Visualizing the SIMS Classroom Backchannel

Information Visualization • Fall 2005

Sarai Mitnick • smitnick at sims.berkeley.edu
Sarita Yardi • yardi at sims.berkeley.edu
Link to project page thumbnail
Link to current prototype
 
Introduction •  Related Work •  Design Process •  User Testing •  Visualizations •  Conclusions and Future Work •  Appendix •  References

 

Introduction

Project Idea

For the last year, SIMS students have engaged in online discussion on their own IRC channel. Interactions occur both inside and outside of class, when users are co-present or in separate physical environments. Conversations sometimes augment class discussion, allowing for different types of in-class participation, as well as the sharing of relevant material, URLs, etc. We are seeking to enable professors and teachers to visualize chatroom discussions in order to evaluate how successfully they are teaching and how well students are comprehending the material.
 

Project Goals

In addition to examining SIMS-specific IRC data, we have explored the benefits of such a visualization for educators wishing to understand the relation of chat activity to the classes they teach. Some courses now incorporate chat into the classroom, by creating sanctioned IRC channels for students to engage with one another. A visual analysis of log data from such discussions may prove interesting or useful for professors. While we have not created a fully-functioning tool, we have created a prototype visualization using SIMS data in order to examine the possibilities of such a tool.
 

Hypotheses

We expected to see fairly consistent daily usage patterns, with highs and lows at specific times of day. We also expected that academic events within SIMS (exams, papers assigned or due) would produce sharp peaks that fell outside of these patterns. We also anticipated that certain classes would generate more participation and higher numbers of users. We hoped to analyze these possibilities by implementing a proof of concept and performing preliminary testing to suggest that these types of results could be useful for educators. Below are some hypotheses that we used to help direct our design and user tests:
    • Implementations of the backchannel will and should vary across different contexts and domains
    • Teaching styles should take advantage of the social and educational affordances the backchannel offers
    • Chatrooms should enable teacher self-assessment
    • A backchannel should encourage social interactions and community building
    • A backchannel etiquette will need to be developed
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Related Work

Research has been done on the role of online backchannel discussions that take place among co-present participants[i] , such as attendees of an academic conference[i] This research is highly relevant and uses chat log data to draw conclusions about the role of this type of communication. However, we have found little research on the role of these discussions in the classroom setting. Many of the studies on the use of technology-mediated discussion in the classroom focus on the overall effects of multi-tasking on student performance [iii] or how technology may be incorporated to encourage discussion [iv], rather than an examination of the patterns of online discussion within the classroom setting.
 

Existing Visualizations

How do we enable a quick and intuitive response that requires little effort for a professor or teacher?
Coterie (Figure 1) and PeopleGarden (Figure 2) are examples of semantic visualization, where the meaning and relevance of the data is conveyed in the design of the visualization. Semantic visualizations will help a professor to visualize the social and academic environment in the chatroom in order to better understand how well he or she is teaching and how well the students are learning the material. Although this information could conceivably be displayed through a simple table with student names and number of contributions, we feel that a semantic visual design could be a more pleasing and desirable method for a professor to view this information. It would facilitate a quick mental depiction of the social dynamics and the material being discussed. PeopleGarden offers an interesting metaphor of life, growth, and health, through its use of flowers, petals, and gardens as visual representations. We will look to explore similar metaphorical visual icons that can be used to convey academic properties to a professor.


Coterie
Figure 1. A Coterie[xvi] display showing three simultaneous conversational threads: one related to aircraft, one about screens, and one with a comment about a previous statement’s usage. Six users are currently active, but many more are listening.

In Coterie, one can see at a glance how many people are logged into a channel. The participants are represented as colored ovals that bounce and become brighter when that person speaks. This highlights the active participants and conveys the vitality of the discussion. By visualizing presence and conversational activity, Coterie creates an environment that looks like the conversation—coherent discussions form a solid, central core and scattered chats are, well, scattered all over the place. One easily senses how populated the channel is and who are the primary participants.
 
 
PeopleGarden
Figure 2. Two PeopleGarden[v] visualizations
Left: a group with many members at different levels of participation.
Right: a group with a single dominant member.

