Functional requirements describe what software does, whereas non-functional requirements capture the quality and constraints of the software (such as performance, security or fault-tolerance). For example, "Provide the user with a line chart of monthly sales" is a functional requirement. Providing the chart in less than one second, on the other hand, is a non-functional requirement.
Functional requirements are often gathered through interviews with clients/end users and written down in text format. This typically results in long and dry documents that are practically impossible to review and comprehend.
Bring Your Concepts to Life
A fresh and lightweight approach to documenting and discussing functional requirements are "wireframes." Wireframes are rough illustrations of an application's user interface. Much like blueprints for a house, wireframes provide layout and navigation structures, without getting into design details like colors or font types. They allow all stakeholders to focus on what the application does, not what it looks like.
A Picture is Worth a Thousand Words
The most important strength of a wireframe is that it makes abstract concepts tangible. A wireframe model of the application's screens allows everyone to grasp how the application will work and if there's something missing or incorrect in the design. Users are much more likely to comment on a sketched user interface than on a textual description of a use case. This makes wireframes great communication tools that facilitate discussion between developers and business users -- even, or especially, during workshops.
A Good Tool is Half the Job
Although it's possible to sketch wireframes with nothing more than a sheet of paper and a pencil, using a dedicated wireframing tool like PowerMockup has some significant benefits:
- It provides a rich set of user interface elements that can easily be added to a wireframe
- Wireframe designs can be saved and archived
- It's easy to exchange wireframes with clients and co-workers
PowerMockup builds on top of PowerPoint, which makes it very easy to use, even for non-technical individuals. Feel free to give PowerMockup a try and download the free trial version. You and your clients will love it!