Elicitation and Documentation of Non-Functional Requirements for Sociotechnical Systems

Abstract

This chapter describes how non-functional requirements (NFR) can be elicited and documented in the context of sociotechnical systems. An approach is presented based on use cases and on quality models derived from ISO 9126, as well as general problems and challenges when working with NFR. Requirements in general and NFR in particular are subjective, have many stakeholders and are often conflicting. The approach presented includes processes for prioritizing quality attributes that are important to a specific context, eliciting NFR, and identification and analysis of dependencies among the NFR. The aim is to provide an experience-based approach that facilitates efficient and effective elicitation and documentation of NFR. Having a structured method that aims at providing measurable, traceable, and focused requirements rather than having ad-hoc and ambiguous ones achieves this. The approach uses use cases as the main technique, though the general principle of having a structured and experience-based process is applicable to other techniques as well.