DChirikov
Classic PM: WBS
 
  2025-11-07 23:55:26   2025-11-08 16:50:39

Abstract

It is one of the tools of the Project Manager, who is the main person for managing the Scope of the Project, planning based on it, all other areas of the Project. Since the Work Breakdown Structure, WBS is the foundation for the whole Project, its creation depends on a lot - that’s why this tool is dedicated to a separate article.

Terms

Before considering the tool, it makes sense to deal with the terms that will be used in the future.

Work - actions of a physical or mental nature, the purpose of which is to achieve certain goals by avoiding emerging problems. In project management, is associated with actions to create Deliverables (production of products or delivery of services), which are its outcomes.

Structure - something organized according to a certain logic.

Deliverables - any unique product or service that is the result of a Project or Project Phase.

Decomposition - an action whose result is broken down into smaller and easily manageable parts, Deliverables. These parts of the result make it easier to manage, evaluate, and perform the work required to achieve the result.

Hierarchical - classified by some characteristics entity that knows level structure.

Work Breakdown Structure, WBS - project-focused, broken down into smaller and more manageable parts, a hierarchically structured structure that defines the work to be performed by the Project Team.

WBS has the following characteristics:

  • Assists in the definition of all work required to achieve project objectives;
  • Hierarchical Illustration of Deliverables;
  • Breaks down project results into smaller and easier to manage elements.

Activity is one of the components of work that must be performed to create a project result.

Apportioned Effort - labor intensity in relation to project work, which is difficult to separate but which is directly proportional to the measured discrete labor intensity.

Control Account is some kind of checkpoint where you compare what has been done with what was planned to be done at that time. Typically uses the Earned Value Method.

Discrete Effort - labour intensity which is directly comparable to certain elements of the hierarchical work structure and delivery results and which can be directly planned and measured.

Level of Effort is an auxiliary operation that does not directly contribute to the creation of Deliverables. For example, quality audit operations, organizational operations etc.

Task is a job that is defined by industry, project area or other similar factors.

Work Package - The Deliverable or a set of works allocated at the lowest level in the branch. Work packages should lead to the creation of project results. Work Package contains Activities, which are their component parts (can also contain Level of Effort).

WBS Element - any element of the Work Breakdown Structure, WBS.

Rule 100%

Rule 100% (Hugan, 2002) is one of the basic principles of WBS construction. This rule comes down to the fact that all children of each WBS element must make up 100% of the work of that element. Thus, to complete the Project, it is necessary to perform all elements of WBS on the first level, they make up 100% of the work of the whole Project. To complete each element on the first level, it is necessary to execute all of its child elements that make up 100% of it. In the diagram below, this is clearly shown - under the name of each element is indicated its share in the completion of the parent element:

PMI: WBS Rule 100%

WBS Decomposition should be made to such an extent that it is convenient for you to control. What kind of WBS it will have does not really matter; it can be presented as a tree diagram or in tabular form. The original presentation was presented above; the text and table are also presented below:

    1. Project
    • 1.1. First element
    • 1.2. Second element
      • 1.2.1. First element
        • 1.2.1.1. First element
        • 1.2.1.2. Second element
        • 1.2.1.3. Third element
      • 1.2.2. Second element
    • 1.3. Third element
Level 1 Level 2 Level 3 Level 4
1. Project 1. First element    
1.2. Second element    
1.2.1. First element  
1.2.1.1. First element
1.2.1.2. Second element
1.2.1.3. Third element
1.2.2. Second element  
1.3. Third element

How to use WBS for Project Management

Of course, the Work Breakdown Structure, WBS does not guarantee the completion of the Project, but it has the following features:

The absence or incorrectness of WBS can lead to:

  • unfinished WBS can lead to off-project work;
  • project goals and objectives are not correctly defined;
  • exceeding the Cost;
  • uncontrolled increase of Time;
  • lack of one or more project results.

Interaction with other processes

WBS is created to simplify the work of the Project Manager, but among other things, WBS either uses the results of the processes or is itself used by other processes.

Interaction with other instuments

In addition to interacting with processes, WBS often interacts with project management tools.

