Earned schedule

Earned schedule is a time-based extension of earned value management that measures schedule performance in units of time rather than dollars. Traditional earned value expresses schedule variance in cost terms (SV) and its schedule performance index (SPI) drifts back toward 1.0 as any project — even a late one — approaches completion, which makes it unreliable late in the job. Earned schedule fixes this by asking when the value earned to date was planned to be earned, producing time-based metrics: SV(t), the schedule variance in days or weeks, and SPI(t), a performance index that stays honest through project completion. The result is a more accurate read of whether a project is ahead or behind, and by how much time, which is what owners and project teams actually want to know.

Related term: CPM (critical path method) scheduling