Tools for Achieving Usable Ex Post Transparency: A Survey <s> 1) EFFECTIVENESS AND EFFICIENCY <s> The work presented in this paper introduces the concept of On-line Interactive (OI) privacy feature which is defined as any on-line interactive tool, component or user-interface that creates privacy awareness and supports users in understanding their on-line privacy risks. These features have been developed as an interactive social translucence map that discloses the flow of personal information, a privacy enquiry for a direct chat about users' privacy concerns and a discussion forum presenting users' privacy concerns using their language in an interactive FAQ format. The paper presents an evaluation of a prototype of this set of embedded OI privacy features. The field study presented evaluates the prototype's usability and its effect on users' privacy awareness, understanding and attitude. 100 participants took part in the study and were drawn from groups of experienced and less experienced users. Both quantitative and qualitative data collection methods were used. Findings suggest that OI privacy features increase users' privacy awareness and encourage users to find out more about the uses of their personal data. However, users' ICT skills and Internet experience significantly influence whether a feature is favoured or otherwise. In general, it is concluded that privacy features are very much welcomed and necessary to empower users to manage their privacy concerns but some groups need to be further supported by social and institutional privacy management processes. <s> BIB001 </s> Tools for Achieving Usable Ex Post Transparency: A Survey <s> 1) EFFECTIVENESS AND EFFICIENCY <s> A large body of research has focused on disclosure policies for controlling information release in social sharing (e.g., location-based) applications. However, less work has considered how exposed these policies actually leave users; i.e., to what extent are disclosures in compliance with these policies actually being made? For instance, consider a disclosure policy granting Alice's coworkers access to her location during work hours. Alice might feel that this policy appropriately controls her exposure, but may feel differently if she learned that her boss was accessing her location every 5 minutes. In addition to specifying who has access to personal information, users need a way to quantify, interpret, and control the extent to which this data is shared. We propose and evaluate an intuitive mechanism for summarizing and controlling a user's exposure on smartphone-based platforms. Our approach uses the visual metaphor of eyes appearing and growing in size on the home screen; the rate at which these eyes grow depends on the number of accesses granted for a user's location, and the type of person (e.g., family vs. friend) making these accesses. This approach gives users an accurate and ambient sense of their exposure and helps them take actions to limit their exposure, all without explicitly identifying the social contacts making requests. Through two systematic user studies (N = 43,41) we show that our interface is indeed effective at summarizing complex exposure information and provides comparable information to a more cumbersome interface presenting more detailed information. <s> BIB002 </s> Tools for Achieving Usable Ex Post Transparency: A Survey <s> 1) EFFECTIVENESS AND EFFICIENCY <s> Personal and contextual information are increasingly shared via mobile social networks. Users' locations, activities and their co-presence can be shared easily with online "friends", as their smartphones already access such information from embedded sensors and storage. Yet, people usually exhibit selective sharing behavior depending on contextual attributes, thus showing that privacy, utility, and usability are paramount to the success of such online services. In this paper, we present SPISM, a novel information-sharing system that decides (semi-)automatically whether to share information with others, whenever they request it, and at what granularity. Based on active machine learning and context, SPISM adapts to each user's behavior and it predicts the level of detail for each sharing decision, without revealing any personal information to a third-party. Based on a personalized survey about information sharing involving 70 participants, our results provide insight into the most influential features behind a sharing decision. Moreover, we investigate the reasons for the users' decisions and their confidence in them. We show that SPISM outperforms other kinds of global and individual policies, by achieving up to 90% of correct decisions. <s> BIB003 </s> Tools for Achieving Usable Ex Post Transparency: A Survey <s> 1) EFFECTIVENESS AND EFFICIENCY <s> Location-Based Mobile Service (LBMS) is one of the most popular smartphone services. LBMS enables people to more easily connect with each other and analyze the aspects of their lives. However, sharing location data can leak people's privacy. We present PDVLoc, a controlled location data-sharing framework based on selectively sharing data through a Personal Data Vault (PDV). A PDV is a privacy architecture in which individuals retain ownership of their data. Data are routinely filtered before being shared with content-service providers, and users or data custodian services can participate in making controlled data-sharing decisions. Introducing PDVLoc gives users flexible and granular access control over their location data. We have implemented a prototype of PDVLoc and evaluated it using real location-sharing social networking applications, Google Latitude and Foursquare. Our user study of 19 participants over 20 days shows that most users find that PDVLoc is useful to manage and control their location data, and are willing to continue using PDVLoc. <s> BIB004 </s> Tools for Achieving Usable Ex Post Transparency: A Survey <s> 1) EFFECTIVENESS AND EFFICIENCY <s> This technical report documents the procedure of a literature review conducted on usable ex post-transparency enhancing tools (TETs). The review of scientific literature serves the purpose of provi ... <s> BIB005
Stipulated ISO usability principles of effectiveness BIB005 and efficiency BIB001  seek to provide conclusive measures of the usability of interaction systems. ISO 16982  specifies various methods for assessing the usability of HCI systems. Methods such as observation, performance measurements, questionnaires and interviews can either be used solely or jointly to assess whether and to what extend an interactive system is actually usable by the respective user group. They allow for qualitative as well as quantitative analysis of the artifacts evaluated. Individualisation  of TETs is considered desirable, the actual extent of its applicability and ultimate benefit for the user depending largely on the type and complexity of the application. Flexibility in terms of individualising the workflow associated with completing a task might lead to improved effectiveness and efficiency by adapting to the user's actual requirements and level of expertise. Following a qualitative evaluation approach, Abdullah et al.  state that the participants of the user study felt that the TET effectively achieved its intended goal. In contrast, Schlegel et al. BIB002 rely on a game-based approach to elicit the effectiveness of their notification mechanism and UI quantitatively. The authors state that the TET proved to inform the participants of their user study effectively and meaningfully, and argue that their approach is easier to use than TETs that rely on the retrospective analysis of access logs. Bier et al.  use questionnaires in the form of a System Usability Scale and a User Experience Questionnaire. The authors provide numerical and graphical representations of their results that reflect the usability of their TET in terms of various aspects covered by the questionnaires. The user study conducted by Bilogrevic et al. BIB003 relies on customised questionnaires, some of whose follow-up questions depend on answers given previously. The authors present and discuss the results in numerical and graphical form, and relate it to the capabilities of semi-automatic decision-making on part of their machine learning algorithm. Mun et al. BIB004 evaluated the effectiveness of the policy recommender of their TET by monitoring the number of participants in their user study that adapted their settings after being notified by the tool. They observed that the number of users who changed their settings after being notified declined over time and concluded that BIB005 Effective (adjective): ''Successful in producing a desired or intended result.''  25 Efficient (adjective): ''Preventing the wasteful use of a particular resource.''  their recommendations effectively helped them to establish settings that met their personal requirements.