As a CMMI Consultant, during CMMI Consulting assignment, when handling requirements analysis process, what is the focus that you should create on non-functional requirements? What are software non-functional requirements?

CMMI FAQ 0

13th October, 2014

Non-functional requirements are requirements which are not stated. They are also known as implicit or latent requirements. To use Professor Kano’s terminology, the non-functional requirements are the dis-satisfiers. That is the reason why CMMI Consultants should handle the non-functional requirements with a sharper focus during a CMMI Consulting assignment. In software terms, non-functional requirements are the ones which describe how the software will perform and places a constraint on the functional requirements.

Let us take an example of modern online banking systems which require OTP (One Time Password) to be sent to user’s registered mobile number for login in to the online system. Here sending OTP for login validation to user’s mobile is the functional requirement while sending the OTP within 15 seconds of the user request can be a non-functional requirement.

CMMI Consultants should add a guideline for non-functional requirements when they are developing the process for requirement for the client during a CMMI Consulting assignment.

Generally, non-functional requirements are not given by the client and are not evident from the existing system study and hence are to be determined by after careful analysis and by experience. These requirements are property of a product or service by which its quality will be judged. Some example of quality attributes are timeliness, throughput, responsiveness, security, modifiability, reliability, and usability. They have a significant influence on the architecture of the software.

CMMI Consultants will be adding a lot of value to the client during a CMMI Consulting assignment if they bring this kind of focus on the non-functional requirements.