Definition: Schedule Variance (SV)is the difference between Earned Value and Planned Value, and it shows how much the project is ahead or behind schedule in terms of dollars.
The term “Schedule Variance” is popularized by the PMI. Per the PMBOK Guide, “Schedule variance (SV) is a measure of schedule performance expressed as the difference between the earned value and the planned value. It is the amount by which the project is ahead or behind the planned delivery date at a given point in time.”
进度偏差的一部分earned value management.
时间表差异（SV）公式
The formula to calculate SV is given below:
时间表差异=赚值（EV） - 计划的价值（PV）
赚取的价值是完整工作的价值。
Planned Value is the value of work that you should earn according to the plan.
If the SV is positive, the project is ahead of schedule and performing well. An SV is negative; the project is behind schedule and needs corrective actions to bring the project on track. An SV value equal to zero shows the project is on schedule.
您可能会想知道，如果计划绩效指数提供相同的信息，为什么需要计划方差。但是，首先，了解SPI在百分比和差异方面提供效率，并以美元术语提供数据。
这两个参数都提供了类似的信息，但具有不同的指标。
安排差异示例与计算
示例1
For a project, the earned value is 40,000, and the planned value is 45,000 USD. Calculate the schedule variance.
SV = EV - PV
= 40,000 - 45,000
= –5,000 USD
由于SV是负面的，因此该项目落后于计划。
示例2
对于一个项目，赚取的价值为45,000，计划的价值为40,000美元。计算时间表差异。
SV = EV - AC
= 45,000 - 40,000
= 5,000 USD
Since the SV is positive, the project is ahead of schedule.
概括
时间表差异（SV）显示该项目是否在计划前面还是落后。如果差异超出了可接受的限制，则项目经理将找到这种差异的根本原因，并采取纠正措施以计划将项目带来。
从PMP考试的角度来看，此公式和计算很重要。在PMP考试中，您可能会看到一些问题，要求进行时间表差异计算。
