Compare the actual amount of time used or money expended to the
planned amount (e.g., the plan was that the project would require
80 hours and we have used 40 hours so we have completed 50%
of the project)
Shortcomings of this Approach:
The planned amount (whether measured in time or money)
may have been overestimated or underestimated
The planned drawdown rate may not have been linear over time
(so, just because we have spent 50% of the budget may not mean
that the project is 50% complete, even if the original estimate
was correct)
A Better Approach - Earned Value Analysis
The Concept:
Use a quantifiable measure of progress (called the
value)
Compare the planned value with the
earned value over time
The Process:
Before the project starts, use the project plan to
calculate the planned value for each
period, \(V_t^*\)
While the project is underway, calculate the
actual value for each period, \(V_t\)
Earned Value Analysis (cont.)
Dollar-Based Measures of Value:
The monetary business value of the features
Feature-Based Measures of Value:
The normalized number of features (sometimes called
story points)
Earned Value Analysis (cont.)
Metrics
Schedule-Related Metrics:
Schedule Variance (in Value Units):
\(\sum_{t=1}^{T} V_t - \sum_{t=1}^{T} V_t^*\)
Schedule Variance (in Time Units):
The difference between the time a particular value was
completed and the time that value was planned to be
completed (positive when ahead, negative when behind)
Cost-Related Metrics:
Cost Variance:
\(\sum_{t=1}^{T} V_t - \sum_{t=1}^{T} C_t\)
where \(V_t\) is measured in dollars and
\(C_t\) denotes the costs incurred during period
\(t\)