Schedule Variance (SV)

Schedule Variance measures schedule position in budget terms: the Earned Value to date minus the Planned Value to date. If 240,000 of work should have been complete by today but only 210,000 has been earned, SV is -30,000: a month's-end way of saying the site is 30,000 of budgeted work behind plan.

SV and the Schedule Performance Index carry the same information in different shapes - SV as an absolute gap, SPI as a ratio (EV / PV). The gap is useful for sizing recovery (how much work must be pulled forward); the ratio is useful for comparing activities or projects of different sizes.

Two caveats. SV is denominated in currency or hours, so it says nothing direct about float or the critical path - a positive SV built on easy non-critical work can mask a critical activity slipping. And like SPI, it converges to zero as the project completes regardless of how late it runs, because EV eventually reaches PV at BAC. Earned Schedule exists to fix that blind spot. Read SV alongside the programme, not instead of it.