Validating non-functional requirements gathering, you are here
Requirements are the means of communication through which customers, suppliers, developers, users and regulators can agree on what is to be achieved. This broad heading covers all requirements that are derived from factors external to the system and its development process.
Teams build systems that deliver value to the user, and most of the time and effort in solution development is devoted to that. Some people refer to the relationship between requirements induced by recording satisfaction between layers as a requirements hierarchy, but in reality the many-to-many relationship forms a graph or heterarchy.
Worse, it can mean that NFR testing may be practical only on occasion or only with specialty resources or personnel. To ensure practicality and continuous use, teams often need to create reduced test suites and test data, as illustrated in Figure 7.
It may be part of the contract between the system buyer and the software developers.
Sometimes the NFR must be implemented all at once; other times the teams can take a more incremental approach. Other reasons include lack of resources, unrealistic expectations, lack of executive support, changing requirements, lack of planningetc.
Non-functional requirements often apply to the system as a whole, rather than individual system features or services. The devil is in the details. Requirements are used to test that the design or solution is acceptable.
Non-functional requirements are often more critical than individual functional requirements.
User requirements and system requirements may be defined as follows: Functional Requirements should include: