Work Breakdown Structure in Project Management

Revision as of 19:09, 4 March 2022

Abstract

Project Management is often a complex process involving Stakeholders, Teams, Development Approaches, Planning, Project Work, Delivery, Measurement, and Uncertainty. As part of Planning and Delivery it is important to define the Scope and Requirements in order to break down the complex tasks into manageable sub-tasks of the whole project (PMBOK; Seventh Edition, 2021, p. 81)^[1]. Therefore, in this Wiki article, the Work Breakdown Structure (WBS) will be presented as a Project Management method used to reduce the complexity of a project by delimiting the whole project plan into manageable sub-tasks. This Wiki article will further cover context and history of WBS along with explanation on how to use it in Project management and what are the principles, advantages and limitations of this method. Since WBS is very flexible and easily applicable tool, the article will focus on most popular ways of application specifically used in Projects.

Context and Historical Applications

Historically, the Work Breakdown Structure method was inspired by Program Evaluation and Review Technique (PERT) used by United States Department of Defence (DoD). In 1968, along with aerospace industry and National Aeronautics and Space Agency(NASA) DoD has published a "Work Breakdown Structures for Defence Materiel Items" (MIL-STD-881). Similarly, NASA has adopted WBS and has a handbook of its own. https://ntrs.nasa.gov/citations/20180000844 WBS in both organisations are used for Programs, Products and Projects.

WBS Terminology, Principles and Framework

Before diving into the framework of Work Breakdown Structure and its applications it is important to understand the main terms and principles. Therefore, this section will cover main terms of WBS along with explanations and principles with their impact to the use of method.

Terminology

WBS Levels - A visual and coded arrangement or configuration of a WBS which enables the hierarchy of a projects to deliverables and deliverables to work packages and tasks. (Nasa)

Deliverable - Usually expressed in nouns/adjectives, the deliverables are the work products of the project. They are aimed to describe "what" of a project with an intention to express results and not only actions. They are usually visualised as a separate box in WSB template and have a specific code assigned to it.

Work Package - The lowest level of a deliverable which contains a clear identification of tasks, activities and milestones that have to be delivered in order to fulfil the deliverable.

Principles

Decomposition - As indicated by the naming, this method relies on Breakdown principle often called Decomposition. The main idea of this is that the project has to be decomposed into a deliverables with a level of detail which would precisely capture the whole scope of the project and at the same time maintain that level of detail for effective communications, task divisions and control.

100% rule - Following the principle of Decomposition it is important to keep the scope of each deliverable in line with the whole project and its limitations. Therefore the 100% rule is essential when developing WBS and it states that each level of WBS decomposition has to make 100% of the work of its parent element. (pg 23 Norman).

Project Scope - Each deliverable and element of WBS has to be within project's scope and any tasks that do not belong to the project, should be left out.

Framework

The framework of WBS consists of three main parts being: 1)Visual representation 2)WBS Dictionary 3)Project Schedule

Visual representation can be made in various ways but the most common format used in project management is Tree view. The tree view clearly depicts levels of the WBS and indicates the coding assigned for each deliverable

WBS dictionary contains descriptions of each deliverable and its assigned code. For example deliverable coded with 1.2.1 would be described in WBS dictionary 1.2.1.

Lastly, the visual depiction and WBS dictionary can be used to take the deliverables and use them for project planning. Here Project Schedule template can be used to transform the tasks from WBS lowest level to the Schedule.

Visual Representation

Tree view

As mentioned before, the most common way of representing WBS is by the use of Tree structure otherwise known as Organisational Chart. The main reason for its popularity between WBS users is that this kind of visualisation allows to present "child" and "parent" dependencies between deliverables. In this case, the child elements are visualised as a smaller boxes which are conected by lines with the parent elements higher in the structure. With this kind of representation, the whole project can be decomposed into smaller elements and code structure can be still maintained by identifying the code in each box. Lastly, levels could be indicated for easier decomposition visualisation. The example of Tree view of WBS can be seen in Figure 1.

Figure 1: Work Breakdown structure: Tree view visualisation, inspired by the “Practice Standard for Work Breakdown Structures”-Second Edition (2011)

Tabular view

Another type of WBS visualisation is Tabular view. In this case, the levels of WBS along with hierarchy and coding of elements is done by table columns. This type of visualisation can be made using simple tools such as Excel and therefore is a popular choice between people with limited design tools. A potential dissadvantage of this representation can be increased complexity when dealing with big WBS structures since modeling in tabular forms is demanding process.

Figure 1: Work Breakdown structure: Tree view visualisation, inspired by the “Practice Standard for Work Breakdown Structures”-Second Edition (2011)

Outline view

The last visualisation used for WBS is Outline view. This kind of visualisation has numbered levels for each element along with its coding. The main tools used for outline view are regular office tools such as word processor and excel. Outline view can be seen in Figure 3 .

Figure 1: Work Breakdown structure: Tree view visualisation, inspired by the “Practice Standard for Work Breakdown Structures”-Second Edition (2011)

Enhanced Uses

WBS Application in Project Management

Given main principles and the different approaches to visualizing WBS there is still room for different methods of its application in project management, these methods will be covered below.

Top-down

One of the most common approach of WBS application is Top-down. As the naming suggests, the WBS application starts from the main project in level 0 and later is decomposed into major deliverables in lower levels. The suggested appraoch contains four main steps:

Step 1: Identificcation of the final product, service or result that would be a goal of a sucesfull project. Following this step, the project team should review existing documentation to ensure that the final goal as within project scope and that there is no missmatch between project requirements and WBS.

Step 2: Definition of project major deliverables of level 1. These deliverables should be seen as a interim goals which are needed for project success but does no satisfy the need as a single entity. This process can be carried in a itterative manner considering the 100% rule.

Step 3: Decomposition of project main deliverables to lower levels which would contain a level of detail needed for the project management and task definition. In this step so called work packages should be defined to work as a stand-alone deliverables. This step can also be carried out in a itterative manner considering the 100% rule.

Step 4: Revision of WBS to match stakeholder needs. The main goal of this step is to develop a WBS which would reflect the whole project in terms of planning, execution and control to convince and infrom stakeholders.

Bottop-Up

In contract, the project group can choose to start the construction of WBS by the work package definiton and work their way up to the definition of the final project. It is important to not get carried away when following this method. There are 6 main steps needed when developing WBS trough Bottop-Up approach:

Step 1: Starting from the lowest level - work packages, identify all deliverables involved in the whole project. It is important to keep only one deliverable per work package.

Step 2: Group related work packages together based on their focus, area and relation towards the project.

Step 3: Aggregation of the deliverables towards upper level to form a parent-child structure. After this step the team should make sure that current structure follows the 100% rule.

Step 4: Revision fo the structe. After the step 3, the team should make sure that current structure follows the 100% rule and that all of the work has been included in the WBS structure.

Step 5: Aggregation towards Level 0. Here the steps are repeated until the deliverables make up the whole project and level 0 is reached.

Step 6: Revision of WBS to match stakeholder needs. The main goal of this step is to develop a WBS which would reflect the whole project in terms of planning, execution and control to convince and infrom stakeholders. Iterative

WBS Tools

Advantages

Limitations

Annotated Bibliography

References

1. ↑ Project Management Institute. “A Guide to the Project Management Body of Knowledge (PMBOK)”- Seventh Edition, 2021, p. 81