What is Time Variance?

Time Variance

In project management and scheduling, “time variance” refers to the difference between the planned (or estimated) duration for a task or project and the actual duration it takes to complete that task or project. It’s a measure used to determine how closely a project is adhering to its original schedule.

Time variance can be calculated using the following formula:

Time Variance (TV) = Planned Duration − Actual Duration

A positive time variance indicates that the task or project is ahead of schedule, whereas a negative time variance suggests that the task or project is behind schedule. A time variance of zero means the project is on schedule.

Example of Time Variance

Let’s explore a hypothetical example to illustrate the concept of time variance in a project management setting.

Scenario: The Office Relocation Project

Background:

XYZ Corp. is planning to relocate its main office to a larger space. The project manager, Rachel, has outlined the main tasks involved and estimated the durations for each. One of the critical tasks is the “Office Setup,” which includes setting up workstations, IT infrastructure, and other amenities. Rachel estimated that this task would take 5 days.

Actual Outcome:

When the “Office Setup” phase started, several unexpected challenges arose:

• Some of the new furniture items were damaged during transit and needed replacement.
• The IT team encountered compatibility issues while setting up the new network infrastructure.

As a result, the “Office Setup” took 8 days to complete instead of the planned 5 days.

Time Variance Calculation:

Using the formula:

Time Variance (TV) = Planned Duration − Actual Duration

Time Variance (TV) = 5 days (Planned) − 8 days (Actual)
Time Variance (TV)=−3 days

Interpretation:

The negative time variance of 3 days indicates that the “Office Setup” task took 3 days longer than initially planned. Rachel needs to assess the project’s overall timeline and determine if adjustments or additional resources are required to ensure the relocation is completed on time.

Furthermore, Rachel might hold a review meeting with her team to understand the root causes of the delay and implement lessons learned for future projects or phases.

This example underscores the importance of monitoring tasks in real-time and the value of understanding variances. By identifying such deviations early, project managers can take corrective actions to mitigate potential delays or overruns.