Software Requirements Specifications (SRSs) constitute a tech document with various software features, capabilities, coding test,s and functions that are to be implemented in the product. These parameters also include characteristics, design details, and implementation obstacles for the development team. The structure of SRS can be modified, depending on the project, and various features/functions can be added during the process.
SRS lies in the initial, bottom stage of the entire development process. The next stages include user requirements, which describe the needs of end-users and describing beyond the goal of the final product (business requirements).
No matter how the SRS structure is shifted during the development process, functional (if/then behaviors, workflow description, data handling logic, data inputs/outputs) and non-functional requirements always take place. The first requirements, basically, are features and functions that allow the system to run as expected, the second ones are sort of quality attributes that explain specific constraints and characteristics to be considered by the system.
The most common types of NFRs are usability, scalability, performance, compatibility, portability, accessibility, reliability, security, localization, and so on. In fact, there may be hundreds of NFRs, depending on the project.
Main Software Development Models
Now let’s get straight to business.
There are 2 major models of the software offshore development process:
Waterfall Software Development
The Waterfall model is the standard development model where all development stages are carried out sequentially – the next stage begins after the full completion of the previous one.
Although a high pace is something that’s mostly not associated with the Waterfall model, it’s still the best for less experienced dev teams – the model provides more time for writing SRSs. Thus, if your business needs detailed requirements that are to remain unchangeable in the nearest future as a solid document, Waterfall is a great option.
The Waterfall model includes the following steps in the software development process:
- Requirements identification;
The first step is to do an agile approach defining the technical parameters of the future program. After that, the team needs to confirm the list of requirements for the software. Then comes the сoncept stage, where the dev team studies all documentation, created to explain to them the plan and method of requirement realization.
Once the concept stage is complete, the dev team performs the inception of the project, where all the components of the project are integrated.
Only after these stages are fully completed is the final product gets tested and debugged. Then follows the implementation (construction) stage, release, production, and support, including bug fixes and new functionality integration.
Thus, all the stages of software development using the Waterfall model are carried out strictly sequentially. There is no going back to the previous stage just as there is no stage skipping/overlapping.
The main advantages of the Waterfall approach are:
- Clear documentation of the process;
- Accurate budget and deadline definition;
- Low dependency on the human factor.
The main disadvantages of the Waterfall approach:
- Long timeframes from project start to the first result;
- A large volume of documents;
- Continuous coordination of requirements and intermediate documents;
- Inability to make dynamic changes.
Agile Software Development
A set of software development methodologies that involves collaboration between customer representatives and developers, Agile development methodology is based on an iterative approach, the dynamic formation of requirements, and their implementation in short steps.
The Agile approach implies repeated user feedback collection and implementation of modifications to the SRS structure performed by a business analyst (BA) every 2 weeks or every month. This is needed for proper software development, i.e. the module-by-module method – once the development team finishes one module, a BA should perform an acceptance test, to verify if the module meets all the requirements.
The result of each such stage, including the iteration cycle, is a certain miniature software project.
There are several methods of Agile software development, the most famous are Scrum, Extreme Programming, DSDM, Incremental, and Evolutionary strategy.
The Agile principlesof software development include the following 12 important points:
- Customer satisfaction through rapid and uninterrupted delivery of required software;
- Acceptance of changes in requirements even at the end of the development process (this can increase the competitiveness of the resulting product);
- Frequent delivery of working software (every month/week or even more often);
- Close, daily communication between the customer and the dev team throughout the entire project;
- The project is managed by motivated experts, provided with decent working conditions, support, and trust;
- Personal (face to face) conversation is the recommended method of communicating information;
- Working software is the best measure of progress;
- Sponsors, devs, and users should be able to maintain a steady pace indefinitely;
- Constant attention to improving technical craftsmanship and user-friendly design;
- Simplicity is the art of avoiding unnecessary work;
- The best technical requirements, design, and architecture come from a self-organized team;
- Constant adaptation to changing circumstances.
The main advantages of Agile software development:
- Minimal risk;
- Gradual product functionality increase;
- Low documentation scopes;
- Basic version launch in the shortest possible time.
There are also disadvantages:
- Impossibility to determine the exact budget of the project;
- Impossibility to determine the exact completion dates;
- Not suitable for gov and budget organizations;
- Requires motivation from the responsible customer representatives.
- Scrum is a sprint-based method when the working product version must be ready in a month or sooner (starting from 1 week). In Scrum, tasks are added to Jira right away, which can help you configure requirements, simplify the test case traceability process, and also adds sharing, viewing, and commenting features.
There’s no BA to explain details to the team, and a product owner is focused solely on the long-term project. Scrum is usually a good option for skilled development teams that know exactly what to do.
- Extreme Programming (XP) is an Agile approach that implies interacting with the client at every stage. Thanks to XP, shortcomings of the previous stages and the required functionality of the product along with other parameters are identified.
- DSDM is an iterative and incremental approach and submethod of Agile software development that emphasizes sustained user/consumer participation in the process.
- An incremental approach is one of the first models of Agile software development. This strategy is based on the full definition of all requirements for the software tool (system) to be developed at the beginning of the development process. This approach provides progress towards the final goal in steps, with each step providing a part of the overall functionality of the project.