PeopleGarden uses a flower and garden metaphor to visualize participation on a message board. Participants are each represented by a flower. The longer they have been involved, the higher the stem; the more they have posted, the more petals. Initial postings are shown in red, replies in blue. One can easily get a sense of an individual’s role as an active participant or a long-time lurker.
 
 
QueryLines
QueryLines: approximate query for visual browsing
[xiii] QueryLines approximates query techniques for searching and analyzing two-dimensional data sets such as line or scatter plots. The techniques allow users to explore a dataset by defining QueryLines: soft constraints and preferences for selecting and sorting a subset of the data. By using both preferences and soft constraints for query composition, it allows greater flexibility and expressiveness than previous visual query systems. When the user over-constrains a query, for example, a system using approximate techniques can display "near misses" to enable users to quickly and continuously refine queries.

Although the concept behind QueryLines is useful, we rejected the idea of soft constraints for our visualization because we feel that it is too complex and detailed. While a professor could certainly be capable of using a similar feature, they likely will not want the time overhead of deducing when a soft constraint query is necessary. With our goal of creating a simple and intuitive design we think it is better to have fewer visualization options as a tradeoff for a more clear visualization design.

Figure 3. Example queries for a sample dataset: (a) all the plots, (b) min and max hard constraints prune the set of exact matches, (c) an over-constrained query (i.e., no exact matches) with two soft matches, and (d) a preference, goal query.
 
 
Milestones in Time
Figure 4. The Milestones in Time: The Value of Landmarks in Retrieving Information from Personal Stores[vi] showed that users experienced a faster search time when the timeline contained landmarks than when it didn’t. Although the context of this study is slightly different, we suspect that similar trends might be seen in a classroom environment because a professor’s lecture content is still personal to him or her. This indicated to us that professors might want to overlay topical lecture information, as a type of “landmark”, onto the graph to more quickly searches for the information they are looking for.

We displayed topics in our test file using TimeSearcher, see Figure 16, as one method in which professors could quickly visualize topics. This topic is further discussed in our Conclusions and Future Work section.
 
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How should the professor select a time frame to visualize?
We want to enable dynamic querying, in which the professor can select a range of time frames with real-time feedback in the visualization. We want to enable the following components, as described in Professor Marti Heart's Dynamic Querying lecture:
    • Visual presentation of query's components
    • Visual presentation of results
    • Rapid, incremental, and reversible control
    • Selection by pointing, not typing
    • Immediate and continuous feedback
    • Support browsing
    • Details on demand
Based on the related work below, we suspect that the two best options for displaying time frames are drop-down boxes or sliding scales or a combination of the two. We will explore the different features offered by each of these methods. The following project describes the use of timeboxes, which are like drag-and-drop boxes, to enable selection of a time frame.
 
 
Timesearcher
Timesearcher: Visual Exploration of Time-Series Data [xiv]
Timesearcher is prototype environment for interactive querying and exploration of time-series data. Queries are built using timeboxes, a graphical, direct-manipulation metaphor for the specification of queries over time-series datasets. These timeboxes support interactive formulation and modification of queries. The prototype includes windows for timebox queries, individual time-series, and details-on-demand. Other features include drag-and-drop support for query-by-example and graphical envelopes for displaying the extent of the entire data set and result set from a given query. Query manipulation tools including pattern inversion and 'leaders & laggards' graphical bookmarks provide additional support for interactive exploration of data sets.

The properties of the timebox are further described in Dynamic query tools for time series data sets: timebox widgets for interactive exploration [xvii]. They are rectangular widgets that can be used in direct-manipulation graphical user interfaces (GUIs) to specify query constraints on time series data sets. Timeboxes are used to specify simultaneously two sets of constraints: given a set of N time series profiles, a timebox covering time periods x1...x2 (x1<x2) and values y1...y2(y1≤y2) will retrieve only those n ∈N that have values y1≤y≤y2 during all times x1≤x≤x2.
 
Figure 5. The screenshot of Timesearcher below shows a visualization of students in a classroom. We created this visualization with a text file formatted for use in TimeSearcher that documented student names and number of entries. The top left window shows student participation, over a single class lecture, with an orange timebox drawn to select a specific time frame. The window on the top right displays time periods during the lecture with lecture topics during a specific time period. The bottom right window shows student names. Clicking on these names highlights their participation on the graph.


