ISYS90050 · It Project and Change Management
Scheduling: WBS & Gantt Charts
Week 5 opens the scheduling block: why projects run late (Brooks' Mythical Man-Month and optimism bias), the basic scheduling principles, and how to decompose work into a Work Breakdown Structure (goal -> objective -> task -> activity) and represent it as a Gantt chart with milestones. The examinable edge is knowing the Gantt's limits — it hides task relationships — which motivates the network diagrams of the next chapter. WBS decomposition is examined in short answers and built in the group planning report.
What this chapter covers
- 01Why projects are late: Brooks' Mythical Man-Month, optimism bias; adding people to a late project makes it later
- 02Basic scheduling principles: compartmentalisation, interdependency, time allocation, effort validation, defined responsibilities/outcomes/milestones
- 03Work Breakdown Structure (WBS): hierarchical decomposition goal (0.0) -> objectives (1.0) -> tasks (1-1) -> activities (1-1-1)
- 04Estimate = forecast duration per activity based on the activity, resources and support
- 05Scheduling procedure: split into tasks, estimate, sequence concurrently, minimise dependencies, represent visually
- 06Gantt chart: bars on a time axis, diamonds = milestones, shaded = completed; tracks planned vs actual
- 07Gantt limitations: no explicit task relationships, hard for complex projects and multiple paths
- 08Milestone = one or more work products reviewed for quality and approved
Build a two-level WBS and read a Gantt limitation
- +1State the goal at 0.0 and decompose into objectives. 0.0 Deliver the user-training event; 1.0 Prepare logistics; 2.0 Prepare content. Objectives are the major outcomes, numbered at the first level.
- +1Break each objective into tasks with numeric codes. 1.0 Prepare logistics -> 1-1 Book the venue, 1-2 Arrange catering. 2.0 Prepare content -> 2-1 Write the training slides, 2-2 Prepare the hands-on exercises. Each task is a bite-sized unit that can be estimated and assigned.
- +1Read the Gantt limitation. A Gantt chart draws each task as a bar on a time axis but shows no explicit dependencies, so if "book the venue" (1-1) slips, the chart does not reveal that catering (1-2) and the whole event date depend on it — you cannot see the ripple of the delay, which is exactly what a network diagram exposes.
Key terms
- Work Breakdown Structure (WBS)
- A logical, hierarchical decomposition of the work into deliverables — goal (0.0) -> objectives (1.0) -> tasks (1-1) -> activities (1-1-1). It links scope to the plan and aids time estimates.
- Estimate
- A forecast duration for each activity, based on the activity itself, the assigned resources and the support available. Estimates feed the schedule and the Gantt/network representation.
- Gantt chart
- A bar chart of planned activities against a time axis that tracks planned versus actual progress; diamonds mark milestones and shading marks completed work. Its weakness is showing no explicit task relationships.
- Milestone
- A checkpoint tied to one or more work products that are reviewed for quality and approved. Milestones anchor the schedule and mark completion of a task or group of tasks.
- Effort validation
- A scheduling principle: never schedule more work than the available number of people can perform in the time — resources must match the plan.
- Brooks' Law
- The observation that adding people to a late software project tends to make it later (from The Mythical Man-Month), because of the extra communication and onboarding cost — a caution against fixing lateness by staffing up.
Scheduling: WBS & Gantt Charts FAQ
What is the difference between a WBS and a schedule?
A WBS decomposes the work by deliverable into a numbered hierarchy of objectives, tasks and activities — it says what must be done. A schedule adds durations, sequencing and dependencies to that work and lays it on a timeline (a Gantt or network diagram) — it says when. You build the WBS first, then estimate and sequence it.
Why is a Gantt chart not enough on its own?
A Gantt chart is excellent for showing progress against time, but its bars carry no explicit relationships, so it hides how tasks depend on each other. If one task slips you cannot see the ripple through dependent tasks or which path drives the finish date — that is why the course pairs it with network diagrams and the critical path.
Does adding people always speed up a late project?
No — a key exam point. Adding people to a late project often makes it later (Brooks' Law) because new members need onboarding and add communication overhead. The scheduling principle of effort validation says match the work to the people available rather than assuming more staff equals faster delivery.
Can AI help me with scheduling in ISYS90050?
Yes, as a study aid. Sia can walk you through decomposing a project into a numbered WBS, sequencing tasks, and explaining Gantt limitations. Use it to rehearse the method; it does not do your graded assignment, and University of Melbourne academic-integrity rules apply — confirm details on Canvas.
Exam move
Practise WBS decomposition on small projects until numbering (0.0 / 1.0 / 1-1) and drilling to bite-sized activities is second nature — you both answer this in short questions and build it in the group planning report. Learn the scheduling principles as a checklist and be ready to state the Gantt's central weakness (no explicit dependencies) because it is the hinge into the critical-path chapter. Keep Brooks' Law and effort validation ready for a "why do projects run late" prompt. Since the exam is closed-book, rehearse producing a clean WBS from a plain scenario under time pressure.
Working through Scheduling: WBS & Gantt Charts in ISYS90050? Sia is AskSia’s AI IT Project Management tutor — ask any ISYS90050 Scheduling: WBS & Gantt Charts question and get a clear, step-by-step explanation grounded in how ISYS90050 is taught and assessed. Read this chapter free, then take your hardest questions to Sia.