The parts (subprojects) get prioritized, and each of them, in certain cases, is developed according to its own mini V-model. Thus, first, the most basic functions are implemented (minimum functionality), which then will be expanded with new ones. The main advantage of the approach is that you always have a working system, the main disadvantage is the need to redesign and rewrite the source code when the functionality of the system expands excessively.
- Evolutionary strategy. This strategy is based on partially defining the requirements of the software tool/system to be developed at the beginning of the development process. The requirements are gradually refined in successive development cycles. The result of each development cycle is usually the next version of the software tool or system to be delivered. As with the Incremental approach, the evolutionary strategy often uses prototyping. In this case, the main goal is to provide a complete understanding of the requirements.
How to Compose a Good SRS
Here are the main practices you need to follow to create a perfect SRS:
- Visualize. Using diagrams, schemes, and models is always a smart move to enrich your SRS. This will contribute to a better understanding of the processes. Visuals are irreplaceable when it comes to representing major functions and their connectivity.
- Avoid equivoque. Everything should be clear to avoid endless discussions or useless thoughts and ideas. Remember, filling in the blanks is not something your development team should do. You don’t want them to get “creative”. Ambiguous language may often cause confusion, which means it’s best to avoid subject adverbs (e.g. reasonably, mainly, approximately, etc.), synonyms, and slash-combined words (e.g. delivery/fulfillment team).
- Focus on customers.After conducting the necessary field research and comprehensive user interviews, you are supposed to have a perfect portrait of your end-user. You can even analyze how users are interacting with you on different channels especially on social media. You can directly interact with users on social media and utilize that information to improvise your product on regular intervals.This information will help you get an idea of all operations your end-users are going to perform with the product
- Critical thinking. There’s a huge number of SRS templates, thus a BA can sometimes get confused with the information to include in the doc. This is where embracing the mindset of a critical thinker might help. Explain why this requirement has to be implemented and don’t stop questioning yourself about the priorities. Each requirement comes with a timing aspect that helps prioritize it. High priority is assigned to near-term SRSs describing the core functionality of the product, midterms come with medium priority, and hypothetical requirements are low priority, however, they are still important when it comes to getting a whole picture.
- Flexibility. Your SRS must be flexible. BAs watch how it all works, get user feedback, analyze the outcome, and modify the requirement if needed.
- Traceability. An ID is assigned to each requirement so that it can be easily tracked in the documentation. Keep in mind that when reading SRS, a development team needs more context, which means that it’s highly important to crosslink the project documents with them. However, don’t forget that hyperlinks can go bad in case document folder hierarchy changes.
- History of Changes. Save it. The dev team will then be able to track down each requirement to its original, check every step and who made it, when, and why. This can help avoid any misunderstandings in the future.
- Definition dictionary. Don’t forget to clarify the terms you’re using in the SRS. You can link some of them to the outside resources and explain those you’ve come up with yourself.
Useful Requirements Management Software
Apart from Jira, you can also use Perforce Helix RM, which is a useful tool and a stand-alone module in Perfroce’s App Lifecycle Management suite. Helix RM can be integrated with Jira and is typically used by large development teams to track requirements, improve scalability, design features (has graphical tools), provide real-time collaboration, implement test case management, create recovery strategies (includes impact analysis tools), file history graphs, etc. Helix Rm can also be integrated with GitHub, Microsoft apps, Slack, Eclipse, Go2Group, Rational DOORS, and OpsHub.
If you need something more directional you can also try Pearlsto create a requirements specifications document with just one click. It has impressive team collaboration features (e.g. comments, activity notifications, features that help define project goals, etc.).
Last but not least, you can use Reqchecker, a tool that will help you check requirements coverage. This is sort of an additional assurance level that will help ensure all tests and requirements are covered. Reqchecker can work with Word, PDF, Excel, PowerPoint, XML files – feed them to the program, and it will turn them into requirements.
Each of the approaches discussed above has a certain set of characteristics and is suitable for projects of different orientations.
Both Agile and Waterfall approaches will help create almost any product. However, the trick is to determine the one that will implement the project in the most efficient and high-quality way. If you’re working on a universal project, make sure to consider time, budget, team qualification, and other criteria you find important.
The Agile approach requires a high level of professionalism from the team and is ideal for startups and advanced niches. The Waterfall approach is most often used in construction, investment, etc.
When choosing an approach, examine their strengths and weak spots, consider expert advice and determine a set of requirements for the project. The choice will then be much easier. Some developers believe that one project can optimally combine Agile and Waterfall approaches.
Remember that when making a decision in favor of one or another method, the main goal is to create a quality project that will be able to solve any set tasks.
Development teams are constantly discovering better methods of software development by developing independently and helping others to do so.
Make sure you remember the following things:
- People and interaction are more important than processes and tools;
- A working product is more important than comprehensive documentation;
- Cooperation with customers is more important than contract negotiations;
- Agility and flexibility are more important than sticking to the initial plan.
Whatever business project you want to implement and whatever development method you will choose, keep in mind that while it’s highly important to do what’s on the right (in the list above), it’s still more valuable to focus on what’s on the left.