Project Planning & Scheduling

Schedule Variance

Schedule Variance: Keeping Your Project on Track

In project planning and scheduling, staying on schedule is crucial for success. A key metric for measuring this progress is Schedule Variance (SV). This article will demystify the concept of schedule variance, explaining its calculation, interpretation, and significance.

What is Schedule Variance?

Schedule Variance is the difference between the planned or projected duration of an activity and its actual duration. It provides a clear picture of whether an activity is ahead, behind, or on schedule.

Calculating Schedule Variance:

SV = Planned Duration - Actual Duration

Interpretation:

  • Positive SV: The activity is ahead of schedule.
  • Negative SV: The activity is behind schedule.
  • Zero SV: The activity is on schedule.

Example:

Let's say you planned for a software development task to take 10 days. However, the actual time taken was 8 days.

SV = 10 days - 8 days = 2 days

This positive schedule variance indicates that the task was completed 2 days ahead of schedule.

Beyond Activity Duration: Schedule Variance and Project Dates

While schedule variance focuses on individual activities, it also extends to the overall project schedule. We can analyze the difference between projected start and finish dates and their actual or revised counterparts.

Projected vs. Actual Dates:

  • Start Date Variance: Difference between the projected start date and the actual start date.
  • Finish Date Variance: Difference between the projected finish date and the actual finish date.

Example:

If a project was initially planned to start on January 1st and finish on February 15th, but it actually started on January 10th and finished on February 20th, we can analyze the following:

  • Start Date Variance: January 10th - January 1st = 9 days (negative, project started late)
  • Finish Date Variance: February 20th - February 15th = 5 days (negative, project finished late)

Importance of Schedule Variance:

Understanding schedule variance is essential for effective project management. It enables:

  • Early identification of delays: By monitoring SV regularly, you can detect potential problems before they escalate.
  • Proactive action: Negative schedule variance signals the need for corrective measures to get back on track.
  • Informed decision-making: SV helps you prioritize tasks, allocate resources efficiently, and communicate progress effectively.
  • Improved project forecasting: Understanding past schedule variance can improve future project estimations.

Conclusion:

Schedule variance is a crucial metric for assessing project progress. By understanding the difference between planned and actual durations, as well as projected and actual dates, project managers can gain valuable insights into project performance, enabling them to take timely action and deliver successful outcomes.


Test Your Knowledge

Schedule Variance Quiz

Instructions: Choose the best answer for each question.

1. What does Schedule Variance (SV) measure?

a) The difference between the planned budget and the actual cost.

Answer

Incorrect. This describes Cost Variance, not Schedule Variance.

b) The difference between the planned duration of an activity and its actual duration.

Answer

Correct! This is the definition of Schedule Variance.

c) The number of days a project is ahead or behind schedule.

Answer

Incorrect. While SV can indicate how many days a project is ahead or behind, it's the metric used to calculate this.

d) The difference between the planned start date and the actual start date.

Answer

Incorrect. This specifically refers to the Start Date Variance, a component of Schedule Variance.

2. A positive Schedule Variance means:

a) The activity is behind schedule.

Answer

Incorrect. A positive SV means the activity is ahead of schedule.

b) The activity is on schedule.

Answer

Incorrect. A zero SV indicates the activity is on schedule.

c) The activity is ahead of schedule.

Answer

Correct. A positive SV indicates the activity is completed earlier than planned.

d) The activity is completed with a lower cost than planned.

Answer

Incorrect. This refers to Cost Variance, not Schedule Variance.

3. A task was planned to take 5 days but was completed in 7 days. What is the Schedule Variance?

a) 2 days

Answer

Correct. SV = Planned Duration - Actual Duration = 5 days - 7 days = -2 days.

b) -2 days

Answer

Correct. SV = Planned Duration - Actual Duration = 5 days - 7 days = -2 days.

c) 12 days

Answer

Incorrect. This is not the correct calculation of Schedule Variance.

d) 0 days

Answer

Incorrect. A Schedule Variance of 0 would mean the task was completed on schedule.

4. Which of the following is NOT a benefit of understanding Schedule Variance?

a) Early identification of delays.

Answer

Incorrect. This is a significant benefit of understanding SV.

b) Proactive action to address issues.

Answer

Incorrect. This is a major benefit of understanding SV.

c) Determining the project's budget.

Answer

Correct. Schedule Variance doesn't directly determine the project's budget. Cost Variance is used for that.

d) Improved project forecasting.

Answer

Incorrect. This is a valuable benefit of understanding SV.

5. A project was planned to start on March 1st and finish on April 15th. It actually started on March 5th and finished on April 20th. What is the Finish Date Variance?

a) 5 days

Answer

Correct. Finish Date Variance = Actual Finish Date - Planned Finish Date = April 20th - April 15th = 5 days.

b) -5 days

Answer

Incorrect. The project finished later than planned, so the variance is positive.

c) 4 days

Answer

Incorrect. This is not the correct calculation of the Finish Date Variance.

d) -4 days

Answer

Incorrect. The project finished later than planned, so the variance is positive.

Schedule Variance Exercise

Scenario: You are managing a website redesign project. The planned duration for the development phase was 14 days. The actual duration was 18 days.

Task:

  1. Calculate the Schedule Variance (SV) for the development phase.
  2. Interpret the result: Is the development phase ahead of schedule, behind schedule, or on schedule?
  3. What are some potential causes for this Schedule Variance?
  4. Suggest at least one corrective action you could take to address the situation.

Exercice Correction

1. Schedule Variance (SV): SV = Planned Duration - Actual Duration SV = 14 days - 18 days = -4 days 2. Interpretation: The development phase is behind schedule by 4 days. A negative SV indicates a delay. 3. Potential Causes: * Unexpected technical challenges * Unforeseen dependencies * Resource constraints (e.g., lack of available developers) * Changes in scope or requirements 4. Corrective Action: * Review the project scope and identify opportunities for streamlining or reducing complexity. * Allocate additional resources or adjust the team's workload to compensate for the delay. * Communicate the delay to stakeholders and adjust project deadlines as needed.


Books

  • Project Management Institute (PMI). (2021). A Guide to the Project Management Body of Knowledge (PMBOK® Guide) - Seventh Edition. Project Management Institute. This comprehensive guide covers various project management concepts, including schedule management and variance analysis.
  • Kerzner, H. (2017). Project Management: A Systems Approach to Planning, Scheduling, and Controlling. John Wiley & Sons. Provides in-depth coverage of project scheduling, including schedule variance and its importance in project control.
  • Meredith, J. R., & Mantel, S. J. (2019). Project Management: A Managerial Approach. John Wiley & Sons. This book offers a thorough explanation of project scheduling techniques and the analysis of schedule variance.

Articles


Online Resources

  • ProjectManagement.com: https://www.projectmanagement.com/ This website offers numerous articles and resources related to project management, including schedule management and variance analysis.
  • ProjectManager.com: https://www.projectmanager.com/ Offers articles, tutorials, and tools for project managers, covering schedule variance and other relevant topics.

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Project Planning & Scheduling
Cost Estimation & Control
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