TITLE: COMMUNICATION-MINDED VISUALIZATION: A CALL TO ACTION. AUTHOR(S): F. B. Viégas, and M. Wattenberg

TITLE: COMMUNICATION-MINDED VISUALIZATION: A CALL TO ACTION AUTHOR(S): F. B. Viégas, and M. Wattenberg ABSTRACT: Visualization is traditionally viewed as an efficient way of transferring a large amount of information from a database into an individual's head. As a result, researchers have largely focused on techniques that improve the display of datasets for a single user. This paper proposes a new perspective, communication-minded visualization (CMV), which recognizes that data analysis is often a process involving intense communication among various stakeholders. These communication processes may occur synchronously or asynchronously, in collocated or remote settings. Drawing upon examples of existing ad hoc communication around visualization as well as theory from the field of computer-supported cooperative work, we lay out a series of a research questions and design hypotheses for CMV. 1

I) INTRODUCTION In 2003, the first author created a a software tool to visualize individuals email archives (Viégas et al., 2004). The visualization was directed at the owners of the archives and, given the personal nature of the data, it was assumed users would only view them alone. Indeed, when running a study on the system, the experimenters carefully explained to participants that no other person would have access to the visualizations. Yet as soon as users were given the applications they began finding ways to share the images. Users mailed screen shots to friends and family and called friends to sit with them to look at the visualizations together. This sharing prompted deep reminiscing and long conversations about events in users lives, which they considered an important benefit of the system. In 2005, the second author created the NameVoyager, a web-based visualization of historical data on baby name popularity (Wattenberg, 2005). The NameVoyager was designed to help expectant parents find names as well as to encourage individual exploration of the data. As it turned out, the data was explored but not just by individuals. Visitors to the site started engaging in deep conversation about their findings in discussion forums and blog comments, collectively identifying trends and anomalies and forming conjectures about the data. Communication-Minded Visualization Both of these accounts point to an unexpectedly powerful role for data visualization: that of communication enabler. While not specifically designed for communication, the applications above created rich opportunities for users to engage of discussions about the data being displayed. Inspired by these experiences, this paper introduces the concept of communication-minded visualization (CMV), meaning visualizations designed to support communication and collaborative analysis. Our emphasis is on the design of the user experience rather than technical implementation challenges. Design for communication is essential because users do not interact with visualizations solely to gain personal insights. An insight that matters will generally have to be communicated to others. As (Johnson et al., 2006) points out, visualization exists in connection with many other disciplines. To harness the power of visualization as a working tool for interdisciplinary teams, designers need to pay close attention to how visualization affects and enables the communication of discoveries and the discussion of ideas within multiple contexts. As in the examples above, communication of visualization findings usually happens through a series of ad-hoc practices, ranging from the all-pervasive screen shot to elaborate narrated videos. Also ubiquitous is the practice of leaning over someone s shoulder to see what is happening on their monitor. It is not uncommon to have up to six viewers looking at the same visualization screen as one person interacts with the data (L. Bauerle, personal communication, January 10, 2006). In presentation settings, users will project screen shots or even videos of a visualization. In certain settings, such as conference presentations for instance, video sequences have become more common as a way of making interaction and transition techniques easily understandable to viewers. Finally, printouts are used to share analysis and findings. The Need for New Ideas Unfortunately, ad hoc sharing practices all suffer from serious drawbacks. Most visualizations rely on interaction and are far less effective in screenshot or printed form. For example many popular visualizations, such as the SmartMoney Map of the Market (Wattenberg, 1999), use tooltips to label small items and so become partially illegible in screenshot form. For applications that use three dimensions, removing the possibility of motion means that the viewer has lost one 2

