Revision control

Every controlled document carries a revision code, an issue status, and a revision history recording what changed, when, by whom and why; a document management system or register tracks which revision is current and who holds copies; superseded revisions are marked or withdrawn. The machinery is unglamorous and universal, because every downstream activity — estimating, review, procurement, construction — is only correct with respect to a specific revision.

Which is the point: nearly every documentation failure in this glossary is a revision-control failure wearing a costume. The estimate built on the superseded drawing, the compliance check against the outdated standard, the site working from last month's print, the two disciplines resolving the same interface differently — all of them are, mechanically, someone consuming revision N while the truth moved to N+1.

Control degrades at the edges: the uncontrolled copy saved to a desktop, the marked-up PDF emailed outside the system, the vendor working from the revision attached to the purchase order months ago. The system knows what is current; the project runs on what people actually have open — and closing that gap is a permanent, manual, repeated effort on every project that has ever existed.