How smartphone users assess the value/risk trade-off of apps: An observational study

The rapid and worldwide diffusion of applications for smartphones (apps hereafter) has produced a complex ecosystem composed by users, apps, developers and vendors with sometimes contrasting and sometimes matching interests. In the literature, this ecosystem has been investigated from multiple perspectives with different kinds of empirical approaches, however some crucial dimensions are still unexplored. In this paper we adopt the perspective of Requirements Engineering. We are interested in collecting empirical observations on users' perception of the risks associated to apps when they decide about which app to select and install on their smartphone. Which apps' requirements do users consider? How do they evaluate them with respect to benefits, security and privacy risks? How users decide about this is still unclear. We think that relevant variables and underlying dynamics must be identified before we can successfully conduct large-scale controlled experiments, as it is already done in other fields of software engineering. This paper presents the design of an observational study proposed to explore how users assess features and costs/risks when installing apps. The experimental design is then validated and adopted in a feasibility study with a limited set of participants. Preliminary findings are summarised in a set of observations and then discussed in terms of their potential impacts on the app ecosystem.