International Large-Scale Assessments (ILSA) have a critical role in shaping education systems around the world. They impact local and national education policy and receive much attention in the media and the public discourse. However, the public has limited access to the results and cannot learn from them. Subsequently, the media might frame the results incorrectly. The transparency of ILSA is essential to the advancement of the public discourse. It requires easy access to data together with simple analysis tools. However, the complexity of ILSA makes it hard to understand and to analyze. Open PISA tries to deal with this challenge by developing a dashboard for the Program for International Student Assessment (PISA). It aims to guide users in the analysis of the dataset. This paper describes the dashboard design and insight based on collected users' responses. It hypothesizes that full transparency of the PISA dataset might be not achievable to the entire public. Further research is needed to evaluate how dataset analysis affects users' knowledge and opinions.

Composite Indicators (CIs), are a common measurement and benchmarking tool that are used to reflect and measure multidimensional concepts such as digital divides, individual's well-being and more. Measurement iterations produce a series of time-oriented data, which stakeholders as well as the general public might be interested to interpret. Visualization of a CI is highly recommended in order to ease interpretation, and many CI websites use radial solutions to visualize CIs. Yet it is unclear how to visualize the temporal dynamics in radial diagrams. Static solutions, mapping time to small multiples might be challenging due to screen space issues. Dynamic solutions are appealing, yet, there is no clear empirical evidence on benefits of dynamic time coding in radial diagrams. In this paper, we compare static vs. dynamic time mapping using two radial CI visualization methods. The popular Radar chart technique is compared to the innovative Flower chart as used in the well-known OECD Better Life index. We compare users' performance and preferences empirically under formal task taxonomy, adjusted to CI tasks. Results indicate that in general, static time encoding was more effective than dynamic encoding. Still, an in depth analysis showed that the dynamic approach is a feasible and sometimes even better solution for important CIs tasks, leveraged by the fact that users seem to like and enjoy it.

A composite indicator (CI) is a measuring and benchmark tool used to capture multi-dimensional concepts, such as Information and Communication Technology (ICT) usage. Individual indicators are selected and combined to reflect a phenomena being measured. Visualization of a composite indicator is recommended as a tool to enable interested stakeholders, as well as the public audience, to better understand the indicator components and evolution over time. However, existing CI visualizations introduce a variety of solutions and there is a lack in CI's visualization guidelines. Radial visualizations are popular among these solutions because of CI's inherent multi-dimensionality. Although in dispute, Radar-charts are often used for CI presentation. However, no empirical evidence on Radar's effectiveness and efficiency for common CI tasks is available. In this paper, we aim to fill this gap by reporting on a controlled experiment that compares the Radar chart technique with two other radial visualization methods: Flower-charts as used in the well-known OECD Betterlife index, and Circle-charts which could be adopted for this purpose. Examples of these charts in the current context are shown in Figure 1. We evaluated these charts, showing the same data with each of the mentioned techniques applying small multiple views for different dimensions of the data. We compared users' performance and preference empirically under a formal task-taxonomy. Results indicate that the Radar chart was the least effective and least liked, while performance of the two other options were mixed and dependent on the task. Results also showed strong preference of participants toward the Flower chart. Summarizing our results, we provide specific design guidelines for composite indicator visualization. Fig. 1: Three radial solutions for composite indicator visualizations compared empirically for users' performance and preferences.

Question and answer (Q&A) sites such as Yahoo! Answers are places where users ask questions and others answer them. In this paper, we investigate predictors of answer quality through a comparative, controlled field study of responses provided across several online Q&A sites. Along with several quantitative results concerning the effects of factors such as question topic and rhetorical strategy, we present two high-level messages. First, you get what you pay for in Q&A sites. Answer quality was typically higher in Google Answers (a fee-based site) than in the free sites we studied, and paying more money for an answer led to better outcomes. Second, we find that a Q&A site's community of users contributes to its success. Yahoo! Answers, a Q&A site where anybody can answer questions, outperformed sites that depend on specific individuals to answer questions, such as library reference services.

