Documentation is one of the key responsibilities of a business analyst. There are many types of documents that a business analyst will be responsible for creating and I have mentioned them in my previous article also. However, there are some documents that you might feel difficult to differentiate i.e. Business Requirement Document (BRD), Functional Specification Document (FSD), and Software Requirement Specification (SRS).
All these documents talk about the requirements but the difference is there based on;
- Who creates them?
- What level of information is available in these documents?
- In what stage these documents are being created?
- Who uses these documents?
- What’s the purpose of the document?
Let’s compare them together and see the key difference between BRD, FSD, and SRS documents. But before we compare, it is important to know each of these documents and its purpose in a project.
Business Requirement Document (BRD)
Business Requirement Document i.e. BRD is created during the initial phase of the project. This document contains the high-level business requirements that could be easy to follow by business stakeholders, managers, board of directors, etc. This document is also referred to as Business Requirments Specification i.e. BRS.
In a nutshell, a business requirement document is a functional business requirement that is written in a well-structured manner without any technical jargon. This document is prepared during the initial phase of the project with the help of business stakeholders and key end-users.
Business Requirement Document explains what functionality system should have and answers the “Why” part of the system requirements. It lists the business stakeholders’ requirements and expectations from the system. For an example, the requirements for an online banking platform could be similar to following;
- Bank customers should be able to register themselves.
- Registered bank customers should be able to log in.
- Customers should be able to do online transactions.
- Customers should be able to open fixed deposit online.
- Customers should be able to recharge their mobile phones, etc.
Since the BRD is prepared during the initial phase of the project and it is one of the output from the requirement elicitation process, it is prepared by the business analysts. This document is referred by the business users and the stakeholders’ approval required on this document to proceed with planning and development steps.
Functional Specification Document (FSD)
Business Requirement Documents are built with high-level business requirements and stakeholders needs and expectations from the system. This document is good to be referred by the business users but it does not have sufficient information for the development team. Therefore, a functional specification document is required with detailed requirements in technical terms that will be referred by the technical team for further development of the system. The FSD requirements for the online banking system could be like below;
- Username should not include numeric value.
- The password should be 8 or more char long.
- Only 5 transactions should be allowed in a day, etc.
A functional specification document described “How” the system is going to function. In other words, FSD is a technical response to the needs set out from the requirement document and your business objective. In a software or other technical project, a functional specification document is the start of a conversation in a technical term about what we are going to deliver. It can be seen as a guideline or reference document of the system that will be referred by the developed team.
This document focused on the system’s capabilities, its appearance, and interaction with end-users and other components with other connected systems. This document is also known as Functional Specification Requirement (FSR), Functional Specification, Product Specification.
FSD is the basis for the development and Testing team to plan their development strategies and build the test scenarios. This document is a technical and prepared by the business or systems analyst
Software Requirement Specification (SRS)
Software Requirement Specification i.e. SRS Document is one of the important documents for the development team. It is a complete description of the behavior of a system to be developed. It documents what requirements must be fulfilled to satisfy the business requirements. It also describes all the user interaction with the system with the help of use cases.
SRS document contains all the functional and non-functional requirements along with the use cases that the software must meet. It includes complete business requirements, system properties, constraints, and behaviors e.g. system’s reliability, response time, storage requirement, etc. Therefore it is also used for estimating the cost and effort required for developing that software.
In a nutshell, a software specification requirement document elaborates on the business requirements mentioned in BRD to accommodate the functional and non-functional requirements along with user intersections with the system i.e. use cases. Therefore, you might not find this document in small projects because for them BRD and FSD documents are enough to develop a system.
This document is prepared by system analysts or business analysts and referred by the project management, development, and implementation teams. This document is also known as System Requirements Specification (SRS) and Product Requirements Document (PRD)
You can check out this book on Requirement Writing on System Engineering
Difference Between BRD, FSD, and SRS
Let’s see the side by side comparison based on the document content, audience, author, and project phase when it gets prepared.
|Based on||BRD or BRS||SRS||FRD|
|What it includes?||BRD or a BRS includes the high-level business requirement of a system to be developed in layman language.||SRS document includes the functional and non-functional requirements and Use Cases.||FRD document consists of detailed requirements in technical terms and technical diagrams like UML, Data Flow, etc.|
|What is Answers?||BRD answers the WHY part i.e. Why the requirements are being prepared?||SRS answers the WHAT i.e. What requirements to be fulfilled.||FRS focuses on the HOW part i.e. How the requirements will be implemented.|
|When will it be prepared?||A BRD document is created during the analysis phase of the project.||SRS document is prepared during the planning phase of the project.||FRD or FRS document is also created during the planning phase of the project.|
|Who will be responsible for creating?||A BRD will be created by the business analysts.||Business Analyst and System Analyst work together to prepare an SRS document.||Since the functional requirement document is detailed and technical, it is created by Business Analyst, System Analysts, and Implementation team together.|
|Who will be using?||Business Requirements Document is developed for the business users, stakeholders, etc.||SRS document is prepared for the subject matter experts and technical leads.||FRD document will be used by the development team and quality assurance i.e. testing team.|
- Writing Quality Business Requirements Document
- 10 Important Documents Prepared By Business Analyst
- Key Difference Between Business Analyst And Data Analyst
All three documents i.e. Business Requirements Document, Functional Requirement Document, and Software Requirement Specification Document is critical for any project. However, they are not the same document.
The difference between BRD, FRD, and SRS is based on their author, audience, content, and purpose. Now, you know the key difference between them in this article.
I believe you found this article useful and it was sufficient to clear your doubts regarding the difference between BRD, FRD, and SRS. Please share it with your friends and subscribe to the BABeginners mailing list.
Frequently Asked Questions
IS BRD and FRS the same?
No! Business Requirements Document – BRD and Functional Requirement Specification – FRS or FSD are different. BRD consists of business requirements in layman language and FRD or FRS elaborate the requirements in detail with technical diagrams like UML, Data Flow, etc.
Is BRD and SRS the same?
No! BRD consists of high live business requirements without any technical jargon whereas the SRS document consists of functional and non-functional requirements. BRD is used by the stakeholders but SRS documents are referred by the SMEs and technical leads.