Project Work Planning
What you must know
Work planning is where scope becomes a schedule and a budget. Candidates must know the work breakdown structure (WBS), task dependencies, critical path method (CPM), float/slack, and milestones. Understand deliverables vs. activities, and how the AIA B101-style phases (schematic design through construction administration) map to percent-complete billing. Know earned value basics: PV, EV, AC, and CPI/SPI.
Traps in questions
- Confusing critical path (longest path, zero float) with the most expensive or most staffed path.
- Forgetting that float belongs to the activity, and consuming it early can make a later task critical.
- Mixing percent complete by cost with percent complete by time.
- Assuming a lag or lead changes logic when it only shifts timing.
- Treating a milestone as work - it has zero duration.
Worked rule of thumb
Critical path: list paths and sum durations; the longest total is critical. If Path A = 12 days, Path B = 9 days, Path C = 14 days, then C is critical and A has 2 days of float. On earned value, if PV = $50k, EV = $40k, AC = $45k, then CPI = EV/AC = 0.89 (over cost) and SPI = EV/PV = 0.80 (behind schedule). Report both - a project can be on schedule but over budget.
Key habit: always draw the network and total each path before answering duration or float questions.