A Schedule Variance ( SV) threshold value is expressed as a monetary value. An issue is generated if the Schedule Variance (the difference between the activity's earned value and the work scheduled to be performed) falls beyond the threshold values.
Schedule Variance is calculated as SV = Earned Value Cost – Planned Value Cost. A negative value indicates that less work was actually performed than was scheduled. The activity may be considered behind schedule.
If the lower threshold value is 0, an issue is generated as soon as the earned value of the work performed is equal to or less than the amount of work that was supposed to be performed, according to the schedule. A larger negative value for a Schedule Variance threshold indicates that an activity may be behind schedule by that amount before an issue is generated.