The Implications of ‘Soft’ Requirements

Abstract

A new focus for RE is investigated as ‘soft’ requirements which extends non-functional requirements / soft goals with a collection of people-oriented phenomena: values, motivations, emotions, and other socio-political issues that may influence the requirements specification. The convergence of RE with user experience (HCI) and technology acceptance from the information systems literature is reviewed from a temporal perspective: pre-use, through initial to longer-term use. A taxonomy of soft requirements is proposed that extends non-functional requirements and soft-goal concepts to direct attention towards user characteristics and beliefs that may have implications for functional as well as system support requirements, such as training, help, explanation and trust in software. A timeline model of soft and hard (functional) requirements is presented with a focus on customization, adaptation and other soft requirements to, improve product acceptance and persuade users to take appropriate action. The paper concludes with a research agenda for soft requirements to improve the probability of system acceptance and the effectiveness of applications that aim to influence people’s decisions and behaviour in internet apps and other discretionary-use applications.