 
 
See Appendix A for more TimeSearcher screenshots.
 
A Temporal Communication Flow Visualizer for Social Network Analysis [vii]
This project describes a sliding time frame algorithm to visually analyze the evolution of communication patterns over time. The layout of the graph is automatically recalculated every day, resulting in an interactive movie.

The essential concept of the sliding time frame algorithm is to display active ties between actors in a sliding time frame covering a flexibly selected interval of n days starting from the specific day the visualization is showing. The window frame moves forward day by day, and new ties are subsequently added to the graph each day until the desired width n of the sliding time frame is reached. This time frame window allows users to foresee the activities happening inside the time frame after the current day. By default, all the old communication activities before the current time frame window are included in the layout of the graph.

The sliding time frame concept would be a useful way of allowing a professor to select a particular period of time. It would not need to be limited to day-long periods, but could also be adjusted according to individual lectures, weeks, or semesters.

Figure 6. The time frame moves to day d as the animation progresses. Day d is the current day that the visualization is showing and the current time frame is [d, d+n]. All communications through day (d+n) are calculated and displayed, and if a communication takes place before or on day d, it is active.
Figure 7. In the “No history” mode, only the edges in the current window are included. The time frame moves to day d as the animation goes. Thus, day d is the current day that the visualization is showing and the current time frame is [d, d+n]. Only communications inside the current time frame are calculated and displayed, and only communications on day d are considered active.
 
See Appendix B for more related visualization examples.

Design Process

 

Tools

We used existing visualization tools such as Spotfire and Tableau to perform our data explorations. For the prototype design of our visualization, we used Photoshop combined with HTML and Javascript. For next semester, we are investigating other tools such as Java Applets, Flash, or AJAX, but do not feel we are at a point to commit to any particular tool or level of interactivity.

 

Dataset

The data we will use is made up of chat logs for the IRC channel from October 2004 to the present. Because some of the discussions that take place on the channel are private or sensitive, the privacy of all participants has been protected by changing their usernames. The chat logs contain a date and time stamp, user names, and log entries. There are also robot and channel operator entries.
 
Nov 21 10:51:32 <tamara_> "What is the matrix?"
Nov 21 10:51:52 <benji>this is pretty cool
Nov 21 10:52:35 <jen>I want to know if they will display rich media types
Nov 21 10:52:35 < jen >ie. pictures and such
Nov 21 10:52:42 < benji >the xml and such
Nov 21 10:52:43 <whitney>good question jen
Nov 21 10:55:19 <gopher>benji jen: are we supposed by buy Johnny's book for the reading?
We have used this data to extract information about times (which can be overlaid with class times, important dates, etc), users, and lines of contribution within a discussion.
 

Visualizations of SIMS Chat Logs

Figure 8. Total Chat Entries By User Between Oct 2004 and Oct 2005

Any member of the SIMS community has access to the backchannel. Most students have entered the backchannel at least once, although not all of them have and some only enter it sporadically. A visualization of users indicates that usage follows a Power Law curve. Usage follows an exponential drop off with a gradual decline at the tail end of the curve.
 
Figure 9. Trends in Chat Log Usage over a 24 Hour Time Frame

Participants in the SIMS chatroom are driven by a desire for a sense of community. People are "searching for a feeling of community that's been lost as many "third places" (not work, not home, but a third place where people congregate and interact) have closed down." There are many indicators of the SIMS backchannel as a third place. Participant usage increased during class time but also in the evenings, as this graph shows. This suggests that an in-class chat tool could be enhanced by out of class uses, such as study sessions.
 
Figure 10. Peaks in Usage During Particular Class Hours in the Fall of 2004

Chat use peaks during class hours, indicating that students voluntarily choose to participate in the chatroom while in class. Student motivations will have to be further analyzed to determine how to facilitate similar motivations when the backchannel is an academically drive environment, rather than a combination of academic and social.
 
Figure 11. Number of Chat Entries Over First Six Weeks of Spring 2005 Academic Semester

User count is plotted versus the first six weeks of the Spring 2005 academic semester. Visualizations of user entries versus time periods highlights adoption curves over time. The visualization suggests that community participation increases as the academic semester progresses.
 