of the strongest depth cues (Ware, 2000). Videos can be disorienting and difficult to understand, since it can be hard to follow what actions the user is taking or know where to look onscreen. Aside from basic legibility considerations, an inability to drill down into details (whether because the user is watching a canned video or a screenshot) may reduce the credibility of an analysis. As a result, ad hoc sharing of non-interactive versions of a visualization is an unsatisfactory solution. Even though communication about and around visualization programs abounds in the real world, the ability to easily capture and communicate visualization interaction and discovery processes has received little attention from the research community. Although some commercial products have started to explore CMV-style interaction, a theoretical framework with which to think about CMV would help ground enquiry in this area as well as encourage the emergence of a community of interest. Such a framework would lay out the range of issues in the area, associate this topic to related research areas, and provide initial guidelines for CMV design and evaluation. This paper attempts to provide a preliminary version of this framework. First, we describe existing systems a research prototype and commercially available products that address different communication needs in visualization. Second, we highlight established research areas whose concerns are related to the ones in CMV. We point out the relevant topics in these areas and how these issues emerge in CMV. Finally, we outline proposals for the design and evaluation of applications. II) EXISTING SYSTEMS Designers have not completely ignored the role of communication and group usage in visualizations. It is worthwhile discussing some systems that to some extent already embody CMV. Existing applications range from large projects focused on collaborative activity to small research prototypes where CMV is just once concern of many. The PhotoMesa project (Bederson, 2001) is an image browser whose interface was designed for multiple collocated viewers. Inspired by the desire to have his two-year-old daughter watch him browse without getting lost, Bederson set a design goal that all viewers should be able to easily follow what the person interacting with the tool was doing. To ensure that sequences of navigational inputs and outputs were obvious to audience members, the PhotoMesa employs zooming and highlighting to call attention to mouse actions and make transitions comprehensible. A much larger system is CoMotion, from Maya Viz (http://www.mayaviz.com), a commercially available product that allows users to synchronously and remotely share visual data analysis tasks. In CoMotion a user opens a shared window that provides a shared view of the visualization tools in the application. Users can take turns interacting with the data in the shared view, chatting via instant messaging The CoMotion architecture led to an application for the US military called Command Post of the Future, allows the members of a command unit to share information through a collaborative visualization application [Figure 1]. In addition to a large visualization screen that is the focal point of the command room, every user their own computer running a copy of the visualization. Individual users can manipulate and annotate maps with the annotations immediately showing up on all other users screens and speeding up the spread of information. The general who deployed the system in Iraq in 2004 credits the application with providing him and subordinate commanders with the best level of insight and situational awareness in his 30-year career (Roth, 2004). 3

Since the mid-1990s (Anupam et al, 1994), several research projects have explored synchronous networked usage of scientific visualization under the rubric of collaborative visualization. Collaborative visualization systems have become important data exploration tools in a range of scientific fields from medical diagnosis (Chui & Heng, 2001) to archaeological excavations (Benko, 2004). The concerns of this field have primarily been related to the technical problem of faithfully replicating one user s experience for another at different network location. (Brodlie et al., 2004) provides an excellent survey of the state of the art. Visualization sharing can also happen asynchronously. DiscussionSite Posters by Spotfire, Inc. (http://www.spotfire.com), is the only system the authors of this paper could find which has been designed specifically to support asynchronous communication about and around visualizations. The application is a thin, Web-based client that allows users to capture interactive snapshots of data analyses. All analytic parameters can be shared, allowing a user to pass a saved poster to a co-worker, who in turn can refine the analysis [Figure 2]. Users can make notes and set visualization bookmarks (pointers to a specific state of the visualization). The notes are similar to message threads and allow any researcher to see comments made by others who have looked at the results. DecisionSite Posters can also be sent using regular e-mail; a recipient of a poster may then view and interact with the poster via a web browser and even can follow the steps the original researcher took. DiscussionSite Posters was launched in January of 2002 and has seen a slow but steady rate of adoption. In an interview with the authors of this paper (L. Bauerle, personal communication, January 10, 2006), the company said the product was created in response to customer interest in support for sharing and collaboration. So far users have been utilizing the communication capabilities in DiscussionSite Posters in an unexpected way. Instead of engaging in deeply nested threaded conversations in the conversation panel, as envisioned by the designers of the system, users have largely been building presentations of findings to share with others. The ability to create pointers into the visualization that are accompanied by commentary provides an easy way to choreograph a step-by-step presentation. Having such paths coupled with the fullfledged visualization makes it easy for viewers to take advantage of the directed view of the data but, when desired, break off to freely explore the visualization. The three systems discussed above illustrate fairly different communication scenarios around visualization applications. Whereas DecisionSite Posters is designed for asynchronous, remote communication of visualization findings, PhotoMesa is intended for live, collocated sharing of visual materials. CoMotion, on the other hand, is an application for synchronous communication of users who are not collocated. Though far from exhaustive, these examples begin to illustrate a variety of CMV scenarios The next section attempts to situate this diversity of communication settings under a unifying theoretical framework. III) THEORY CMV poses fundamentally new problems for visualization designers. An application that supports communication and collaboration has all the legibility, perceptual, and layout challenges of regular visualizations, supplemented by a host of new difficulties arising from their direct involvement in group communication practices. Of course these communication challenges are not limited to visualization programs alone. Group communication difficulties have been investigated at length in established research areas such as Computer Supported Cooperative 4