  1. Project Charter. The Project Charter is always the foundation for the Project, and therefore everything that is carried out on the Project in the future, in one way or another, is based on it - WBS is not an exception. The elements of the first level of the WBS are always the Deliverables prescribed in the Project Charter;
  2. Project Scope Statement is a logical continuation of the Project Charter, which details the Project Scope. WBS is largely based on the Project Scope Statement;
  3. WBS of the Program and Portfolio. Since a Project may be one of the Deliverables of the Program or the Portfolio, it is possible to create a WBS in which projects will be part of the Program or the Portfolio. Thus, it turns out that the branch of Portfolio - Program - Project, can be continued by WBS of the Project;
  4. Hierarchical Resource Breakdown Structure, RBS. The Project Manager can (should) establish a link between the elements of WBS or RBS to bind the Work Packages to the members of the Project Team;
  5. Organizational Breakdown Structure, OBS. Helps to bind Work Packages to an organizational unit (for example, to a department);
  6. WBS Dictionary. Since the WBS Dictionary describes the elements of the WBS in more detail, it often helps to identify errors in the WBS itself;
  7. Network Diagram. WBS is the main input to Define Activities, and the network diagram uses outputs of this process (a well-written WBS - a well-written Network Diagram - a well-written Schedule - less time lag problems). The Network Diagram sometimes helps to identify a certain number of errors in WBS;
  8. Project Schedule. This is the result of combining all the above-mentioned tools to create a realistic and most effective Schedule.

Define a WBS quality

Two fundamental principles are at the heart of WBS.

First principle

A well-built WBS is one that meets all the Requirements of the Project.
Key characteristics to be followed by each WBS are as follows:

  • WBS is a diagram representing project elements as Deliverables;
  • defines the Scope of the Project;
  • provides Scope of the Project to all Stakeholders;
  • contains 100% of all work on the Project;
  • includes internal, external and transient Deliverables required to complete the Project including project management;
  • each level below contains 100% of the work to be completed by the parent;
  • contains Work Packages, which clearly define the required Activities;
  • WBS can be executed in graphical, tabular or textual form;
  • all names of elements are adjectives or nouns;
  • classifies all major and minor Deliverables;
  • Team members and the Project Manager define the hierarchy of elements of WBS;
  • WBS has at least two levels with at least one level of Decomposition;
  • created with the participation of those who will carry out the work;
  • created with the (partial) participation of key Stakeholders and Subject Matter Expert;
  • constantly replenished as the Progressive Elaboration project;
  • changes only after making a Change Request through the Integrated Change Control.

The main characteristics of WBS were presented above. The main features that contribute to a successful WBS will be presented below.

  • achieving a sufficient level of decomposition Decomposition. The depth of Decomposition must be appropriate to the size and complexity of the project;
  • provide a sufficient level of communication between the WBS Elements;
  • meet the requirements of the Project or organization to track progress. For this, the WBS can contain checkpoints on which performance is analyzed. Such points can also be marked as communication, i.e., those on whose occurrence there is a notification of the Stakeholders about the progress of the work. Among other things, the elements of the WBS should be structured in such a way that their implementation can be tracked;
  • reach level for controlling Activities. Activities that are part of the Work Packages must be of sufficient size to control their execution;
  • may contain project-specific elements;
  • WBS is designed as a logically linked structure that facilitates the satisfaction of all customer’s Requirements.

Second principle

All characteristics of the WBS are equally applicable to all types of the WBS.

Frequently occurring consequences of a bad WBS or its absence:

  • Extension of project Deadlines and deviation from the final project Deadlines;
  • Project goes beyond the Cost;
    • Is the detail of WBS sufficient to count project completion?
    • Is the Earned Value Method used to analyze project Execution?
  • Some project users cannot use the Deliverables;
    • Are the large Deliverables broken down into smaller ones (this contributes to the lack of unaccounted-for elements of WBS)?
    • Are the elements of the WBS oriented to Deliverables?
    • Are the elements of implementation or learning to use Deliverables taken into account?
  • The Scope of the Project is out of control;
    • Can I use the WBS?
    • Which works are included in the WBS?
    • Is the WBS flexible (for changes)?
    • Did the changes in WBS occur when the required Change Requests passed the Integrated Change Control process?
  • Team members are not familiar with their assigned job;
    • Is the WBS detailed?
    • Does the WBS include all specific works?
    • What Stakeholders are familiar with the WBS?
  • Some work not done;

WBS generation

There are several methods for WBS generation. Some of them are presented bellow.