User Testing

First Round Interviews
Needs Assessment
 
We conducted three informal interviews of SIMS professors to determine their perspectives on a backchannel discussion. These were not formal interviews, nor did we ask about visualizations in particular. Given the novelty, but relevance, of this topic we wanted to acquire a general idea of professor's view of the backchannel before begining our design process. The professors we interviewed were Bob Glushko, Larry Downes, and Ray Larson. The key points from our discussions are highlighted here. Because the nature of the backchannel could potentially cause concerns about privacy and personal involvement, we chose to compile the salient points from our interviews in an anonymous format.

    • Disconcerting sometimes because we don't know what's happening in that backchannel.
    • When a whole bunch of people start smiling broadly or snickering, you sometimes wonder if you said something weird or what.
    • "You're speaking Dutch today, we [students] don't understand you."
    • Depends on style of course - 200 people, lecture-style versus small discussion seminar.
    • Elicit certain kinds of problem solving skills that might be valuable.
    • Should it be anonymous?
    • Don't want to stifle legitimate discourse, but want to stifle illegitimate discourse. What's the right metrix?
    • How can it encourage more class discussion?
    • Students could double-check references on google.
    • Measure of coherence based on density and bandwidth of class. "Would you explain that in English?"
    • Might be useful, interesting possibility that people can actually combine lecture and debate at the same time.
    • Why would you need a backchannel? Is there a communication void?
    • Disconnect of not knowing what's going on.
    • What's missing from main conversation? Main conversation is limited by size, distance, features.
 
 
Second Round Interviews
Prototype Testing
 
We conducted three interviews of SIMS professors and TAs using our visualization prototype. Again, to retain the privacy of the individuals, we compiled their feedback into a set of key points in an anonymous format.

    • In a small class, could have names overlayed directly on the lines or mapped to a list of names below instead of having to hover over each line to see who the user is.
    • Like seeing total participation in black
    • Hard to distinguish between overlapping pastel lines.
    • Useful if hovering over a line would make it brighter and larger, or more easy to visualize that individual line.
    • Don't like drop-downs!
    • Drop-downs would take too many clicks
    • Could have clickable calendar with time and duration selection options.
    • Could have sliding scale that adjusted real-time, ie between month/day/hour, etc.
    • Sliding scale could have beginning time on left end of scale and ending time on right end of scale.
    • Would be useful to have average participation rates to provide some context for this lecture or time frame as compared to average usage.
    • Use NLP to visualize patterns, such as when a students posts a question and others post links to URLs as answers.
    • Need to better indicate what high and low participation rates actually mean.
    • Will the lines always be as smooth as they are here? What if a student only contributes one comment? Perhaps they can be compiled over a particular scale, such as 8 15-minute sample points in a two hour period or 4 week-long sample periods over a month.
    • How to visualize discourse?
    • Difficult to track or make a judgment about what's going on with a particular user.
    • Drill-down through visualization to see logs - drill down into time period to get to actual log entries
    • Zoom in on context, slice by time, such as a two minute period with a lot of activity and remember "oh, that was that joke I did!"
    • How could it be used to run real-time in the classroom and displaying what's happening?
    • Need more context to know what students are talking about.
    • If it's more like an official IRC then people will stay more on topic.
    • Helpful to indicate if people understand the material.
    • Teachers could use to help determine grades based on class participation.
 

Visualization

The current prototype can be found here: http://www.sims.berkeley.edu/academics/courses/is247/f05/projects/ircchat/prototype/chatviz.html

Design Goals

Our main goal was to design a visualization that would allow instructors to explore data related to in-class IRC discussions. Past experience in designing software for professors has shown that there is a wide range in terms of attitudes and experience with technology. It has also shown that professors consistently desire tools that are easy to use and efficient. Though the purpose of visualization is often exploratory rather than task-driven, we nevertheless recognized the need to create a tool that would be intuitive enough to use at a glance.