Work (CSCW). This section discusses a set of principles that are relevant to the topic of visualization as communication artifact. Time and Place One simple application of existing theory from CSCW is in finding the structure of the CMV design space. A good structure should ideally produce an organized view of existing systems while highlighting areas which have been underexplored. We believe Johansen s well-known time/space matrix (Johansen, 1988; see also Brodlie et al., 2004) does both [Figure 3]. The matrix posits two independent dimensions on which systems may differ, related to space and time. In some cases people use the system synchronously (same time) and in other cases they communicate asynchronously (interacting at different times). Orthogonal to time is space: usage can take place at a single location (same place) or at several different places. The second time/space matrix in Figure 4 lists research projects and commercial products that populate the four different quadrants produced by the two dimension [Figure 4]. The matrix is a helpful way to organize a diverse set of systems. Perhaps more important, Figure 4 makes clear that there is a neglected area. Synchronous collaborative scenarios have been much more widely explored than asynchronous communication around visualizations. Except for DecisionSite Posters, there has been virtually no work done in this area; neither in research nor in industry. We believe that asynchronous communication of visualization-driven insights is a key aspect of CMV and an important research topic. As global usage of email attests, lightweight, asynchronous communication is a ubiquitous and, therefore, powerful flavor of computer mediated communication. By disregarding asynchronous communication of visualization discoveries and processes, the research community is missing an opportunity to make important contributions to visualization research. Obstacles to Adoption There is extensive literature in the field of CSCW addressing the adoption of new groupware applications in organizations and the obstacles usually faced by this kind of software. Such work raises practical concerns for technology in real-world scenarios, ranging from social processes of communication to the political agendas that different actors might have in a group. An excellent survey of these concerns is laid out in (Grudin, 1994). We draw on Grudin s contribution to draft guidelines for CMV: 1 1) Balance of work and benefit: communication-minded visualization should strive not to significantly increase the level of additional work for individuals who do not perceive a direct benefit from the use of the application. Example: There are likely to be different kinds of users that interact with a CMV program. For instance, some users may take full advantage of the visual analysis and communication capabilities of the application whereas others may use the program simply for information viewing (which is a task that could easily be accomplished using some other program with which the user is already familiars). It is important that there is 1 Whereas Grudin listed eight challenges for developers of groupware, we have chosen four of these items to establish guidelines for CMV. The other four challenges were either integrated in the guidelines we created or did not seem relevant to our discussion here. These challenges are: - exception handling - difficulty of evaluation (covered in the section entitled proposals for evaluation ) - failure of intuition - the adoption process (included in the critical mass guideline) 5

