What are Non-Functional Requirements (NFR) | level (2023)

Jory MacKay

Jory is a writer, content strategist, and award-winning editor at Unsplash Book. He contributes to Inc., Fast Company, Quartz and more.

Aug 16, 2022 9 minutes read

The data shows that the inaccurate capture of requirements is one of the main reasons70% of projects fail. However, below that statistic is therealProblem: Teams focus too much on functional requirements (what the system does) and forget about non-functional aspects (ifthe system does).

Non-functional requirements ensure that you provide a good user experience and that your product performs at the level expected by your customers, customers, and stakeholders.

Unfortunately, many product teams ignore non-functional requirements (NFRs) until it's too late. Even worse, update NFRsafterBuilding your software is expensive and can break your budget.through some reports, unnecessary code and requirements rework costs companies between $400,000 and $94 million a year!

You don't have to make the same mistakes.

This guide covers what non-functional requirements are, why they are important, and how to include them in your product roadmap and sprint planning.

Jump to a section:

What are Non-Functional Requirements (NFRs)?

Non-Functional Requirements (NFRs) define “how” systems do what they do. These include properties such as performance, security, ease of maintenance,scalability, and ease of use. Essentially, they provide the appropriate checks and balances against functional requirements.

but what thatReallymean?

The functional requirements areWasyou will build This can mean a webpage, an application or an integration flow. On the surface, your product's functionality might seem like the most important focus for your team. And this is! Without working software, your users won't be able to use anything.

But functionality alone is not enough to create an attractive product.

Non-functional requirements ensure that a system or product existsthe truth isusable, offers a great customer experience, is secure and complies with legal regulations.

RNFs are essential. But they are also a matter of balance and compromise. While you don't want to forget them until it's too late, you don't want to focus either.Alsotoo much on NFRs at the expense of their cost, schedule, and resources (ieProjektmanagement Triple Constraint).

Imagine you are buying a sports car. One of his functional requirements for the car is that it has doors. Non-functional requirements would specifyifThese ports work. Are these normal old doors? Or those super cool gullwing doors you see on high-end Teslas and Mercedes?

Any choice works. But you have to decide which option gives you the best driving experience.

Top 10 types of non-functional requirements

Where most teams fail with NFRs is they focus on the obvious one or two and forget the rest.

Your team doesn't "forget" to think about performance issues or test reliability. But do you plan on localization, regulatory issues or maintenance?

A good product manager must consider all ten non-functional requirements during the processphase of development. This includes:

In reality, non-functional requirements often overlap from type to type. Therefore, only use these categories as a guide when considering NFRs for your project.

How NFRs are helping development teams

Let's put project management aside and put ourselves in the shoes of the development team.

Dealing with non-functional requirements can feel like extending your ownproject scope. Ultimately, however, they make software systems much easier to develop, deploy, and maintain. This in turn makes the developer's life much easier.

Here are the top ways NFRs make life easier for your development team:

• You help shape the architecture.Non-functional requirements help teams plan ahead and prepare their design for the future. Without strategic NFRs, developers build features on top of other features without an overarching vision to work from.
• They support performance.NFRs help developers understandhow is "good"for the system. This gives software teams a baseline performance target and ensures the system always delivers what it's supposed to.
• They reduce the time spent on errors.Specifically in terms of performance, reliability, and maintainability, NFRs help teams create high-quality code that fails less often.
• They help teams avoid rework.The added depth and richness that NFRs bring helps developers get things right the first time. This saves time in post-processing and allows developers to manage theirs more efficiently and betterbusy workload.
• They bring developers and end users closer together.Finally, well-written non-functional requirements help developersbetter understand the end user. This vision of 'if'really helps developers to build features that really meet customer expectations.

How NFRs help project managers

Back to project management and time to think more strategically about non-functional requirements. Or more specifically, what happens whenOfdon't you think about non-functional requirements as a project manager?

Something small can easily derail your project and cause you to miss your goals. Here are just some of the reasons why forgetting about non-functional requirements can make you and your project non-functional:

1. You can miss deadlines.Missing NFRs can lead to rework, bug fixes or even complete system crashes. Those minutes and hours add up and result in appointment delays because the system just isn't ready.
2. You're breaking your budget.Likewise, development time costs money, so rework will leave you footing the bill. Don't blow your project budget by missing out on a simple NFR that results in costly overtime.
3. Unsatisfied customers.Non-functional requirements ensure that you deliver exactly what the customer needs. Don't think about your NFRs and you'll ship a completely useless product while annoying your users.
4. You will inadvertently create risks.Remember those safety NFRs? When you're not looking at the big picture, you can open your project team and usersRisks they didn't even know existed!
5. Your area will crawl.Finally, if you don't properly identify the correct non-functional requirements, you will end up withOpportunist. As your scope increases, you end up doing additional work that stretches your schedules and increases your budget.

Updating non-functional requirements after building the software is expensive and can break your budget.

7 steps to include NFRs in your roadmap and planning

NFRs are clearly important. But how do you work them into yoursproduct strategy?

Here are seven easy steps to incorporate non-functional requirements into your design orproduct roadmap:

1. Make a list of quality attributes

Start by understanding what "quality" means to you and your customers.

For a specific feature or functional requirement, try to understand what the customer needs by asking yourself:

• What is important to the customer?
• What features would make the feature/product great?

