What are non-functional requirements and how can they be included in the project? Data shows that improper requirements gathering is one of the main reasons for the failure of 70% of projects. However, behind these statistics lies the real problem: teams focus too much on the functional requirements (what the system does) and ignore the non-functional aspects (how the system does it).
Non-functional requirements ensure that you provide a good user experience and that your product performs at the level that customers and stakeholders expect.
Unfortunately, many product teams ignore non-functional requirements (NFRs) until it’s too late. Even worse, updating non-functional requirements after the software is built is expensive and can drain your budget.
In this guide, we’ll cover what non-functional requirements are, why they’re important, and how to incorporate them into your product roadmap and sprint planning.
What are non-functional requirements?
Non-functional requirements define “how” the systems should perform. It includes features such as performance, security, maintainability, scalability, and ease of use. Essentially, they provide appropriate checks and balances for performance requirements.
Functional requirements are what you want to build. This can mean a web page, application, or login flow. On the surface, product performance seems like the most important thing your team should focus on; And this is true! Without application software, you have nothing to offer your users.
But performance is not enough to create a compelling product.
Non-functional requirements ensure that a system or product is usable, provides a great customer experience, is secure, and complies with regulatory requirements.
Imagine you are buying a sports car. Among your functional requirements for the car is that it has a door. Non-functional requirements specify how those doors should function. Are they regular old doors? Or the super cool doors you see on Teslas and Mercedes Benz?
Any choice will be fine, But you have to decide which option gives you the best driving experience.
10 main types of non-functional requirements
The mistake most teams make when it comes to non-functional requirements is to focus on one or two obvious ones and forget about the rest.
Your team doesn’t “forget” to address test performance or reliability issues. But does it also plan for localization, regulatory issues, or maintainability?
A good product manager should consider ten non-functional requirements during the development phase, which are:
- Performance: Focuses on the speed, efficiency, and workload of the system. For example, how quickly does the system respond?
- Scalability: Ensures that the system can respond to changes in demand. For example, how will the system absorb additional resources?
- Reliability: Defines system availability and failure tolerance, for example, what is the target uptime?
- Resilience: Determines how quickly a system can recover in the event of a failure. For example, how does the reset process work?
- Security: Focuses on how to keep the system secure, store data, and respond to attacks. What are the security protocols of the site?
- Usability: Defines how systems work for the customer/end user. For example, how many clicks does it take to get to a certain location?
- Maintainability: Ensures that the system is easy to upgrade and troubleshoot. What is the format of the error report?
- Changeability: Defines how the system can be changed if necessary. For example, how can users customize certain features? How can developers tune the code?
- Localization: Defines how a system adapts to the user’s location. For example, how does the system detect and display different languages/currencies?
- Monitoring: Ensures that the system follows the rules. For example, how does this system comply with the ISO27001 standard?
3 steps to include non-functional requirements in roadmap and planning
Non-functional requirements are important. But how should we include them in our product strategy?
Here are seven simple steps to include non-functional requirements in your project or product roadmap:
1- Make a list of quality attributes
Start by understanding what “quality” means to you and the customer.
For any specific feature or functional requirement, try to understand what the customer needs by asking yourself:
- What is important to the customer?
- What features make this feature/product great?
If you’re having trouble, try brainstorming the other way around: What makes the feature bad?
For example:
Functional requirement: As a user, I want to land on the home page so I can start using the product.
What makes it great? It loads very quickly.
What makes it bad? If the text size is too small, it cannot be read.
Now you’ve discovered two Quality Attribute Requirements (QARs)!
If you need more information, don’t be afraid to do some market research to understand the pros and cons of similar products.
2- Set clear expectations for each need
Now that you have a better idea of the quality features you want to provide, it’s time to move on to completing your non-functional requirements.
It involves quantifying user expectations and turning vague words into solid, actionable statements that you can build your product around.
Let’s use the previous examples:
Previous → “That it loads very quickly.”
Next → “The page loads in less than 1 second”
The
Previous → “If the text size is too small, it cannot be read”
Next → “Text size will be 16 pixels”
Remember to constantly refer back to your functional requirements to understand the context and what the customer needs to achieve.
3. Analyze the broader impact of your non-functional requirements
No project happens in isolation. There will be many projects, changes, and roadmaps around the business.
Before you begin development, take a step back and ensure that your non-functional requirements are not inadvertently causing problems for another part of your product or wider IT infrastructure.
Here are some examples:
- Performance: Are your performance requirements draining other resources?
- Security: Are you working to the same standards as other apps?
- Usability: Is your customer already familiar with the workflows of other products?
- Maintainability: Are there central processes for updating the product?
- Flexibility: Are there standards for continuity across the business?
If nothing else, cross-checking non-functional requirements with other project teams might help identify new requirements you hadn’t even thought of!
Conclusion
Many projects fail because their managers forget to consider on it. Don’t make the same mistakes and deal with non-functional requirements because they make the difference between happy and unhappy users.
This article provides a complete guide to include non-functional requirements in the product roadmap from start to finish in this process. Once you have a clear view of what is important to your users, you should start structuring the delivery of non-functional requirements through discovery, planning, testing, and deployment. In the end, you’ll find that how your product works are just as important as what it does.
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