Work breakdown structure

Editor's Notes

• #9: 100% ruleAn important design principle for work breakdown structures is called the 100% rule. It has been defined as follows:The 100% rule states that the WBS includes 100% of the work defined by the project scope and captures all deliverables – internal, external, interim – in terms of the work to be completed, including project management. The 100% rule is one of the most important principles guiding the development, decomposition and evaluation of the WBS. The rule applies at all levels within the hierarchy: the sum of the work at the “child” level must equal 100% of the work represented by the “parent” and the WBS should not include any work that falls outside the actual scope of the project, that is, it cannot include more than 100% of the work… It is important to remember that the 100% rule also applies to the activity level. The work represented by the activities in each work package must add up to 100% of the work necessary to complete the work package.Mutually exclusive elementsIn addition to the 100% rule, it is important that there is no overlap in scope definition between two elements of a work breakdown structure. This ambiguity could result in duplicated work or mis-communications about responsibility and authority. Such overlap could also cause confusion regarding project cost accounting. If the WBS element names are ambiguous, a WBS dictionary can help clarify the distinctions between WBS elements. The WBS Dictionary describes each component of the WBS with milestones, deliverables, activities, scope, and sometimes dates, resources, costs, quality.Plan outcomes, not actionsIf the work breakdown structure designer attempts to capture any action-oriented details in the WBS, s/he will likely include either too many actions or too few actions. Too many actions will exceed 100% of the parent's scope and too few will fall short of 100% of the parent's scope. It is consideredthat the best way to adhere to the 100% rule is to define WBS elements in terms of outcomes or results. This also ensures that the WBS is not overly prescriptive of methods, allowing for greater ingenuity and creative thinking on the part of the project participants. For new product development projects, the most common technique to ensure an outcome-oriented WBS is to use a product breakdown structure. Feature-driven software projects may use a similar technique which is to employ a feature breakdown structure. When a project provides professional services, a common technique is to capture all planned deliverables to create a deliverable-oriented WBS. Work breakdown structures that subdivide work by project phases (e.g. preliminary design phase, critical design phase) must ensure that phases are clearly separated by a deliverable also used in defining entry and exit criteria (e.g. an approved preliminary or critical design review).Level of detailOne must decide when to stop dividing work into smaller elements. This will assist in determining the duration of activities necessary to produce a deliverable defined by the WBS. There are several heuristics or "rules of thumb" used when determining the appropriate duration of an activity or group of activities necessary to produce a specific deliverable defined by the WBS.The first is the "80 hour rule" which means that no single activity or group of activities to produce a single deliverable should be more than 80 hours of effort.The second rule of thumb is that no activity or series of activities should be longer than a single reporting period. Thus if the project team is reporting progress monthly, then no single activity or series of activities should be longer than one month long.The last heuristic is the "if it makes sense" rule. Applying this rule of thumb, one can apply "common sense" when creating the duration of a single activity or group of activities necessary to produce a deliverable defined by the WBS.A work package at the activity level is a task that:can be realistically and confidently estimated;makes no sense practically to break down any further;can be completed in accordance with one of the heuristics defined above;produces a deliverable which is measurable; andforms a unique package of work which can be outsourced or contracted out.Coding schemeIt is common for work breakdown structure elements to be numbered sequentially to reveal the hierarchical structure. The purpose for the numbering is to provide a consistent approach to identifying and managing the WBS across like systems regardless of vendor or service.For example 1.1.2 Propulsion (in the example below) identifies this item as a Level 3 WBS element, since there are three numbers separated by a decimal point. A coding scheme also helps WBS elements to be recognized in any written context.A practical example of the WBS coding scheme is1.0 Aircraft System1.1 Air Vehicle1.1.1 Airframe 1.1.1.1 Airframe Integration, Assembly, Test and Checkout 1.1.1.2 Fuselage 1.1.1.3 Wing 1.1.1.4 Empennage 1.1.1.5 Nacelle 1.1.1.6 Other Airframe Components 1..n (Specify) 1.1.2 Propulsion 1.1.3 Vehicle Subsystems 1.1.4 Avionics1.2 System Engineering1.3 Program Management1.4 System Test and Evaluation1.5 Training1.6 Data1.7 Peculiar Support Equipment1.8 Common Support Equipment1.9 Operational/Site Activation1.10 Industrial Facilities1.11 Initial Spares and Repair PartsAn example in the software industry would be as follows:1267.1 Systems Integration 1267.1.1 Requirements Definition 1267.1.2 Regulations 1267.1.3 Scheduling 1267.1.4 Monitoring & Control 1267.1.5 Procurement Management 1267.1.6 Closeout1267.2 Design 1267.2.1 Conceptual Design 1267.2.2 Preliminary Design 1267.2.3 Final DesignTerminal elementA terminal element is the lowest element (activity or deliverable) in a work breakdown structure; it is not further subdivided. Terminal elements are the items that are estimated in terms of resource requirements, budget and duration; linked by dependencies; and scheduled. At the juncture of the WBS element and organization unit, control accounts and work packages are established and performance is planned, measured, recorded, and controlled.
• #10: Vague: Not clear ( Cannot be understood)