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AALL1003 Project planning and scheduling

Project classifications and life cycle

  • Projects may be classified by size, sector, urgency, funding source, complexity, or public/private character.
  • A project is temporary, goal-oriented, resource-bounded work.
  • Common life-cycle phases are initiation, planning, execution, monitoring and controlling, and closing.

Project planning process

Typical planning steps:

  1. Define objectives and scope.
  2. Break work into tasks or work packages.
  3. Estimate time, cost, and resources.
  4. Sequence activities and dependencies.
  5. Prepare schedule and budget.
  6. Assign responsibilities.

  7. Plan risk, quality, communication, and control.

  8. Scope clarity comes before detailed scheduling.

  9. A weak work breakdown usually causes weak schedule control.

Bar chart or Gantt chart

  • A bar chart shows activities against time.
  • It is easy to read and communicate.
  • It is weaker than network methods for dependency and critical-path analysis.

CPM

  • Critical Path Method uses deterministic activity durations.
  • The critical path is the longest-duration path through the network.
  • Activities on the critical path have zero total float under the usual baseline assumptions.
  • Delaying a critical activity delays the whole project unless corrective action is taken.

Float relation:

\[ \text{Total Float} = LS - ES = LF - EF \]

PERT

  • Program Evaluation and Review Technique uses probabilistic time estimates.
  • PERT activity expected duration:
\[ t_e = \frac{a + 4m + b}{6} \]
  • \(a\): optimistic time.
  • \(m\): most likely time.
  • \(b\): pessimistic time.

PERT variance:

\[ \sigma^2 = \left(\frac{b-a}{6}\right)^2 \]
  • PERT is useful when durations are uncertain.

CPM versus PERT

Aspect CPM PERT
Time estimate Deterministic Probabilistic
Main emphasis Cost-time tradeoff and control Schedule uncertainty
Typical use Repetitive or well-known activities R&D or uncertain work

Resource levelling versus smoothing

Method Main goal Effect on project finish
Resource levelling Resolve over-allocation when resources are limited May change finish date
Resource smoothing Even out resource usage within float limits Usually keeps finish date unchanged
  • This distinction is a favorite conceptual MCQ.

Monitoring, evaluation, and controlling

  • Monitoring tracks actual progress and data collection.
  • Evaluation judges performance and results against objectives.
  • Controlling takes corrective action when variance appears.
  • Baseline schedule, cost, scope, and quality targets are the comparison points.

Recognition cues for project management

  • "Longest path through network" means critical path.
  • "Optimistic, most likely, pessimistic" means PERT.
  • "Redistribute resources without changing finish date if possible" means smoothing.
  • "Adjust schedule because resources are limited" means levelling.

Common traps in project management

  • Critical path is not always the path with the most activities; it is the path with maximum duration.
  • Zero float indicates schedule sensitivity.
  • PERT expected time is weighted toward the most likely estimate, not a simple average.
  • Resource levelling and smoothing are not synonyms.

One-step examples for project management

  • If \(a=2\), \(m=5\), and \(b=8\), then \(t_e=(2+20+8)/6 = 5\).
  • If an activity has ES 4 and LS 7, total float is 3.
  • If a noncritical activity slips within its float, project finish may remain unchanged.

Project-management revision box

CPM is deterministic; PERT is probabilistic. Critical path controls project duration. PERT uses \(t_e=(a+4m+b)/6\). Resource levelling may shift the finish date; smoothing aims to stay within the original date by using available float.