Aside from the usability of the tool, it was also imperative that we examine what views of the data would be most interesting to an instructor. We determined that the following aspects would be relevant for our purposes:

  • Discussion during class. Instructors may wish to visualize discussion over the course of a particular class or lecture.
  • Discussion over the semester. Instructors may also wish to view trends in discussion over an entire semester.
  • User distribution. This would be especially beneficial to instructors wishing to view discussion on an individual basis, e.g. to determine participation rates of students.
  • Relation of chat to course material. Instructors may want to draw links between material and chat participation.

From this analysis, we realized that the most important area of focus for our visualization would be viewing trends over time. This would include viewing discussion over short periods (a single class) as well as long term trends (a semester or year view). We chose to use trends over time as the major focus of our tool, coupled with the ability for the user to zoom in order to adjust the time period. Because we aimed to keep the visualization simple and clean, we kept the design spare, with additional details available on demand, when the user mouses over or clicks a section of the visualization.

In the design of our visualization, we encountered several interesting design challenges. First, choosing a method for zooming that was simple, apparent, and efficient was difficult. We decided to begin with drop down menus, as we felt these would be simple for users to understand and use, though perhaps not the best use of visualization techniques. We hoped to refine the zooming technique with user feedback, and plan to create a more visually-based zoom feature as part of our future work.

We also thought that text analysis might be an interesting feature to incorporate, possibly supplying users with a list of frequent words, or using it to draw correlations between discussion content and course topics. After a brief analysis of common words in our data set, we realized that this would be a tremendous challenge, but one we are certainly still interested in experimenting with.

The idea of overlaying class times and important events (such as exams and paper due dates) with log data also seemed promising. We examined the possibilities of collecting such data, including user tagging or manual entry from another source. This is another feature we would like to explore further in our future work.

Lastly, we found the idea of users tagging their own content to be interesting. For example, users entering a relevant question in the channel during lecture could tag the line with a [question] or similar tag, which the system could use to parse the content for instructor analysis. This is an idea that would certainly need to be tested thoroughly with users.

Prototype

The first iteration of our prototype was a simple mockup, created with Photoshop. It's intent was to elicit initial feedback, and convey the idea of interaction techniques. In Figure 12, the user is mousing over one of the graph lines, which displays a tooltip with the name of the individual user (in this case, Sarita Yardi).


Figure 12. First mockup, created with photoshop.

Next, we moved to creating a more interactive prototype. This prototype used simple HTML and Javascript, coupled with wizard of oz techniques to give the appearance of interaction. The user could mouse over the endpoints on each line to get information about the user. During testing, the participants were asked to zoom to a specific date, between 9:00 am and 1:00 pm, at which point they were taken to a zoomed in visualization.



Figure 13. Interactive prototype screen.
 

Figure 14. Zoomed in view of interactive prototype, after the user selects the more narrow date and time range.

Visual Properties

Our primary question in designing the visual data presentation was: Which visual components make it easiest for a professor or teacher to visualize the data in the most appropriate ways? We hoped to create a tool that was simple enough in appearance not to overwhelm the average user, while still providing the necessary features for full exploration.

We selected a simple line graph visualization because we thought it to be both intuitive and familiar to professors and teachers. We were looking to balance between novelty and visual appeal with functionality and efficiency. We would lean towards more emphasis on the latter constraints in order to increase the likelihood that professors would feel comfortable using the tool. We liked Martin Wattenberg’s BabyNames visualization as a model because it is easy, simple, and intuitive. Minimal instructions are needed and the learning curve is quick. Furthermore, the colors are visually pleasing and easy on the eye for continuous interaction.

We felt that zooming would be an important feature of our tool, and hope to expand on this component in the future. Our prototype used a simple drop down menu for zooming in or out, though our research on existing tools has given us alternate ways methods of zooming through time visually.

We also implemented brushing so that the user could quickly and intuitively scan the graph for salient information. For example, he can search by specific student, by time scale, or by discussion. All of these can be done by simply brushing the mouse over the visualization and pausing on the relevant curves. In particular, brushing is useful to display point connections between closely connected threads, to better understand which conversations were relevant and active, based on the professor's lecture. Highlighting provided a very quick, high-level ability to visualize students who participated in a particular chat. We also used a details on demand feature to keep the interface free of extraneous information, and give the interface a simple, uncluttered appearance. By mousing over relevant points on the visualization, the user can obtain specific information that is relevant to him or her, and thus explore the data effectively.

