Learning Center
The SCL Protocol, Method by Method
The Society of Construction Law’s Delay and Disruption Protocol is the closest thing the industry has to a shared reference point for how delay analysis methods relate to each other. This is a plain-language map of its structure -- for the Protocol’s actual text, go to the source directly.
What the Protocol Actually Is
First published in 2002 and revised since, the Protocol is guidance produced by the Society of Construction Law (a UK- based professional body) aimed at giving the construction industry a common vocabulary and a common set of recognized approaches for analyzing delay and disruption. It is not a contract, a statute, or a set of binding rules -- a contract has to expressly adopt it for its recommendations to carry contractual weight, though its terminology and method names are now widely understood and cited even where it hasn’t been formally incorporated.
Its central, most-cited principle is straightforward: as-planned programmes should be updated to reflect actual progress, and delay analysis should be based on the schedule as it actually existed at the relevant time -- a preference for contemporaneous, real records over reconstructions built long after the fact wherever possible.
The Recognized Methods
The Protocol groups delay analysis methods broadly into prospective (analyzing forward from a point in time, before the outcome is known) and retrospective (analyzing after the fact, using the real as-built record). Method choice depends on the facts available, the contract terms, the size of the dispute, and the forum -- the Protocol is explicit that no single method is correct for every case.
Impacted As-Planned
Prospective. Used when only the original baseline is reliable or available -- inserts the delay event into the unprogressed baseline network.
Read the full worked example →Time Impact Analysis
Prospective, contemporaneous. Inserts the delay event into the schedule update immediately before the event occurred -- widely regarded as one of the more defensible methods where a good contemporaneous update exists.
Read the full worked example →Time Slice (Windows) Analysis
Retrospective. Divides the project into consecutive windows and identifies what was actually driving the critical path within each one.
Read the full worked example →As-Planned vs. As-Built
Retrospective, simplest. Compares planned and actual dates directly -- useful as a first look, but on its own can't distinguish real delay from float absorption.
Read the full worked example →Collapsed As-Built
Retrospective. Removes specific delay events from the real as-built record and re-links the network to see what would have happened without them.
Read the full worked example →Longest Path Analysis
Retrospective. Traces the longest continuous chain of as-built activities backward from actual completion, rather than relying on any single update's own critical-path flag.
Disruption, Kept Separate From Delay
The Protocol also treats loss of productivity (“disruption”) as a distinct category from schedule delay -- a project can be disrupted (working less efficiently than planned) without necessarily finishing late, and a measured mile analysis is the method it most closely associates with quantifying that loss.
Whichever method a given dispute calls for, they all depend on the same raw material: accurate schedule data at specific points in time. Claims Digger keeps every schedule update you upload as its own snapshot, so choosing the right method is a matter of picking the right comparison, not reconstructing lost records first. See how it works.
Frequently Asked Questions
- Is the SCL Protocol legally binding?
- No -- it's guidance, not law or a contract term, unless a specific contract expressly incorporates it. Its influence comes from wide industry recognition of its methods and terminology, not from any statutory or regulatory force.
- Does the Protocol say one method is always correct?
- No. It's explicit that method choice depends on the facts available (what records exist), the terms of the contract, the size of the dispute, and the forum it will be argued in -- there's no single 'right' method for every case.
- Where can I read the actual Protocol?
- The Society of Construction Law publishes it directly -- search for the current edition on the SCL's own website. This page summarizes its structure and doesn't reproduce its text.
Part of the Claims Digger Learning Center. Related reading: AACE RP 29R-03, illustrated · SCL Protocol (glossary)