no additional work for the viewer type user to utilize the CMV application. The Spotfire DecisionSite Posters provide a good example of this principle, since a particular visualization may be shared with a viewer who can see it without installing any special software. 2) Critical mass: the advantage of using communication-minded visualization has to be clear to individuals in order to enlist critical mass adoption. Note that since Grudin s survey the World Wide Web has exploded in popularity, providing an important avenue for amplifying usage once critical mass has been reached. Example: The NameVoyager provided a clear benefit to expectant parents. It has been suggested (Wattenberg, 2005) that other types of users saw benefits as well: a chance to socialize, explore, or just cause trouble. Once an initial core of people the critical mass began discussing the web site on their blogs, usage soared. The experience with the NameVoyager suggests that it is worth taking different roles into account, and that the Web can be a powerful force for pushing adoption by a sufficiently large group of people. Note that in The Social Life of Information, John Seely Brown and Paul Duguid argue that much of the value of real-world processes and tools is derived from the social context that surrounds them (Brown & Duguid, 2000). As the examples of the NameVoyager and Social Network Fragments suggest, data visualization has the potential to generate contextual social activity. True to the hypothesis of (Wattenberg, 2005), the discussions surrounding the NameVoyager contain a huge amount of detailed statistical analysis that greatly enhances the value of the data contained in the visualization itself. 3) Support of social processes: CMV should attempt to complement established social processes as much as possible so as not to disrupt existing practices and demotivate users crucial to its success. A classic cautionary tale is of a company that installed a new voice mail system. When the CEO called his assistant only to receive a canned message with confusing instructions, he decided on the spot to uninstall the entire system, arguing that This is not the way to treat people (Sproull & Kiesler, 91; p. 1). Example: For instance, if email is the main way through which a group of people communicates, it makes sense for the visualization application to be integrated with email at some level the entire application need not work within email, but email should be part of how users communicate about the visualization without having to switch contexts. Few visualization applications work well in the context of email, for example, despite the vast amount of collaboration that occurs in that medium. Users of visualization tools are often reduced to sending screenshots or even elaborate textual directions for what to look at. An elegant exception is current web-based mapping programs, such as Google Maps (http://maps.google.com) or MapQuest (http://www.mapquest.com). A combination of location and zoom level can be bookmarked through an ordinary URL, which is easily sent via email or instant messaging. 4) Unobtrusive accessibility: Features that support group processes may be used relatively infrequently, so CMV should be seamlessly integrated with heavily used features. Example: The emergence of CMV does not meant that users will stop conducting visual analysis on their own and start exploring visualizations in groups all the time. Instead, CMV should be seen as an additional option for doing data analysis. As such, it is crucial that these applications be well integrated to the environments where users already carry out most of their data exploration individually, namely, single-user applications. 6

At a technological level, the rigidity of many data visualization applications makes the transition to shared use highly obtrusive. Visualization environments are often carefully tuned for a specific, highly structured type of data. A treemap program, such as the University of Maryland s Treemap 4.0 (http://www.cs.umd.edu/hcil/treemap/doc4.0/toc.html) is beautifully optimized for a certain type of hierarchical data, but does not allow users to place annotations on the display. It is impossible, for example, to draw an arrow between two rectangles and add a label saying, compare these two items. This problem is not specific to visualizations, but is found in many data-centric applications. (Consider the rigidity of a relational database.) An important exception can be found in spreadsheet programs such as Microsoft Excel (http://office.microsoft.com/excel). Spreadsheets can easily handle notes as well as raw data since the user may simply write text into any cell. It is common to see users adding notes in the cells surrounding raw data, perhaps explaining their methodology in computing certain cells or pointing out the existence of strange data points. A similar technique is to use color to guide the reader s attention to important sections (Nardi, 1993). This type of marginal note-taking encourages the informal exchange of information that Brown & Duguid assert is critical for a well-functioning organization. Achieving the communicative flexibility of a spreadsheet may therefore be a helpful goal for designing CMV tools. Social Visualization A third potential source of theoretical insight is the field of social visualization. This line of investigation concerns the visualization of social information for social purposes (Donath et al., 1999), and is exemplified by such systems as Visual Who (Donath, 1995), Chat Circles (Viégas & Donath 1999) and Babble (Erickson et al., 1999). While communication is central to both social visualization and CMV, the two require different approaches. CMV is largely concerned with shared understanding and reasoning about a given data set, rather than issues of identity, reputation, and emotionally nuanced expression. Moreover, CMV applies to the analysis of any type of data, rather than specifically social information. Nonetheless, because CMV will typically involve social activity on the part of users, some of the theory of social visualization is worth bringing to bear on the problem. In particular, as we discuss in the next section, the concept of social translucence (Erickson et al., 1999) is particularly relevant. IV) DESIGN PROPOSALS AND RESEARCH DIRECTIONS Sharing and communicating around visualizations raises interesting design considerations, and suggests new areas for investigation. As previously described in this paper, users typically share visualizations by distributing images via screen shots, printouts, etc. We call this kind of sharing shallow because it is limited to the duplication of pixels instead of data. Deep sharing, on the other hand, refers to sharing data as well as pixels. To date, deep sharing has taken place mostly in synchronous applications consider, for instance, Collaborative Visualization projects where every user has access to a fully interactive copy of the visualization whereas asynchronous scenarios have been relegated to shallow sharing. We believe that intelligently sharing visualizations asynchronously that is, with annotations and tailored playback capabilities poses an important challenge for developers. 7

