(Professional Business Analyst Training

organisation)

FunctionalDecomposition

Functional Decomposition: Functional decomposition relates to the various functional relationships as how the original complex business functions were developed. It mainly focuses on how the overall functionality is developed and its interaction between various components. 

Functional Decomposition is used to break down the high-level solution scope of a project into its component parts. Then create a model of what needs to be done to deliver all or part of the solution. Functional decomposition is an outstanding way to break things into manageable pieces and understand the relationships between those pieces. 

Business Analysts use Functional decomposition technique during the requirements analysis phase of a project to break either an organizational unit or the solution scope into its component parts.  Each outcome may have its own set of requirements.

Traditional BA (Waterfall) Agile BA

Requirements are documented in Use Cases,Business Requirements, Functional requirements, UI Specifications, Business Rules.

Requirements are documented in Epics, User Stories and optionally Business (or Essential) Use cases.

   

Focuses on completeness of requirement and spends time in ensuring the requirement is unambiguous and has all the details.

Focuses on understanding the problem and being the domain expert so that s/he can answer questions from the development team swiftly and decisively.

Focuses on getting a ‘sign off’ on the requirements.

Focuses on ensuring the requirements meet the currentbusiness needs, even if it requires updating them.

Often there is a wall between the BA/Business and the Development team.

Agile BA (Often called as Product Owner) is part of the team.

Tends to dictate solutions.Has to remain in the problem domain, leaving the development team ‘space’ to explore different solutions.

Long turnaround. Quick turnaround.

Focus on what the requirements document said. In other words, output (Artifact) is a well written thorough requirements document.

Focus on the functionality of the developed software. In other words, output (Artifact) is the software that meets thebusiness needs.

   

Large or complex functionalities are more easily understood when broken down into pieces using functional decomposition.” 

 

When and How•Functional Decomposition comes into picture in project requirement analysis phase in order to produce functional decomposition diagrams as part of the functional requirements document.•After formal discussions with business analysts and subject matter expertise Functional Decomposition will be done.

Decompose the components with their functions from root and continue to decompose to lower levels until a sufficient level of detail is achieved.Perform an end-to-end observation of the business operation and check each function to confirm that it is correct.