Guidelines for the design of privacy management tools for smartphone devices

Smartphones are nowadays deeply integrated in people’s everyday lives. Their popularity is in large part due to the availablity of third-party applications, often available without up-front costs, which rely on behavioural advertising as their source of revenue. However, because such devices are always with users, they expose individuals to the ubiquitous tracking of personal information by apps’ third parties, a phenomenon known as data leakage.

A Privacy Management Tool (PMT) is a type of privacy-enhancing technology intended to raise awareness and improve users’ choices regarding the privacy trade-offs that underpin the use of smartphone apps. Such tools seek to address weaknesses indicated by research which shows that while data leakage represents an acknowledged source of concern for users, the privacy information and control tools currently available on smartphones fail to support them in making informed decisions about privacy.

In order to support further development of such technology this research investigated the experience of users with a privacy management app to devise design recommendations. The provision of guidelines to help designers improve the effectiveness and user experience of such tools represents a current knowledge gap that has not been addressed in previous work.

The research began with a systematic literature review which addressed privacy issues related to apps and smartphone devices, and factors that prevent users from making informed decisions when managing privacy settings. It confirmed that apps can collect a wide range of personally identifiable information and sensitive behaviour information which is used by behavioural advertising companies to uniquely identify and track users across different applications and devices for profiling purposes.

The review also indicated that the lack of awareness concerning privacy threats, the complexity of the decision-making faced by users, and the fact that privacy is often a secondary order of concern for users are the most important factors that make privacy hard to manage on smartphones.

A user study was conducted to investigate the participants’ personal perception of privacy, and their expectations and opinions toward the privacy management app. The outcome of this study confirmed and further extended the findings from the body of publications addressed in the literature review, and led to the identification of an initial set of twenty-two design guidelines aimed at improving the effectiveness and user experience of PMTs for smartphone devices. These guidelines encompassed the communication of privacy information, the management of privacy settings as well as the awareness and feelings elicited through the use of such tools.

The proposed guidelines were further evaluated through the feedback of five experts from both industry and academia whose professional backgrounds included Human-Computer Interaction (HCI), user experience and mobile privacy. The review process was supported through a set of high-fidelity wireframe prototypes, whose design was informed by a design space that was developed as part of this research. Eighteen of the initial twenty-two guidelines were judged to be appropriate in informing the design process of PMTs for smartphone devices. Furthermore, helping users to balance the valued functionality of apps with privacy while requiring the least effort and avoiding the use of technical jargon were regarded by experts as the most critical guidelines.

Findings from the expert evaluation showed that additional effort is required to offer recommendations to:

• improve the trustworthiness of privacy information;

• find a balance between the salience of the tool and the risk of eliciting annoyance;

• enhance transparency of the data flow;

• foster acceptance of automatic decisions made on behalf of the user;

In addition, further work is required to optimise the way the guidelines are conveyed to design teams.