If you're having trouble, try to think backwards,debatewhich would make this feature really bad.

For example:

Functional requirement:As a user, I want to go to the home page to start using the product.

What would make it great?If only it loaded really fast.

What would make it bad?If the text size was too small, you wouldn't be able to read it.

Congratulations, you've just discovered two Quality Attribute Requirements (QARs)!

If you need more information, don't be afraid to research and research the market to understand the good and bad qualities of similar products.

2. Set clear expectations for each requirement

Now that you have a better idea of ​​the quality attributes you want to offer, it's time to put some meat on the bones of your NFRs.

It's all about quantifying user expectations and turning vague words into solid, actionable statements to build your product.

Let's use the previous examples:

Remember to constantly refer to your functional requirements to understand the context and needs of the customer.

Pro tip:Keep your NFRs in your product backlog along with all your other work. A project management tool likeI plancan help you stay organized so none of your important needs (functional or otherwise) get lost.

3. Analyze the broader impact of your NFRs

No project happens in isolation. There will be many other projects, changes and roadmaps around the company.

Before you start developing, it's a good idea to step back and make sure your non-functional requirements aren't inadvertently causing problems for another part of your product or a broader IT infrastructure.

Here are some examples:

• Perfomance:Will your performance requirements consume other resources?
• Security:Do you work to the same standards as other apps?
• User friendliness:Your customer already knowsworkflowsfrom other products?
• Maintainability:Are there core processes for product updates?
• Resilience:Are there already continuity standards across the organization?

Comparing your NFRs with other project teams can at least help you identify new requirements that you haven't even thought of!

Ultimately, non-functional requirements make it easier to develop, deploy, and maintain software systems.

4. Decide on your NFR implementation approach

That's the be-all and end-all of a project manager: delivery.

Are you delivering all your NFRs at once or building them up in stages? The answer is probably a bit of both, depending on the nature of the non-functional requirement. For example:

• You don't want to take any risks.SecurityorregulateNFR, so we recommend submitting everything at once.
• On the other hand, you may be confrontedPerformanceNFR einsuser historyat a time until you reach the quality level you want.

It's all about balance here. A complete approach takes more time and makes your users wait longer for new features. However, you don't want to under-deliver and risk dissatisfying your customers with an incremental approach.

5. Include NFRs in your next sprint cycle

Excellent! Now your NFRs are ready to hit the developer's desk and come to life.

As with any user story, take your time with yoursSprintplanungand fully estimate the size of each requirement. This is to ensure that your development team can accommodate any requirement in the workload.

there are many differencesestimation methods, IncludingPokerplanung,shirt size, z3 point analysis, so choose the one that works best for you and your team.

If you're happy, put them in yoursagile project managementTool ready for developers to start working.

6. Create an NFR test plan

No new feature can really come to life without some testing. The data also confirm this. The lack of testing is one of theKey contributors to the development revamp!

Your testing plan is designed to help you discover bugs, bugs, and gaps that may cause NFR to provide a poor experience.

Here are five easy steps to create a test plan:

1. Start by analyzing the requirement you are testing.You already know everything about the requirement, so discuss it with the developers and testers so you're up to speed.
2. Design your testing strategy.Consider which areas of the NFR are most important to you, the time/resources you have, and what type of testing you want to conduct, e.g. B. Unit tests or stress tests.
3. Define your goals and pass/fail criteria.This depends on the requirement itself and any tolerances you are happy with.
4. Plan the test environment.It's always good to be prepared, so put together the right testing environment to give you the best chance of success.
5. Run, monitor and deploy.Now it's just a matter of putting the plan into action before making a deployment decision.

If you need additional help, check out ourUltimate guide to creating a test plan.

7. Assess the impact of NFRs through user surveys

It's not all over with the use of the NFR. You must monitor its effectiveness once it is in the hands of the customer.

There are so many ways to get richUser Experience Feedbackof its users, be it through surveys, interviews, A/B tests or usability evaluations.

From your user research, you will understand if the NFR landed correctly or if you and the project team need to do additional follow-up work.

What are the potential risks of non-functional requirements?

Before you rush out and add hundreds of NFRs to your product backlog, remember that they are part of a delicate balance. Too little emphasis on NFRs and you risk reworking or failing to meet user expectations. But too much emphasis and you'll blow your project budget, scope, and schedule.

As you begin adding more NFRs to your product roadmap, watch out for these common risks:

• Negative performance and usability.Remember to step back and consider your wider environment, as NFRs can negatively impact other product functionality. It's all about testing and learning to avoid problems in your wider environment.
• An ever-increasing scope.Once you start researching NFRs, it's easy to come up with hundreds of great ideas for your product. Remember to be pragmatic. Otherwise, you end up with a project scope that keeps growing.
• deprioritization. Because NFRs aren't as exciting as functional requirements, business stakeholders often want to deprioritize them. occasionallydeprioritizationhe's fine. But do this too often and you will be left with a product that just doesn't work. Again, it's all about balance.

It's time to board the NFRs

Many projects fail because they forget to consider non-functional requirements. Don't make the same mistakes and accept the NFRs as they make the difference between happy and unhappy users.

Our guide to including NFRs in your product roadmap walks you through the process from start to finish. Once you have a clear view of what's important to your users, it's important to structure your NFR deployment through discovery, planning, testing, and delivery. You take care of that in the endifYour product is just as important as how it worksWasYour product does.