Taking the time/place matrix as a framework for organizing the design proposals in this section, we offer suggestions for deep sharing whenever appropriate. 1) Same time / same place Visible inputs, animated transitions It is extremely common for a small group of people to analyze data together, hunched over a single computer screen. This can be awkward; watching someone else operate a computer can be irritating, much like watching someone else to use a remote control for a TV. One reason is that changes in view appear abruptly and unexpectedly, and it can be hard for a viewer to follow what the active user is doing. The classification of spectator interfaces by Reeves et al (Reeves et al., 2005) is helpful here: they suggest that for the most understandable spectator interface, both the actions taken by the active user and the effects they generate should be easily visible. As described in (Wattenberg, 2005), a natural hypothesis is that visualizations should have as expressive an interface as possible. For example, animated transitions might be nice to have for a single user, but may be critical for a viewer to maintain a sense of orientation. This was the hypothesis used in the design of PhotoMesa (Bederson, 2001). Similarly, changes to the widgets that control a visualization should be clearly visible, and keyboard shortcuts may need to be accompanied by visible redundant cues. Note that there may be limits to the desirability of expressiveness, especially as it relates to data rather than user actions. (Erickson et al, 1999) argues for social translucence, suggesting that total transparency is undesirable in some situations. In the case of visualization, there are several scenarios where it could be better to show less information rather than more. For instance, a user may wish to share a visualization of an email inbox, but with the proviso that all names are anonymized. With a deep sharing approach, it may be possible to implement privacy filters that protect sensitive data. 2) Same time / different place Building common ground: pointing If two users are working synchronously but remotely, they also need an expressive interface. They face another critical issue as well: how to point. When two people are working at the same computer, it is common to see them pointing to different parts of the screen. Pointing is a problem for other kinds of synchronous remote work, but it can be especially acute for the unstructured displays of a visualization tool. With a spreadsheet it is easy to say, Look at cell E3, but with a typical graph layout tool it may be very difficult to verbally specify a particular node. One solution is to allow one person to move a cursor on the other s screen, or to allow drawing of annotations. A more sophisticated idea in line with deep sharing is to enable complex types of pointing that are data aware. For example, in working with a treemap it would be natural to want to point out a particular tree node and its set of descendants. One could imagine an interface where a user right-clicks on a node to get a menu of possible highlighting options: put focus on the node, its children, all descendants, etc. 3) Different time / different place More common ground to cover Asynchronous, remote communication suffers from an even greater lack of common ground than the first two scenarios in this section. Therefore, all considerations for building common ground discussed so far apply here as well. Expressive inputs, animated transitions, and pointing mechanisms should all be taken into consideration when designing CMV tools for asynchronous, remote collaborations. 8

Playback First, if a playback feature is available, we suggest it may be desirable to allow users to edit a session, picking out only a few key frames and discarding any false starts or superfluous navigation. This implies a capability to edit sequences of usage in a visualization. On a technical level, playing back a visualization implies the ability to completely reconstruct the state of the application from some sort of token sent from one user to another. Such a token could be a pointer to a central server where information is stored, or in simple cases could itself contain all the necessary information. An important issue here, related to the challenges defined by (Grudin, 1994), is that the communication capabilities are most likely to be used when they work well with existing systems. For example, if users are passing a token to represent state, it is helpful if this is a simple text string (much like a URL) that can be transferred via email or instant messaging. In (Wattenberg, 2005) a simple example of such a scheme is discussed. Annotation Another important method of asynchronous communication is annotation. In many situations it may be helpful for users to be able to point to objects and add some sort of information. The added information may be anything from a single word to a long discussion. In non-visualization settings, simple annotations have proved powerful: consider the example of del.icio.us (http://del.icio.us), essentially an annotation service for the web. Annotations raise difficult questions. A particularly thorny one is how to handle data that changes. What should happen to an annotation, for example, when an annotated data point is deleted? As with many systems that involve group creation of meaning (software development, or the writing of Wikipedia) it may be helpful to have a versioning system. Another related design question for visualizations is whether the annotations themselves can become part of the visualization. 4) Different time / same place Getting physical The prototypical example of different-time / same-place communication is the discourse that occurs on a public display screen. All of the issues described above will likely be relevant, but there is an additional interesting design question. If the space is the same, then it makes sense to design the physical surroundings to augment the visualization. At a very simple level, it may make sense to place a printer, pens and tape at the public display, so that users can print out key frames, draw annotations, and stick them to the walls. An open question is whether there are deep sharing techniques that exploit physical space. V) PROPOSALS FOR EVALUATION It is of course important to validate the importance of the communication that surrounds visualizations. The case for CMV is promising but by no means proven. A frequent situation, as in the zooming transitions of (Bederson, 2001), is that a feature is posited to help groups yet never tested with a group. It would also be valuable to study existing deployments of visualizations such as DecisionSite Posters and CoMotion to discover exactly how often their special collaborative features are used. There has been arguably too little academic evaluation of real-world deployments of commercial systems, perhaps due to a "not invented here" syndrome on the part of researchers. Another lesson from the field of CSCW field may be that important insights can come from studying commercial products such as Microsoft Excel (Nardi, 1993). 9