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Conclusions and Future Work

 

Through our design and testing of this visualization, we found that creating a meaningful visualization of discourse is extremely challenging. Not only is the data itself complex, but discovering the needs and goals of users and developing a tool to address those needs also proved difficult. This may be in part due to the exploratory nature of visualizations, as opposed to designing software with more well-defined and specific tasks. Nevertheless, exploring those needs has been highly enlightening and we have made significant progress in our conceptualization of the tool and its design.

With our design, we hoped to create a prototype for a tool that would be simple and efficient. Through user testing, we discovered that our method of zooming was not preferred, which was an expected result. Users did not like the drop downs, and instead suggested sliding scales or calendar-like interfaces. We also found that our colors were not distinguishable enough, possibly due in part to browser displays, and that users would prefer highlighting methods to aid in tracking a single user. Users understood the complexity of correlating discussion content with a visualization, but also felt that it would make the visualization more useful.

We plan on continuing the development of our visualization, incorporating user feedback into the next design phase. Because our design method used simple HTML and JavaScript, it was fast and flexible enough to accommodate significant design revisions. We plan to incorporate features requested most by our participants, such as visually-based zoom, highlighting, and text analysis.

We also hope to develop a method for viewing the data in alternate ways, perhaps by selecting specific students and time periods. Instructors should be able to visualize topics quickly, and associate them with the data set. We would like to enable more complex dynamic querying through visual components, as in Figures 15 and 16. This allows instructors to choose a query through selection, and be presented with a visualization of query results. We will also explore alternate means of zooming, including the sliding time frames and drop boxes discussed previously, as well as the calendar-like interfaces suggested by test participants.

We expect that our design will change significantly as we develop it further and incorporate more features, but our initial visualization design has given us tremendous insight into the possibilities of visualizing chat. We now have a solid conceptual framework for refining a prototype tool, and hope to explore the possibilities of utilizing such a tool in a general classroom setting.



Figure 15. Left: Student names Right: Lecture times, topics, and number of entries for a particular student. While we did not incorporate these tools into our prototype, we feel that there is potential for professors to use similarly structured menus to select student names and visualize their interactions. These menus are simple and easy to use and would work well with the visualization we designed.
 


Figure 16. This shows each student's participation over the course of the lecture. This visualization might be a useful option for professors to select when they wanted to zoom in on a particular user's behavior. The menus in Figure 15 could be use for this purpose.
 
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test Figure 17. This picture shows 2nd grade students using laptops in the classroom to participate in a common chatroom. It was taken in Nancy Durhake's classroom at the Concord Elementary School in Darien, Illinois. [vxiii]

At the top left of the picture there is a television monitor which is displaying the chatroom discussion in real-time. There is clearly an opportunity to expand on the role of a chat visualization tool outside of the SIMS community and into other environments, such as the K-12 classroom. We hope that our visualization has provided solid guidelines for further development of such a tool.
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Appendix

Appendix A

TimeSearcher Screenshots
 
Figure 18.
 
Figure 19.
 
Figure 20.
 
 

Appendix B

Loom
Figure 21. Loom visualization.[ix]
The threading patterns in two groups. Related posts are placed in a circle.
Left: a group with almost no threading—posts are sent but seldom replied to. The single dots scattered across the screen are a sign of a nonsocial group.
Right: a group with dense threads. Numerous and dense circles suggest a vibrant conversational arena. The circular form is suggestive of a conversational gathering and the scattered dots lend themselves to an interpretation of disconnection.
 
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Chat Circes
Figure 22. The original Chat Circles [x] interface. The local user’s circle is bordered in white (in this image, it is user called magenta”, with the blue circle). Everyone is speaking, except for “it” (in green). Only “ann” is inside of magenta’s hearing range.
 
Figure 23. Chat Circles history interface. Each vertical line represents a user. The horizontal bars represent posting, with hollow bars standing for messages posted outside the local user’s hearing range. The text of postings, shown as solid bars, can be retrieved by mouse-over.
 
