for your own project. The completed example is shown below. No email address required.

View the completed example

Completed fictional example

Westhaven refurbishment · 14 October 2026 · Version 1.0

#### Programme and progress example

Scroll across if needed to read the whole record. A dash means no value has been entered.

Programme and progress example: completed fictional example
| Activity | Predecessor | Baseline start | Baseline finish | Actual / forecast finish | Progress evidence | Assessment |
| --- | --- | --- | --- | --- | --- | --- |
| A-100 access release | None | 7 Oct 2026 | 7 Oct 2026 | 8 Oct 2026 | AL-07/08 | Access restored 8 Oct 10:00 |
| A-120 partitions | A-100 | 7 Oct 2026 | 12 Oct 2026 | 14 Oct 2026 forecast | D-07/08; updated quantities | Resequencing partly mitigates interruption |
| A-140 services | A-120 | 13 Oct 2026 | 16 Oct 2026 | 18 Oct 2026 forecast | Planner update P-03 | Check available float and other constraints |

This is an editable sequence illustration, not a critical-path analysis or a finding that an extension of time is due.

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