Critical path and float without the jargon

The path the software calculates

A scheduling tool calculates criticality from the logic, durations, calendars and constraints it has been given. Change any of those and the calculated path changes. That is not a flaw, but it does mean the red bars are an output of the model rather than a fact about the project.

The path the site was actually on

Logic changes. Resources move. Access constraints appear. Contractors resequence. Near-critical work becomes critical. A programme can contain constraints or settings that make a path look critical while the site was working somewhere else entirely.

The analyst therefore tests the calculated path against the factual one: what were site managers prioritising and why, which missing design or access or material constrained the next operation, what do the quantities and resources show, do the minutes and look-aheads identify the same priority, and did the apparent constraint really govern or was it an artefact of the model.

Float

Float is the amount of time an activity can slip before it affects something that matters. Total float measures slack against the completion date; free float measures slack before the next activity is affected. Both are properties of the model, so both change every time the model changes.

Technical guidance The Society of Construction Law Protocol’s starting position is that, unless the contract says otherwise, float is not owned exclusively by either party and is broadly available to the project, with entitlement questions biting when employer delay pushes completion beyond the contractual date. That is guidance, and amendments frequently take a different position.

In practice the float question is a drafting question. Clauses that allocate float to the employer, or that require the contractor to absorb delay while float remains, are common. Read the contract before reading anything else about float, including this page.

Pacing

Pacing is the deliberate slowing of work in response to a delay elsewhere, on the reasoning that there is no point racing to a gate that is already shut. It is legitimate in principle and frequently indistinguishable, in a bare programme, from contractor delay. What separates them is contemporaneous evidence of the decision, which is another reason narratives and minutes matter.