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Conversation Thumbnails
Figure 24. In this paper we introduce Conversation Thumbnails [xi], a prototype discussion interface that provides skimming friendly navigation, exploits available metadata to help spotlight important sections of the discussion, and uses a special composition-time search mechanism to help maintain conversational coherence. Figure 24 shows a portion of the interface for an illustrative discussion. The interface has three parts: a navigable overview of the entire conversation, a detail window displaying individual messages, and a composition area for new messages.
 
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Query Sketch
Viewing Results of a Query [vx]

Figure 25. After a query: The target is represented by the thick black line; matching companies are shown with thumbnail graphs

Each time the user releases the mouse while drawing on the graph entry panel, the applet performs the query and displays the results as a series of thumbnail graphs in the lower portion of the screen, as seen in Figure 25. Several considerations turned out to be important in designing the result display. First, it is helpful to present miniature thumbnail graphs of the stocks retrieved by the query. These snapshots provide instant, comprehensible feedback on the quality of the results. In addition, moving the mouse over a thumbnail displays the full version of the thumbnail overlaid on the main graph entry panel. This allows the user to compare the result directly with their query. Each thumbnail is also accompanied by a numerical indicator of how well it matches the target pattern.

Second, performing the query on mouse release seems to be the most desirable degree of interactivity. Forcing the user to click a “submit” button adds a gratuitous step to each query. Dynamic updates as the mouse moves cause an uninformative and distracting shuffling of the results. Third, it is important to allow users instant access to “drill down” on the thumbnails for more information. Since the point of the query is to find stocks to invest in, we designed the applet so that clicking on a thumbnail brought the user to SmartMoney.com’s stock research web pages.
 
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Netscan
Figure 26. The Netscan dashboard combines the thread tree, piano roll, reply-based sociogram views, message display, and header information.

(A) The thread tree visualization presents information about the structural and temporal history of the selected thread. Selecting a message displays its contents in the message pane (D) below.

(B) The piano roll component displays a list of all posters who are present in the selected thread ordered by the number of posts they contributed. Columns for each day the thread was active contain bars if the poster posted on that day. When the user mouses over each poster, the related posts are highlighted in the thread tree and the interpersonal connection component.

(C) The interpersonal connection component displays a sociogram that relates users with whose they reply to and who reply to them. Posters are located based on the number of responses they send (the x axis) and the number they receive (the y axis).

(D) The message display pane presents the contents of a selected message and controls for replying via Usenet or email.
 
Figure 27. The Netscan thread tree for the thread with the subject “Visual Basic versus Visual C++” from the microsoft.public.vb.general.discussion newsgroup starting on July 13, 2000. In this view, boxes represent messages. A line between two messages indicates that the more recent message is a reply to the earlier message.
 
Figure 28. The Netscan piano roll display presents a ranked list of authors by their total activity and an indication of how much they posted on each day over the lifetime of a specific thread.
 
Figure 29. The Netscan interpersonal connections pane displays the authors in a thread and an indication of how much they replied to and were replied from all other participants over the lifetime of a specific thread.
 
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Webinar
Figure 30 [xii] illustrates the progress over time of the communication activities around preparing and conducting a Webinar, i.e. a Web based conference. The picture in the top left of figure 30 shows the structure of the team preparing the Webinar. This team has high density and relatively low group betweeness centrality, as shown by the first arrow in the center of the graph. The picture in the top right of figure 30 shows a screen shot of the communication pattern during the first time the Webinar was conducted. The practice leader (blue dot) is sending and receiving information in a star structure, the graph in the center as pointed out by the second arrow displays now relatively high centrality. The third picture at the lower left displays the team preparing a rerun of the webinar, again communicating with relatively low centrality (third arrow). The final screen shot in the lower right of figure 30 displays the practice coordinator (red dot) rerunning the Webinar, communicating in a star structure with relatively high centrality (fourth arrow) with his audience.
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References

[i] McCarthy, Joseph F and d. boyd, 2004. Digital Backchannels in Shared Physical Spaces: Attention, Intention, and Contention. In Proc. Of the 2004 ACM Conf. On Computer Supported Cooperative Work (CSCW 2004), 550-553.
[ii] McCarthy, Joseph F and d. boyd, 2005. Digital Backchannels in Shared Physical Spaces: experiences at an academic conference. In Extended Abstracts of the 2005 Conference of Human Factors in Computing Systems (CHI 2005), 1641-1644.
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