Top-down

  1. Determination of the Deliverables that must be created for the Project to be considered successful;
  2. Definition of the main Deliverables, which are de-facto secondary, i.e., do not lead to the achievement of the business goal;
  3. Decomposition of the main Deliverables to a level sufficient for management and control. Remember that the sum of work on each branch must be 100% work to realize their parent element. Also, each Work Package must contain no more than one Deliverables;
  4. Update WBS as the project progresses.
Pros Cons
Structuring is more convenient for reporting You can miss some Work Packages out of sight, requires attention
Helps to ensure that the structure is logically structured Requires care to maintain a sufficient level of detail
Useful in brainstorming and determining Deliverables
Helps to identify Deliverables if they have not been noticed previously

This approach is used in cases where the Scope of the Project is poorly known or the Project Team has not encountered similar projects before, and the Project Team or Project Manager does not have experience in creating WBS. Therefore, there are no similar patterns.

Bottom-Up

  1. Identify all Deliverables (or Work Packages) required in the Project;
  2. Logically merge the Deliverables (or Work Packages) into groups;
  3. Merge all Deliverables previously grouped into groups to the next top level. The amount of work on each branch must be 100% of the work for the realization of their parent element;
  4. At the end of the merge, check whether all Deliverables are taken into account;
  5. Carry out Step 3 and Step 4 until the upper level of WBS is reached and there is only one element left that should meet the project objective;
  6. Update the WBS as the project progresses.
Pros Cons
All Work Packages and Deliverables, defined before Decomposition Requires identification of all Deliverables prior to creating an WBS
Ensures that all Work Package will be taken into account No guarantee that all Work Packages are grouped correctly
It is possible to fluctuate from the objectives of the Project, assigned in the Project Charter

This approach is applied when the Scope of a Project is well understood and similar projects have been carried out previously. Also this method can be successful if there is a template WBS - the team of the project just looks at the existing template WBS and slightly changes it.

WBS (Organizational) Standards

Most companies practicing the PMI project management methodology already have standards in place that define the rules for building a WBS. The standard can include both listing all necessary elements, as well as naming rules for elements, numbering rules for elements, etc.

Pros Cons
WBS formats defined in advance Binds project to standard
Enables the use of WBS in subsequent projects The standard may include unnecessary project Deliverables or Work Packages
Standard may not be suitable for all projects

WBS Templates

If the Project is carried out in a company that has carried out similar projects previously, it would be advisable to take the previously created WBS as a basis - this will help to avoid errors, in particular the absence of some elements. Of course, this approach reduces the time needed to create a WBS, but it is not guaranteed to eliminate errors.

Pros Cons
Initially provides the WBS Requires compliance with draft standard
Enables the use of WBS in subsequent projects Template may include unnecessary project Deliverables or Work Packages
Can help determine the appropriate level of detail (based on previous work) Standard (previously applied to template) may not fit all projects

However, it is quite common to use a combination of all the methods presented above, for example, you can take as a basis an existing template applicable to corporate rules and finish it up to the specific needs of the Project using the Top-down method. Whatever method is used, remember that project planning processes are iterative processes, and the process of creating/modifying WBS is not an exception. Thus, with each subsequent iteration, it is assumed that the WBS will be compiled more and more qualitatively and fully.

 Comments
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  1. Abstract
  2. Terms
  3. Rule 100%
  4. How to use WBS for Project Management
    1. Interaction with other processes
    2. Interaction with other instuments
  5. Define a WBS quality
    1. First principle
    2. Second principle
  6. WBS generation
    1. Top-down
    2. Bottom-Up
    3. WBS (Organizational) Standards
    4. WBS Templates
  1. Abstract
  2. Terms
  3. Rule 100%
  4. How to use WBS for Project Management
    1. Interaction with other processes
    2. Interaction with other instuments
  5. Define a WBS quality
    1. First principle
    2. Second principle
  6. WBS generation
    1. Top-down
    2. Bottom-Up
    3. WBS (Organizational) Standards
    4. WBS Templates