Predictive, Plan-Based Methodologies
What this domain tests
Predictive (waterfall) delivery assumes requirements are knowable up front and change is controlled through formal approval. Candidates must know the process groups (initiating, planning, executing, monitoring and controlling, closing) and the knowledge areas that organize them, plus how scope, schedule, and cost baselines are built and controlled.
Concepts to master
- Scope baseline = scope statement + WBS + WBS dictionary. The WBS decomposes deliverables; work packages sit at the bottom.
- Critical path method: the longest path through the network determines minimum duration. Float (slack) is the amount a task can slip without delaying the project; critical-path tasks have zero float.
- Earned value management: PV (planned value), EV (earned value), AC (actual cost). CV = EV − AC; SV = EV − PV; CPI = EV/AC; SPI = EV/PV. Cost and schedule variances are in currency; indices are ratios.
- Change control: any change to a baselined item goes through a change request, impact analysis, and approval before implementation.
- Quality vs. grade, and preventive vs. corrective action.
Traps in questions
A negative SV does not mean the project is over budget - that is CV. A CPI above 1.0 means under budget. Questions often tempt you to “just update the plan” after a change; the correct answer is to submit the change request first. Also watch for confusing validate scope (customer accepts deliverables) with control quality (inspect for correctness).
Worked example
A task has PV = 400, EV = 350, AC = 380. CV = 350 − 380 = −30 (over budget). SV = 350 − 400 = −50 (behind schedule). CPI = 350/380 ≈ 0.92. The project is both over budget and behind schedule.