In accordance with the PMBOKGuide and the standard practices for Earned Value Management (EVM), Schedule Variance (SV) is a measure of schedule performance expressed as the difference between the earned value and the planned value.
* The Formula:
$$SV = EV - PV$$
* EV (Earned Value): The measure of work performed expressed in terms of the budget authorized for that work.
* PV (Planned Value): The authorized budget assigned to scheduled work.
* Interpretation of Results:
* Positive SV ($ > 0$): Indicates that the project is ahead of schedule (more work has been earned than was planned).
* Negative SV ($ < 0$): Indicates that the project is behind schedule (less work has been earned than was planned).
* Zero SV ($= 0$): Indicates that the project is exactly on schedule.
* Comparison with Other Options:
* EV less AC (A): This is the formula for Cost Variance (CV) ($CV = EV - AC$). It measures cost performance.
* AC less PV (B): This is not a standard EVM metric used for performance measurement.
* AC less EV (D): This is essentially the inverse of Cost Variance and is not a standard project management formula.
In the Control Schedule process, SV is a critical indicator used to determine if the project is deviating from the schedule baseline and if corrective or preventive actions are required.