The premise that the communicative aspect of data visualization is an important part of its value leads to broader questions about evaluation as well. One of the perennial problems in visualization research is the difficulty of evaluating designs. The most common paradigm for evaluation is a controlled lab study where a small number of volunteers perform carefully specified tasks. While such studies produce replicable, statistically significant numbers, there is a widespread feeling that they do not reliably test the true value of visualizations (see the recent NIH/NSF study: Johnson et al., 2006) named evaluation as one of ten grand challenges facing the field.) The CMV perspective suggests some possible approaches to this challenge. First, if the success or failure of a visualization system depends on how it lets groups collaborate and communicate, then it may make sense to perform tests on groups rather than individuals. This suggests a number of variations on current practice. Most obviously, one might simply test the performance of groups of two or more people using a visualization at once. A subtler change might be to test not only direct performance, but measures of how well a viewer follows along with a user. One might have one active user perform a series of actions on a visualization, and then test whether a viewer is able to repeat those actions. More subjective measures may be revealing as well. If a visualization has a magical or secretive interface in the classification of (Reeves et al., 2005), it may be possible that a viewer would feel that the active user is uncooperative or is hiding information. These ideas are speculative, but that is exactly the point: the CMV perspective points to a whole set of untried ideas for evaluation. It is also interesting to note that the field of CSCW has faced a similar problem: (Grudin, 1994) points to several obstacles to assessing the value of systems for collaborative work. The main culprit is the fact that the success of such a system is dependent on complex social and environmental factors. As a result, it is extremely difficult to perform a lab study that will predict performance in the wild. It is also, according to Grudin, hard to generalize from one deployment to another since so many factors may be different. Again, if a significant part of the value of visualization is its ability to catalyze discussion, then the parallel with CSCW research may not be a coincidence. It may be useful to look to CSCW for ideas on how to work around the difficulties in evaluation. Given the experience of CSCW researchers, we believe studies of visualization should include more studies of real-life deployments, with careful ethnographies to understand the surrounding environmental influences on success or failure. VI) CONCLUSION Although improvements in computing technology have caused information visualization to progress significantly with faster computers allowing for smoother graphic rendering and bigger hard drives permitting vast datasets to be stored little has been done to support the communication practices that stem from interacting with visualizations. Here we propose a new perspective to remedy this oversight: communication-minded visualization (CMV). This perspective recognizes the critical role played by asynchronous and synchronous conversations and social activity surrounding graphical data analysis. Our survey of existing techniques shows that there is a wide variety of ways that designers can encourage communication around visualizations and that there is a need for a unifying framework to understand and help focus these techniques. In several cases, such as the NameVoyager, affordances that led to social activity were inadvertent. In other cases, advanced ideas for CMV exist in commercial products and are neither widely known nor well-studied. One 10

