Managing Scope using the ‘Decomposition Model’

Read it in 0 Mins

Last updated on
28th Aug, 2019
17th Oct, 2017
Managing Scope using the ‘Decomposition Model’

One of the common problems faced by many an organization is the fact that they are unable to make sure that their initiatives for change deliver positive results. 

Solution Scope and Project Scope
Organizations take up projects to solve business problems or to take advantage of opportunities. In order to satisfy these needs and wants of internal or external stakeholders they end up doing projects, that may be to create a product, service or create some form of result.  Organizations embark on projects with a clear objective in mind and with a ironed out project and solution ‘scope’. As we all know, scope defines the boundary and can be solution (or product) scope that defines the features and behaviours of the solution and project scope that defines the project’s boundaries in terms of triple constraints (time, cost and scope) along with quality requirements.

However, projects fail since the scope is not managed properly. One common problem of not managing scope properly is the resultant scope creep. Scope creep (again solution or project scope) refers to the unexpected and uncontrolled expansion of scope. It is important to note that an increase or decrease in solution scope may result in an increase or decrease in project scope and vice versa.

Why does scope creep happen?
Identifying the scope of the solution and of the project is no easy task. It is a task which most organizations get wrong. Often the responsibility of defining the solution scope rests with the Business Analyst and defining the project scope lies with the project manager role in manageing Scope . But why does scope creep still happen?

Scope creep normally happens as a result of not identifying the scope properly,  not defining the scope adequately and clearly enough, not documenting the scope in enough detail and as a result of not getting the consensus or agreement about the scope from all relevant stakeholders. Scope creep may also happen as a result of not getting all relevant stakeholders involved at the inception itself. It is important to also note that the reasons for scope creep are not at all limited to above. 

Decomposition Model to the rescue!!
As the name suggests, decomposition modeling involves breaking down something to the most detailed level into its constituent components. Decomposition modeling is a technique that is applicable in many a context. The organization chart or an Organization Breakdown Structure (OBS) with reporting hierarchies defined is a decomposition model applied in the context of an organization’s human resources. A Resource Breakdown Structure (RBS) is a decomposition model often applied in the context of the resources applied to a project. A Cost Breakdown Structure (CBS) can be used to view how cost components can be allocated to work components. All above can be identified as examples of how the decomposition modeling technique can be applied to manage project scope.

The BABOK® and the PMI-PBA® guide defines a solution scope decomposition model based on the features to be implemented and based on the tasks or work to be completed. The decomposition model when applied for solution scope, can be depicted using a Work Breakdown Structure (WBS) or a Feature Breakdown Structure (FBS). 

A feature breakdown structure allows the consultant to start the analysis from the entire subject and break it down into its constituent features. This is known as functional decomposition. In a task for work breakdown structure the consultant will start with the largest piece of work to be completed and break it down into smaller parts until it is broken down into the lowest level which is called a work package.

A decomposition model may be drawn as a hierarchical diagram or even be written down in text format. A proper numbering format is recommended to be followed in order to better manage relationships among components. For example level one can be the entire scope of the engagement that is to build a mobile application for backpackers visiting a country. The second level can be the fact that the mobile application must connect to social media channels of the user, allow the user to search for locations on a map, be able to collaborate with other travellers and so on. The 3rd level can be the fact that the user must be able to share posts on Facebook or Instagram and so on.

How does Decomposition Model help manage scope?
The decomposition model provides a visual representation of the entire scope of the engagement. A properly detailed functional decomposition model will help visualize the everything that is in scope on one single canvas. It will help present the scope to all stakeholders and get the buy-in from everyone for the same. A properly documented decomposition model will definitely become a good reference point whenever there is deliberation about new requirements or when there is discussion about the scope of each feature.

So, choose to draw a decomposition model wisely. It will definitely make everyone’s lives easier in terms of managing project and solution scope.



KnowledgeHut is an outcome-focused global ed-tech company. We help organizations and professionals unlock excellence through skills development. We offer training solutions under the people and process, data science, full-stack development, cybersecurity, future technologies and digital transformation verticals.