Project Schedule Management
Domain 5 covers the six scheduling processes, with heavy emphasis on dependency logic, three-point estimation, critical path calculation, float, and schedule compression. Expect at least one network-diagram calculation and one question distinguishing resource levelling from resource smoothing.
Building the schedule
- Sequence activities with the precedence diagramming method. Four logical relationships: finish-to-start, start-to-start, finish-to-finish, start-to-finish.
- Dependencies are mandatory or discretionary, internal or external. Leads and lags adjust them.
- Duration estimating tools: analogous, parametric, bottom-up, three-point, and reserve analysis.
- PERT beta estimate = (O + 4M + P) / 6; standard deviation = (P − O) / 6; triangular estimate = (O + M + P) / 3.
Critical path and float
- The critical path is the longest path through the network and determines the shortest possible duration. It has zero total float and there may be more than one.
- Total float = LS − ES = LF − EF. Free float = earliest start of the successor − early finish of the activity.
- A negative total float means the imposed finish date is infeasible and the schedule must be compressed.
- Resource levelling may extend the critical path; resource smoothing keeps the critical path and dates unchanged by using float only.
- Compression: crashing adds resources or overtime and raises cost; fast tracking overlaps activities and raises risk and rework.
Control
Performance reviews, earned value schedule indicators, burn-down charts, variance analysis, what-if simulation such as Monte Carlo, and schedule baseline change control.
Worked example
Network: A(3) precedes B(4) and C(6); both precede D(5). Path A-B-D = 12 days; path A-C-D = 14 days. The critical path is A-C-D at 14 days. For B: early start 3, early finish 7, and its successor D cannot start until 9, so late finish 9 and total float 2 days. Crashing B would not shorten the project; only A, C, or D can.
Traps that cost marks
- Crashing a non-critical activity and claiming the project finishes earlier.
- Saying resource smoothing may change the critical path; it does not.
- Confusing free float with total float.
- Assuming fast tracking increases cost; it mainly increases risk.
- Forgetting that the critical path can change after compression.