ProjectFlightDeck

Concept: Earned Schedule is the time on a project at which the value currently earned should have been earned.  (See Chart 1)  To calculate the amount of Earned Schedule, compare the Earned Value (BCWP) at the actual time to the Planned Value (BCWS) at the end of each time period in the schedule. Count the number of time periods in which the Earned Value is greater than or equal to the Planned Value. Add in any fractional amount.

Chart 1

The ES metric can be used to manage schedule performance. The Schedule Burndown Chart shows whether or not time is being used according to the original plan. The original (i.e., baseline) plan may or may not coincide with the current schedule.

Chart 2

Practice:  The ES metric has many advantages, but it also has some limitations.

Pro:

• Easy to produce. Assuming that you are already using Earned Value Management, you have all the data you need to generate the ES metric.
• Easy to understand. If the ES Burndown line is over the Expected line, not as much schedule has been earned as expected, i.e., the project is late. If the ES Burndown line is under the Expected line, more time has been earned than expected, i.e., the project is early. The size of the gap suggests the seriousness of the difference.
• Easy to communicate. Because the ES metric can be represented in a graph, it avoids linguistic and cultural barriers. It also  applies both to plan-driven projects and to ones that are more Agile, providing a common “language” to describe schedule performance.
• Easy to introduce. The ES metric is a good first step for introducing Earned Schedule into an organization. It is quick to implement, fits with existing practices, and adds information valuable for managing schedule performance.

Con:

• Hard to gauge. The ES metric is an absolute measure, expressed in units of time. Consequently, it is difficult to assess how serious a gap is: for example, a one-month gap early in a large, multi-year program does not have the same seriousness as a one-month gap late in a small, six-month project. Put simply, the ES metric expresses whether or not time is being earned according to plan, not how well or how poorly schedule is being earned. For that, other ES metrics, such as the SPIt and TSPI, are better indicators.
• Hard to predict. The ES metric itself does not predict future performance. While the slope of the lines and size of the gap suggest how the project will perform in the future, they do so based on impression and experience, rather than on quantitative analysis. Again, other ES metrics, such as the EACt and statistical analysis, are better predictors of future performance.

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Concept: Earned Schedule is the time on a project at which the value currently earned should have been earned.  (See Chart 1)  To calculate the amount of Earned Schedule, compare the Earned Value (BCWP) at the actual time to the Planned Value (BCWS) at the end of each time period in the schedule. Count the number of time periods in which the Earned Value is greater than or equal to the Planned Value. Add in any fractional amount.

Chart 1

The ES metric can be expressed in a Schedule Burndown Chart. It shows whether or not time is being used according to the original plan. The original (i.e., baseline) plan may or may not coincide with the current schedule.

Chart 2

Practice:There are seven steps for using the ES metric’s Burndown Chart to manage schedule performance.

Step 1. Set the scales on the Burndown chart to planned maximums. Initially, place the total number of planned periods on the vertical axis, and put the end date of the final planned period on the horizontal axis.

Step 2. Assign the starting point for the Expected Burndown and the Earned Schedule Burndown. Both start at the maximum number of planned periods.

Step 3. Modify the scales as required. Later in a project, it often becomes necessary to add time to the schedule. Assuming that a new baseline is not required, more periods are simply added to the maximum number of periods on the vertical axis, and the horizontal axis is extended to accommodate the end date of the final scheduled period.

Step 4. Modify the end points as required. The end point of the Expected Burndown remains the end date of the final planned period. The end point of the Earned Schedule Burndown, however, becomes the end date of the final scheduled period. The start points are not adjusted.

Although it is not common, an early finish is also possible. In such a case, the Expected Burndown operates the same way as for late projects. On the vertical axis, the start point and the maximum number of periods remain the total number of planned periods. On the horizontal axis, the final planned period’s end date stays in place. The Expected Burndown, however, finishes at an earlier period.

Step 5. Use the ES metric to assess schedule performance. If the ES is less than the actual time, the project is late. If the ES is greater than the actual time, the project is early. The Burndown Chart depicts it this way: if the ES line is over the Expected line, the project is taking longer than it should to accumulate Earned Schedule. In short, the project is late.
If the ES line is under the Expected line, the project is accumulating Earned Schedule faster than planned. It is early.

Step 6. Evaluate the results. Any deviation from a well-conceived plan is a concern. If a project team earns value earlier than planned, it is often viewed as a positive accomplishment, but that is not always the case. The plan may have been based on a low-ball estimate, and the project team is actually capable of higher productivity than planned. The plan may need to be revised.

On the other hand, not all deviations indicate serious problems—there is a natural variability in any project. Responses to deviations, therefore, must depend on the size, cadence, and direction of deviations. A widening gap, such as the one in Chart 2, indicates that the problem is worsening. If a gap continues to grow over two or three periods, it demands attention. For the project in which Chart 2 was created, we responded to the gap by period 6—that’s two periods after a gap first appeared.

Step 7. Remediate the schedule as required. Once a problem is recognized, do root cause analysis. You need to uncover the reason(s) for the deviation. Based on the analysis, form and implement an action plan that addresses the underlying cause(s). The action plan will vary, depending on the reason for the gap. Follow up continues until the gap closes.

Concept: Earned Schedule is the time on a project at which the value currently earned should have been earned.  See Chart 1 and Lipke (2003). To calculate the amount of Earned Schedule, compare the Earned Value (BCWP) at the current time to the Planned Value (BCWS) at the end of each time period in the schedule. Count the number of time periods in which the Earned Value is greater than or equal to the Planned Value. Add in any fractional amount.*

Chart 1

Practice: The Earned Schedule metric (ES) is the basis for an array of associated metrics (SPIt, EACt, TSPI, P Factor, and others). Beyond that, ES is a useful measure in its own right. Here’s how to apply it in practice.

Assuming a well-formed plan, the value earned on a project is expected to track the value planned for the project. That is, for each time period spent, an equivalent amount of time should be earned.

Earned Schedule quantifies how much time is actually earned for the time spent. When compared to the expected track, the ES metric shows how well or poorly time is being used relative to the expected utilization.

To borrow a practice from the Agile framework, we can depict the utilization using a Burndown Chart. See Saddington (2013). Let’s call our version the Schedule Burndown. (See Chart 2.)

Chart 2

In the Schedule Burndown Chart, the vertical scale represents the total number of periods remaining in the project. The horizontal scale represents the end date of each period.

The Expected Burndown line represents the expected track for time utilization, running straight from the first period to the last planned period. The ES Burndown line shows how much time has actually been earned, extending from the first period to the last scheduled period.  To get the ES Burndown, you decrement the planned total by the amount of schedule that is earned in each period.

If the ES Burndown line is above the Expected Burndown line, the project is late. If the ES Burndown line is below the Expected Burndown line, the project is early.

If the project is late, the total number of periods will grow greater than the number of planned periods. Hence, in Chart 2, both Burndown lines start at period 8, rather than period 10. To finish, two periods were added to the schedule beyond the ones in the baseline.

Similarly, the Expected Burndown line finished two periods before the end, reflecting the fact that it took 10 periods to earn 8 periods.

The ES Burndown Chart is easy to create and to understand. It is especially useful as a communication tool and as a first-step in your Earned Schedule practice.

Notes
*To find the fractional amount, divide the amount of value earned in the fractional period alone by the total amount of value planned for the same period.

References
Lipke, W. (2003). Schedule is Different. The Measurable News, Summer.
Saddington, P. (2013). The Agile Pocket Guide. Hoboken, New Jersey: Wiley.