of the goals of this paper is to point out the common themes that run through these disparate systems. One source of ideas for studying CMV comes from the area of computer-supported cooperative work. We have highlighted three theoretical constructs that we believe are especially relevant. Jonathan Grudin s work on problems in uptake of collaborative systems has natural applications to the uptake of communicative visualizations. The standard partitioning of the design space into synchronous/asynchronous and same-place/different-place proves to be helpful here as well. Finally, the ideas of Brown & Duguid on the benefits of informal social context surrounding work practices help provide justification for the value of visualizations that serve as catalysts for conversation. With these theoretical constructs in hand, we have suggested several research directions. First, in designing visualizations, we advocate a deep sharing approach, in which multiple users all have access to the full system. At the simplest level, this may mean designing expressive interfaces so that two people at the same computer can easily follow each other s actions. At a more complex level, it can mean designing systems that are bookmarkable, where the full state of the system may be specified by a URL-like token, allowing annotations and asynchronous conversations. Finally, we have offered suggests for new ways to assess visualizations. Evaluation has traditionally been difficult in this area in fact finding new ways to evaluate visualizations is listed by the NSF as a grand challenge. We believe that one reason traditional evaluation methods have been insufficient is that they do not take into account group usage, and therefore miss a significant portion of the value (and problems) present in a visualization system. ACKNOWLEDGMENTS Many people made critical suggestions in the development of the ideas in this paper. Jesse Kriss and Steve Rohall made many contributions, and conversations with John Patterson were influential as well. We also thank the many other members of CUE who have helped us polish our thoughts and who have suggested related work. BIBLIOGRAPHY 1. Anupam, V., Bajaj, C., Schikore, D., & Schikore, M. (1994). Distributed and collaborative visualization. Computer, vol. 27, no. 7, pp. 37-43. 2. Bederson, B. B. (2001). PhotoMesa: A Zoomable Image Browser Using Quantum Treemaps and Bubblemaps. UIST 2001. 3. Benko, H., Ishak, E.W., & Feiner, S. (2004). Collaborative mixed reality visualization of an archaeological excavation. The International Symposium on Mixed and Augmented Reality, ISMAR. 4. Brodlie, K. W., Duce, D. A., Gallop, J. R., Walton, J.P.R.B. & Wood, J. D. (2004). Distributed and Collaborative Visualization. Computer Graphics Forum, Volume 23, Number 2, pp 223-251. 11

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BIOGRAPHIES: Fernanda B. Viégas Research Staff Member Fernanda s research interests include visualizing social dynamics in open-source communities, exploring collaborative uses of visualization applications, and investigating online privacy as it applies to visualization. Before joining IBM, Fernanda was a graduate student at the MIT Media Lab where her research focused on visualizing the traces people leave as they interact online. Some of her projects explored email archives, newsgroup conversations, chatroom interactions, and the editing history of wiki pages. She is also the creator of the award-winning Chat Circles program, an abstract graphical interface for communicating online. Fernanda holds an M.S. and Ph.D. degrees from MIT, and a BFA from the University of Kansas, where she studied Graphic Design and Art History. Martin Wattenberg Group Manager, Researcher Martin s research interests include information visualization and its application to collaborative computing. Before joining IBM, Martin was the Director of Research and Development at SmartMoney.com, where he designed internet-based financial software. His work at SmartMoney included the groundbreaking Map of the Market, which visualizes live data on hundreds of publicly traded companies. Martin has also worked with nonfinancial data ranging from email archives to baby names. In addition he is well known for artistic data visualization, visualizing such disparate information sources as music, museum collections, and web searches. His artwork has been exhibited internationally, including at the Whitney Museum of American Art, the New Museum, and Ars Electronica. Martin holds a PhD in Mathematics from the University of California at Berkeley 14

Figures and tables: Figure 1: Above, screen shot of the Command Post of the Future tool, created by Maya Viz for the US military forces. On the left, a view of the tool being tested by multiple users in an non-military setting. Figure 2: On the right, a screen shot of SpotFire s DiscussionSite Posters tool. The tool allows users to share data analysis and comments about a given visualization asynchronously. On the left, a closeup view of the communication panel where users leave comments that can be anchored to specific states of the visualization by bookmarks. 15

Figure 3: Time/space matrix showing the range of CMV scenarios developers are likely to encounter. Figure 4: Johansen s matrix showing the distribution of projects amongst the four main time/space arrangements in CMV. Synchronous communication around visualization programs is the area most heavily populated. Asynchronous, remote CMV, on the other hand, is a practically empty area, without any academic research having been done in the topic. 16