Many project managers look to Earned Value Management (EVM) values to predict whether or not their project will complete on time and on budget. Recently, the Defense Contract Management Agency (DCMA) 14-point assessment’s Baseline Execution Index (BEI) has been popularized as a schedule completion early warning metric.
One of the project manager’s major duties is to monitor schedule progress and make appropriate schedule adjustments to keep the project on schedule. The Schedule Performance Index (SPI) is an earned value management metric that helps project managers extrapolate their project’s schedule completion situation. The SPI metric divides Earned Value (EV) by Planned Value (PV) to determine how close the earned value is to what was planned at this particular point in the project lifecycle. The ideal being, of course, 1 or greater, less than 1 is unfavorable. The SPI thus provides the project manager keen insight into the progress of the schedule.
Recent studies, however, have indicated that the Baseline Execution Index provides an earlier schedule completion warning metric. The BEI is like the canary in the mine, providing first warning alert that something is amiss.
This article introduces the Baseline Execution Index as a useful schedule completion early warning metric.
Before calculating BEI we want to make sure we understand the formula. DCMA defines the BEI ratio as follows:
BEIcum = (Total # of Tasks Complete) / (Total # of Tasks Completed Before Now+Total # of Tasks Missing Baseline Finish Date)
The denominator nomenclature is cause for confusion. The following equivalence helps to better understand the denominator:
Total # of Tasks Completed Before Now + Total # of Incomplete Tasks Missing Baseline Finish Date = Total # Activities that should be complete
Note the denominator is the sum of completed tasks and incomplete tasks missing a baseline finish date. This is equivalent to total # activities that should be complete. The BEI formula, therefore, simplifies to the following:
BEIcum = (Total # of Tasks Complete) / (Total # of Tasks that Should be Complete)
The DCMA wants us to consider the denominator as a baseline count equivalent to the number of tasks with a baseline finish date on or before the status date. The BEI equation becomes:
BEIcum = (Total # of Tasks Complete) / (Baseline Count)
Where, again
Baseline Count = Total # of Tasks with Baseline Finish Date on or Before the Status Date
So the BEI ratio nomenclature is confusing but the formula comes down to two terms: total # of tasks complete and total # of tasks that should be complete (or the baseline count). This formula only applies to normal tasks, so we filter out LOE, summary tasks, and zero duration tasks (milestones).
A BEI greater than 1 is good and a BEI of less than 1 is not so good. If tasks are not completing by the status date as scheduled, then something is wrong with the schedule. The BEI is a means of measuring task completion issues relative to the status date. If tasks’ completion, as per the data date, is insufficient a BEI < 1 warns the project manager that the schedule is heading off course and needs attention.
The BEI provides a warning indication that your schedule is veering towards trouble. Note, as an example, a schedule that has 1 task incomplete out of 20 that should be complete by the status date. The BEI computes as follows:
BEI = 19/(19+1) = 19/20=0.95
So this schedule passes the BEI test, which specifies that BEI’s 0.95 and above are passing.
Let’s consider the DCMA 14-points point-11 missed tasks assessment. The same schedule will compute a % missed task value as follows:
% Missed Tasks = (# of Tasks with Actual or Forecast Finish Date Past Baseline Date) / (# of Tasks with Baseline Finish Date on or Before Status Date) x100
% Missed Task = 1/20 × 100 = 5%
It passes the % missed task test that says no more than 5% of schedule incomplete tasks should have missed baseline finish dates. But what if two tasks missed their baseline finish dates, but only one remains incomplete by the status date? In this situation the BEI remains 0.95, but the % missed task ratio computes as follows:
% Missed Task = 2/20 × 100 = 10%
So the missed tasks formula numerator includes tasks that missed their baseline finish, but are, none-the-less, complete. The missed task ratio thus includes minutiae that makes the schedule fail the missed task pass/fail criteria. Is it really a better gage of progress to include or flag completed tasks simply because they missed their baseline finish date?
The Baseline Execution Index simplifies the equation to what’s complete by the status date divided by what should be complete by the status date. It’s fine for an activity to miss its baseline finish date as long as it is complete by the status date. So the BEI avoids trivial schedule lapses, but provides an objective and sensitive measurement of schedule progress.
It is unfortunate that neither Primavera P6 Professional nor Microsoft Project have BEI variables. Primavera P6 Enterprise Project Portfolio Management (P6 EPPM), however, does include a BEI metric in its schedule check feature. Let’s demonstrate a BEI computation in Primavera P6 Professional and below, in Figure 1, is our demonstration schedule.
Figure 1
This schedule has progressed 2 months: January and February. The number of tasks with actual finish dates is computed using the following filter, Figure 2:
Figure 2
Applying this filter we find that ten tasks have an actual finish dates before the status date, Figure 3.
Figure 3
The number of tasks scheduled to finish prior to status date computes with the following filter, Figure 4.
Figure 4
Eleven tasks were scheduled to complete before the status date, Figure 5.
Figure 5
The BEI computes as follows:
BEI = 10 / (10+1) = 10/11 = 0.91
So this schedule fails the Baseline Execution Index criteria. Our schedule requires further attention. This may be a good time to further inspect the schedule, in particular, its SPI (EV/PV).
Summary
A project manager’s major duty is to monitor schedule progress, and make adjustments to keep the project on time. The earlier a project manager can spot and judiciously diagnose a schedule diverting from the plan the better.
Recent studies indicate that the BEI provides an objective (nontrivial) but sensitive early warning detection for schedules in danger of missing their deadline. The missed task assessment, on the other hand, maybe too sensitive to minor schedule lapses.
A variable for BEI does not exist in Primavera P6 Professional nor Microsoft Project. Schedulers may have to rely on output variables and filters to determine both the numerator and denominator in the BEI ratio. Still the early warning the BEI ratio provides, when a schedule is becoming unhinged, may be well worth the effort required to compute its value. Again, Baseline Execution Index among progress ratios is both judicious and reasonably sensitive; it provides a clear and definite warning signal when something in the schedule is amiss.