A Product Breakdown Structure (PBS) is a fundamental planning technique within PRINCE2 7 that provides a hierarchical decomposition of the final project deliverable into its constituent parts and sub-products. It serves as a cornerstone of product-based planning, which is central to the Plans pract…A Product Breakdown Structure (PBS) is a fundamental planning technique within PRINCE2 7 that provides a hierarchical decomposition of the final project deliverable into its constituent parts and sub-products. It serves as a cornerstone of product-based planning, which is central to the Plans practice in PRINCE2.
The PBS starts with the overall project product at the top level and progressively breaks it down into smaller, more manageable components. Each level of decomposition reveals greater detail about what needs to be produced. This hierarchical structure resembles a family tree, showing the relationship between the main product and all its component parts.
The primary purpose of a PBS is to ensure comprehensive identification of all products required to complete the project successfully. By visualising the complete scope of work in terms of deliverables, project teams can better understand what needs to be created and avoid overlooking essential components.
Key benefits of using a PBS include improved clarity regarding project scope, enhanced communication among stakeholders, and a solid foundation for developing other planning elements such as Product Descriptions and the Product Flow Diagram. It helps teams think systematically about deliverables rather than focusing solely on activities.
When constructing a PBS, products are typically categorised as either internal products (created by the project team) or external products (sourced from outside the project but still required for project completion). This distinction helps in resource planning and procurement considerations.
The PBS feeds into subsequent planning steps where Product Descriptions are written for each identified product, defining quality criteria, composition, and other essential characteristics. Following this, dependencies between products are mapped through a Product Flow Diagram, which ultimately informs activity planning and scheduling. The PBS therefore represents an essential first step in the product-based planning approach that PRINCE2 advocates for effective project management.
A Product Breakdown Structure (PBS) is a hierarchical diagram that breaks down the final project product into its component parts. It provides a visual representation of all the products that need to be created during a project, organized in a tree structure format.
The PBS starts with the overall project product at the top and progressively breaks it down into smaller, more manageable sub-products. Each level provides more detail than the one above it.
Why is the PBS Important?
The Product Breakdown Structure is crucial for several reasons:
• Clarity of scope: It clearly defines what needs to be delivered, helping prevent scope creep • Foundation for planning: It forms the basis for creating product descriptions and the product flow diagram • Communication tool: It provides a simple visual that all stakeholders can understand • Identifies dependencies: Helps reveal relationships between products • Supports estimation: Breaking products down makes it easier to estimate effort, time, and resources • Quality planning: Each identified product can have quality criteria defined
How Does the PBS Work?
The PBS follows a simple hierarchical structure:
Level 1: The final project product (what the project will ultimately deliver) Level 2: Major component products that make up the final product Level 3: Sub-components of the Level 2 products And so on...
The PBS includes three types of products:
• Specialist products: Products specific to the project that fulfill the customer requirements • Management products: Products required to manage the project (plans, reports, logs) • External products: Products not created by the project but needed as inputs
Creating a PBS - Step by Step
1. Identify the final project product 2. Break this down into its major components 3. Continue breaking down each component until you reach a manageable level of detail 4. Include external products that are needed 5. Review to ensure completeness
Relationship to Other Planning Tools
The PBS is the first of three planning tools used in sequence:
1. Product Breakdown Structure (PBS) - identifies WHAT needs to be produced 2. Product Description - describes each product in detail 3. Product Flow Diagram (PFD) - shows the sequence and dependencies
These tools together form the foundation of product-based planning in PRINCE2.
Exam Tips: Answering Questions on Product Breakdown Structure
• Remember the purpose: The PBS identifies and breaks down products - it does NOT show sequence or timing
• Know the difference: PBS shows the hierarchy of products; the Product Flow Diagram shows the order of creation
• Three product types: Be able to distinguish between specialist, management, and external products
• Hierarchical structure: The PBS is always shown as a tree diagram with the final product at the top
• Part of product-based planning: Questions may ask which technique the PBS belongs to - it is a key element of product-based planning
• Plans practice: The PBS is created during the Plans practice activities
• Watch for distractors: If an answer mentions showing duration, resources, or dependencies with timing - this is NOT what a PBS does
• Key phrase to remember: The PBS provides a complete picture of the products to be delivered
• Level of detail: The PBS should be broken down to a level where products can be meaningfully described and planned