Do you know that most of the bugs in software are due to incomplete or inaccurate functional requirements. The software code, doesn’t matter how well it’s written, can’t help but produce bugs if there are ambiguities in requirements.
It’s better to catch the requirement ambiguities and fix them in early development life cycle. Cost of fixing the bug after completion of development or product release is too high. So it’s important to have requirement analysis and catch these ambiguous requirements before design specifications and start of project implementation phases of SDLC.
How to measure functional software requirement specification (SRS) documents?
We need to define some standard tests to measure the requirements. Once each requirement is passed through these tests you can evaluate and freeze the functional requirements.
Let’s take an example. You are working on a web based application. Requirement for this application is as follows:
‘Web application should be able to serve the user queries as early as possible.’
How will you freeze the requirement in this case?
What will be your requirement satisfaction criteria? To get the answer, ask this question to stakeholders: How much response time is ok for you?
If they say, we will accept the response if it’s within 2 seconds, then this is your requirement measure. Freeze this requirement and carry the same procedure for next requirement.
We just learned how to measure the requirements and freeze those in design, implementation and testing phases.
Now let’s take other example. While working on a web based project, client (stakeholder) has specified the project requirements for initial phase of the project development.
Manager circulated all the requirements in the team for review. When discussion started on these requirements, everyone was having his or her own conception about the requirements. We found lot of ambiguities in the ‘terms’ specified in requirement documents. Client used many ambiguous terms, which were having many different meanings, making it difficult to analyze the exact meaning. The next version of the requirement document from client was clear enough to freeze for design phase.
From this example we learned ‘requirements should be clear and consistent’
Next criteria for testing the requirements specification is ‘Discover missing requirements’
Many times project designers don’t get clear idea about specific modules and they tend to assume some requirements while design phase. Any requirement should not be based on assumptions. Requirements should be complete, covering each and every aspect of the system under development.
Specifications should state both type of requirements i.e. what system should do and what it should not.
For checking the requirements completeness, divide requirements in three sections – ‘Must implement’ requirements, requirements those are not specified but are ‘assumed’ and ‘imagination’ type of requirements. Check if all types of requirements are addressed before software design phase.
Check if the requirements are related to the project goal.
Sometimes stakeholders have their own expertise, which they expect to come in system under development. They don’t think if that requirement is relevant to project in hand. Make sure to identify such requirements. Try to avoid the irrelevant requirements in first phase of the project development cycle. If things are not clear then ask questions to stakeholders such as ‘why you want to implement this specific requirement?’ This will describe the particular requirement in detail making it easier for designing the system considering the future scope.
But how to decide the requirements are relevant or not?
Simple answer: Set the project goal and ask this question: If not implementing this requirement will cause any problem achieving our specified goal? If not, then this is irrelevant requirement. Ask the stakeholders if they really want to implement these types of requirements.
In short requirements specification (SRS) document should address following:
- Project functionality (What should be done and what should not)
- Software, Hardware interfaces and user interface
- System Correctness, Security and performance criteria
- Implementation issues (risks), if any
In simple words Requirement Specification Testing is as follows:
“Requirements should be clear and specific with no uncertainty, should be measurable in terms of specific values, should be testable having some evaluation criteria for each requirement, should be complete, without any contradictions”
Testing should start at requirement phase to avoid further requirement related bugs. Communicate more and more with your stakeholder to clarify all the requirements before starting project design and implementation.