All information exchange on the Internet -- whether through full text, controlled vocabularies, ontologies, or other mechanisms -- ultimately requires that that an information provider and seeker use the same word or symbol. In this paper, we investigate what happens when both searchers and authors are dynamically choosing terms to match the other side. With each side trying to anticipate the other, does a terminological convention ever emerge, or do searchers and providers continue to miss potential partners through mis-match of terms? We use a game-theoretic setup to frame questions, and learning theory to make predictions about whether and which term will emerge as a convention.

The asymmetry of activity in virtual communities is of great interest. While participation in the activities of virtual communities is crucial for a community's survival and development, many people prefer lurking, that is passive attention over active participation. Lurking can be measured and perhaps affected by both dispositional and situational variables. This work investigates the concept of cultural capital as situational antecedent of lurking and de-lurking (the decision to start posting after a certain amount of lurking time). Cultural capital is defined as the knowledge that enables an individual to interpret various cultural codes. The main hypothesis states that a user's cultural capital affects her level of activity in a community and her decision to de-lurk and cease to exist in very active communities because of information overload. This hypothesis is analyzed by mathematically defining a social communication network (SCN) of activities in authenticated discussion forums. We validate this model by examining the SCN using data collected in a sample of 636 online forums in Open University in Israel and 2 work based communities from IBM. The hypotheses verified here make it clear that fostering receptive participation may be as important and constructive as encouraging active contributions in online communities.

Abstract This is an empirical, experimental investigation of the value of information, as perceived through the willingness to purchase information (WTP) and the willingness to sell it (accept payment, WTA). We examined the effects of source nature: expertise versus content, and source status: copy versus exclusive original of information on the WTA–WTP ratio. In an animated computer simulation of a business game, players could maximize their profits by making choices regarding inventory and prices. Participants were offered the chance to bid for buying or selling information regarding the weather that may affect demand. We find, as hypothesized, that the subjective value of information does indeed follow the predictions of endowment effect theory. The ratio of willingness to accept to willingness to purchase (WTA–WTP) recorded for the 294 subjects resembles the ratio common for private goods, rather than the intuitively expected unity. The WTA–WTP ratios diverged from unity more often and in a more pronounced manner for information traded in the “original” form rather than as a copy of the original, although even for copies the WTA–WTP ratio is still double. The results yield a value of about three for the WTA–WTP ratio for original information whether the source is content or expertise. Copy information received a subjective value that was significantly different (lower) than original information. The implications for both online trading and online sharing of information are discussed.

This is a study of social facilitation effects in online auctions. We focus on the growth in online auctions, and the emergence of instant messaging and communication availability technologies. These two trends merge to provide a collaborative online social framework in which computer mediated communication may affect the behaviour of participants in online auctions. The interaction between buyers and sellers in traditional, face-to-face markets creates phenomena such as social facilitation, where the presence of others impacts behaviour and performance. In this study we attempt to replicate and measure social facilitation effects under the conditions of virtual presence. Does social facilitation apply to online auctions, and if so, how can it influence the design of online settings? We developed and used a simulated, Java-based Internet Dutch auction. Our findings indicate that social facilitation does indeed occur. In an experimental examination, participants improve their results and stay longer in the auction under conditions of higher virtual presence. Participants also indicate a preference for auction arrangements with higher degrees of virtual presence. Theoretically, this study contributes to the study of social facilitation, adding evidence of the effect when the presence is virtual.

This paper provides a comprehensive review of empirical research into user contributions to computer-mediated discourse in public cyber-spaces, referred to here as virtual publics. This review is used to build a systems model of such discourse. The major components of the model are i) critical mass, ii) social loafing, and iii) the collective impact of individual cognitive constraints on the processing of group messages. By drawing these three components into a single model it becomes possible to describe the shape of a “user-contributions/user-population function” after controlling for context.