Schedule and Cost Management
Schedule and Cost Management
This domain tests activity sequencing, critical path and float, schedule compression, cost baselines, and earned value management. Expect calculations plus judgment about what the numbers mean.
Core rules
- The critical path is the longest path through the network and has the least total float, usually zero. A delay on the critical path delays the project unless the path changes.
- Crashing adds resources and usually cost. Fast tracking overlaps activities and usually adds risk. Neither is free.
- Earned value formulas: CV = EV − AC; SV = EV − PV; CPI = EV/AC; SPI = EV/PV. EAC = BAC/CPI only when current cost performance is expected to continue.
- Cost baseline excludes management reserve; the project budget includes it. Contingency reserve is for identified risks.
Worked example
BAC = $200,000; PV = $80,000; EV = $70,000; AC = $90,000. CV = 70,000 − 90,000 = −$20,000 (over budget). SV = 70,000 − 80,000 = −$10,000 (behind schedule). CPI = 0.78; SPI = 0.88. If current performance continues, EAC = 200,000 / 0.78 ≈ $257,000. Reasoning: the project has earned less value than planned and spent more than earned, so both cost and schedule need corrective analysis.
Traps that cost marks
- Using SPI as a reliable schedule indicator without checking the critical path.
- Applying BAC/CPI when the variance is known to be one-time or atypical.
- Confusing percent complete with earned value.
- Treating sunk cost as a reason to continue a failing project.