Contract Execution
The point at which every party to a contract has signed it, making it legally binding, which is a different event from the work under that contract actually starting.
Why it matters
A contract can be fully executed, meaning signed and legally binding, and still sit for weeks before the schedule clock that governs the work actually starts, which is usually [[concept-notice-to-proceed|Notice to Proceed]] instead. Confusing execution with the start of work is a common source of schedule disputes.
On a real project
A subcontract gets fully executed, signed by both the general contractor and the subcontractor, on March 1st, but the subcontractor's actual notice to proceed doesn't arrive until April 15th, once the site is ready for that scope of work. The subcontractor's schedule obligations run from the notice to proceed date, not the execution date.
Who this matters most to
A Contracts Administrator tracks exactly when every contract on a project reaches execution, since that date starts the clock on certain contractual obligations even when physical work doesn't begin for weeks afterward.
Where this goes wrong
A subcontractor assumes its schedule obligations start the day its contract is executed, rather than the later date it actually receives notice to proceed. It mobilizes a crew too early, sits idle waiting for the site to be ready, and disputes who should absorb that cost.