Product Breakdown Structure (PBS) vs. Work Breakdown Structure (WBS)

Focus:

• PBS: Tangible outputs of the project (products, deliverables)
• WBS: Work required to produce those outputs (tasks, activities)

Structure:

• PBS: Hierarchical decomposition of products into components
• WBS: Hierarchical decomposition of work into smaller tasks

Key Differences:

• PBS: Helps define the scope of the project in terms of deliverables.
• WBS: Guides project planning and execution.

Relationship:

• PBS often informs the development of the WBS, ensuring the work aligns with the desired outputs.

Image:

Scope Baseline

Definition:

• A set of documents that define the project’s scope and serve as a reference point for managing scope changes.

Components:

• Scope Statement: A detailed description of the project’s scope.
• WBS: A hierarchical decomposition of the work required to deliver the project scope.
• WBS Dictionary: Detailed descriptions of each WBS element.

Importance:

• Establishes a clear understanding of the project’s scope among stakeholders.
• Provides a basis for measuring progress and managing scope change.
• Helps prevent scope creep, which can lead to project delays and cost overruns.

Cone of Uncertainty vs. Rolling Wave Planning

Cone of Uncertainty:

• A concept illustrating the decreasing level of uncertainty in project estimates as the project progresses.
• Early in the project, estimates have a wide range of potential outcomes.
• As the project progresses, more information becomes available, and estimates become more accurate.

Rolling Wave Planning:

• An iterative planning approach that focuses on near-term work while allowing for flexibility in the future.
• Detailed planning is done for the immediate work, while high-level planning is done for future work.
• Plans are updated regularly as new information becomes available.

Similarities:

• Both acknowledge the uncertainty inherent in project planning.
• Both emphasize the need for adaptability and flexibility in planning.

Differences:

• Cone of Uncertainty focuses on the concept of uncertainty itself.
• Rolling Wave Planning is a specific planning technique that addresses uncertainty.

Image:

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cone, representing the Cone of Uncertainty, with the level of uncertainty decreasing as the project progresses

Constraints on Activity Sequencing

Types of Constraints:

• Mandatory Dependencies: Hard constraints that must be followed (e.g., foundation must be laid before building walls).
• Discretionary Dependencies: Preferred sequences based on best practices or experience (e.g., testing after coding).
• External Dependencies: Constraints imposed by external factors (e.g., waiting for a government permit).
• Resource Constraints: Limitations on resources like staff, equipment, or budget.

Examples:

• Mandatory Dependency: Painting a room cannot start until the walls are dry.
• Discretionary Dependency: Hiring a project manager is often done early in the project.
• External Dependency: Obtaining a permit from the city is required before starting construction.
• Resource Constraint: A limited number of developers may restrict the number of tasks that can be worked on simultaneously.