PM-Foundations – Using Earned Value to Identify Budget Variances

Within the world of IT projects, labor generally represents the largest and most complex component of the overall project budget. As a result, the development of the project schedule is a major driver in creating the project budget. Deliverables and activities are identified and sequenced, resources are estimated, and the project timeline is established. The project staffing plan is created from the resources loaded in the project schedule, and this staffing plan generally represents the largest component of the overall project budget. Ironically, after the project budget is created using the project schedule as a primary source of information, project managers often disconnect the linkage between the schedule and the budget when analyzing these two critical project artifacts during project execution. Many project managers identify and report on budget variances by comparing actual costs to planned costs (by reporting period), without taking into consideration planned vs. actual progress on the project. In this post I use an example from an actual project to help articulate the value of using earned value techniques to perform budget analysis.

Traditional Budget Analysis

The picture below depicts the labor related budget and actual costs from a project. This is the information created / captured during the planning (project budget information) and monthly budget update (actual cost information) processes.

If you are strictly comparing actuals to planned amounts, the budget performance looks fairly positive, and you would draw the following conclusions:

  • Tracking $6,153 under budget (Planned Costs to-date: $292,680 – Actual Costs to-date: $286,527)
  • $71,555 is the forecasted remaining costs to complete the project (Total Budget: $364,235 – Planned Costs to-date: $292,680)
  • $ 358,082 is the forecasted Estimate at completion of the project (Actual Costs to-date: $286,527 + Estimated to Complete: $71,555)

Even without completing the earned value calculation, you get an early indication of a potential schedule and/or cost related issue when you compare the total progress to-date from the project schedule (72%) to the total costs spent to-date (78.6%).

  • 78.6% of budget spent to-date (Actual Costs to-date: $286,527 / Total Project Budget: $364,235)
  • 80.3% is the planned completion % (Planned Value: $292,680 / Total Project Budget: $364,235)

Using Earned Value Techniques

If you progress the schedule on a regular basis, using a tool such as MS Project, you have all the information required to calculate earned value metrics. Start by organizing the information you need to calculate the key earned value metrics:

  • Planned value (PV) is the total amount budgeted through this time period (November 2010)
  • Earned value (EV) is calculated as the total budget * % Work Complete (from the project schedule)
  • Actual costs (AC) through November 2010
  • Cost Performance Index (CPI) = Earned Value / Actual Costs
  • SPI = Earned Value / Planned Value

In this case both the SPI and CPI are less than 1, which indicates that the project has a negative variance, both from a schedule and a cost perspective.

Upon completion of these calculations you are ready to calculate the key earned value metrics (estimated to complete, estimated at completion, and variance at completion):

  • Estimated to Complete (ETC) is $111,427 vs. $71,555 computed based upon planned vs. actual
  • Estimated At Completion (EAC) is $397,954 vs. $358,082 computed based upon planned vs. actual
  • Variance At Completion (VAC) is over budget ($33,719) vs. $6,153 under budget based upon planned vs. actual

Using the earned value technique for budget analysis, it becomes evident that the project is both over budget and behind schedule, and corrective action is most likely warranted. Integrating the work and time dimension in with the traditional budget and schedule analysis provides a whole different perspective on the project performance.

When to Use Earned Value

The example demonstrates the value associated with the earned value technique. The following points highlight a few considerations when determining the appropriate use of the earned value technique to measure project performance:

  • Good use of this technique requires that reliable schedule and cost data are available in a timely manner throughout the project life cycle:
    • Actual hours and costs are reported in an accurate and timely manner
    • Schedule progress (% complete) is updated regularly and is reasonably accurate
    • Planned % complete is available (either based upon budgeted hours or based upon the baseline established in the schedule)
  • Obviously budget control / management must be part of your role as the project manager to fully utilize the earned value technique. However, the same metrics can be derived by replacing costs with hours. The only thing that the earned value technique using hours will not highlight are rate related variances (since you are only using effort hours to drive the cost and schedule variances).
  • The earned value technique is most effective when there is a strong correlation between cost and the schedule. This is not an effective technique for example if 80% of the project cost is associated with a single purchase, and 80% of the project timing is associated with the implementation effort (which is only 20% of the cost).
  • The best metrics to utilize to track the cost and schedule performance trends are the CPI and SPI. These are fact based data points that are valuable to report to the project sponsors on a regular basis (as support of the rating of the overall health of the project).
  • The majority of this section (including the example) focuses on providing the analysis through the end of the project. However, if the cost and schedule information are organized properly, this analysis can be performed based upon major milestones (e.g., project phase). This practice would be best utilized for very large and complex projects involving several different large work efforts.
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