Schedule Updating and Project Control - Construction Project Scheduling and Control - page 201

Figure 7.18 Schedule performance versus budget performance: quadrant I, ahead of
schedule and under budget; quadrant II, behind schedule and under budget; quadrant III,
behind schedule and over budget; quadrant IV, ahead of schedule but over budget

taken a larger-than-expected percentage. This causes major concern, especially
in fixed-price contracts.
3. A large positive variance may not be a reason for celebration. It may indicate
an error or an overestimation in the baseline budget and/or schedule.
4. Schedule performance and budget performance are independent of each other.
The contractor may find that he or she is operating under the conditions found
in one of the four quadrants shown in Figure 7.18. Quadrant I means the
project is ahead of schedule and under budget (where you want to be). Quad-
rant II gives you bad news (you are behind schedule) and good news (and
under budget). Quadrant III is the worst: you are behind schedule and over
budget. Quadrant IV is the opposite of quadrant II: you are ahead of schedule
but over budget.

Another parameter that was suggested is the cost-schedule index (CSI), which is
the product of the cost performance index (CPI) and the schedule performance index
(SPI). The main problem with this parameter is the possibility that good performance
in one area masks substandard performance in the other. For example, in our previous
sample project, the CSI was 0

. 94 ∗ 1 . 20 = 1 . 13, which is good but misleading.

Tip Box 7.10

Earned value can be a valuable tool; however, it is a tool that may or may not be the
most suitable for the situation.