Lead time is the elapsed time between a defined starting event and a defined completion event in a process, including processing and waiting. In construction bidding, those events might be receipt of an invitation to tender and confirmation that the proposal has been submitted.
The endpoint determines which management question the measure answers. An estimating team investigating preparation delays can measure readiness lead time, ending when the proposal is approved for submission. Submission lead time continues until confirmed delivery. A completed proposal held until the client’s deadline therefore accumulates submission lead time after preparation has finished.
Measurement requires an agreed time basis, such as calendar hours or working hours. A proposal received on Friday and approved on Monday produces different values under those conventions. Approval withdrawals also need explicit treatment: the record should preserve the initial approval event and identify subsequent rework. Staff effort is measured separately because several estimators can work concurrently within the same elapsed interval.
Within DMAIC, lead time provides a baseline in Measure and an outcome measure for an Improve pilot. Value Stream Mapping locates processing and waiting within that interval. Operational definitions establish consistent event boundaries, while control charts can track lead time across comparable proposals. Tender complexity and procurement route should remain visible when interpreting changes, since a shift toward smaller bids can lower observed lead time without any change to the estimating process.
