 What to “know”? ◦ Goals of information visualization. ◦ About human perceptual capabilities. ◦ About the issues involved in designing visualization for multiple dimensions and the heuristics for best practices in visualization design.  What to be able to “do”? ◦ Choose and design an effective information visualization for a small data set. ◦ Design a dashboard for a small data set. ◦ Evaluate whether a design is effective or not. 1

 In “business intelligence,” what do we mean by “intelligence”?  Where does “intelligence” come from?  How is “intelligence” produced? 2

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4 Enhanced understanding Improved decision making Clean data Complete data Longitudinal data Consistent data More data Accurate calculations Flexible design Properties Patterns Relationships Comparisons Anomalies Trends Amplify cognition

 Increase available brain resources ◦ Enhance parallel perceptual processing ◦ Offload work from cognitive to perceptual system  Reduce search time  Enhance recognition of patterns ◦ Encourage recognition instead of recall ◦ Enhance “chunking” into appropriate memory sizes for both processing and recall  Provide focus/emphasis ◦ Highlight images with “pop-out” effect 5

 Rapid parallel processing ◦ Feature Extraction: edges, orientation, color, texture, motion ◦ Relies on commonly accepted images (cultural, personal) ◦ Transitory: Uses primarily short-term memory, but can leave impact  Serial goal-directed processing ◦ Object Recognition: visual attention & memory important. ◦ Uses both short-term memory and long-term memory ◦ More emphasis on arbitrary aspects of symbols ◦ Different pathways for object recognition & visually guided motion 6

 Visual properties processed without significant cognition. ◦ No need to focus attention; must stand out ◦ Can be perceived immediately; less than 250 ms ◦ May mislead viewer; may create inappropriate and lasting significant emphasis  The visual properties are: ◦ Color ◦ Motion ◦ Edge segmentation; primitive features ◦ Orientation ◦ Size 7

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9 Parallel Processing Orientation Texture Color Motion Size Detection Edges Regions Light 2D Patterns Serial Processing Object Identification Collation Short Term Memory 5 ± 2 = 3 to 7 Objects

 The goal of information visualization is to enhance understanding and amplify cognition. ◦ Increase available brain resources ◦ Reduce search time ◦ Enhance recognition of patterns ◦ Provide focus/emphasis  Make best use of parallel and serial processing. ◦ Understand how people process images. ◦ Understand the speed with which people process images without conscious thought. 10

 Art is valued for its originality and expressiveness.  Art is valued for pushing the bounds of accepted norms and potentially expanding the definition of those norms.  Design is valued for its fitness to a particular user or task.  Design is valued for its effectiveness and use. 11

 “An affordance is a quality of an object which allows an individual to perform an action.” (Wikipedia) ◦ A knob implies twisting, a string means pulling.  In design, we look at how the affordances of an object reveal how it will be used. ◦ A push plate on a door means that it should be pushed, rather than pulled, open. ◦ A line showing where the average is on a graph means that the viewer should compare the data to the average. ◦ A vertical line means someone should read a table or graph vertically.  Design is “good” when the perceived affordance (“is for”) is equivalent to the actual affordance. 12

 Task rather than the visualization  User rather than the technology  Information content rather than the data  Message rather than the medium  Accuracy rather than beauty 13

 Analyzing ◦ Discover the message in the data.  Monitoring ◦ Track information and look for anomalies.  Planning ◦ Prepare for the future.  Communicating ◦ Send a message to another person. 14

 The differences. Like: ◦ The difference between analyzing and communicating. ◦ The difference between monitoring and analyzing. ◦ The difference between planning and monitoring.  Think what about the differences? ◦ Who does it? ◦ Why is the person doing it? ◦ How does it happen? ◦ What are the results? 15

 Show the data  Induce to viewer to think about the data  Avoid distorting what the data have to say (next 3 slides)  Present many numbers in a small space  Encourage the eye to compare different pieces of data  Reveal the data at several levels of detail, from overview to fine structure  Make large data sets coherent  Serve a clear purpose  Be closely integrated with the statistical and verbal descriptions of a data set. 16

     ibm.com/software/data/cognos/manyeyes/ ibm.com/software/data/cognos/manyeyes/ 17

 Tufte’s principles (short and sweet)  Nielsen’s ten usability heuristics (long and detailed) 18

 Provide the greatest number of ideas in the shortest time with the least ink in the smallest space  Enforce visual comparisons ◦ Show comparisons adjacent in space ◦ Show causality ◦ Show multivariate data ◦ Use direct labeling: Avoid separate legends and keys ◦ Use small multiples (called trellis chart): a number of small, simple adjacent charts to encourage comparison  Avoid “chart junk” 19

1. Visibility of System Status ◦ Always keep users informed about what is going on. ◦ Provide appropriate feedback within reasonable time. 2. System Matches Real World ◦ Speak the users' language, with words, phrases and concepts familiar to the user, rather than system-oriented terms. ◦ Follow real-world conventions, making information appear in a natural and logical order. 3. User Control and Freedom ◦ Users often choose system functions by mistake. ◦ Provide a clearly marked "out" to leave an unwanted state without having to go through an extended dialogue. ◦ Support undo and redo. 20

4. Consistency and Standards ◦ Users should not have to wonder whether different words, situations, or actions mean the same thing. ◦ Follow platform conventions. 5. Error Prevention ◦ Even better than good error messages is a careful design which prevents a problem from occurring in the first place. 6. Recognition rather than Recall ◦ Make objects, actions, and options visible. ◦ User should not have to remember information from one part of the dialogue to another. ◦ Instructions for use of the system should be visible or easily retrievable whenever appropriate. 21

7. Flexibility and Efficiency of Use ◦ Accelerators -- unseen by the novice user -- may often speed up the interaction for the expert user so that the system can cater to both inexperienced and experienced users. ◦ Allow users to tailor frequent actions. 8. Aesthetic and Minimalist Design ◦ Dialogues should not contain information which is irrelevant or rarely needed. ◦ Every extra unit of information in a dialogue competes with the relevant units of information and diminishes their relative visibility. 9. Help users Recognize, Diagnose, and Recover from Errors ◦ Expressed in plain language (no codes) ◦ Precisely indicate the problem ◦ Constructively suggest a solution. 22

10. Help and Documentation ◦ Even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. ◦ Help information should be easy to search, focused on user's task, list concrete steps to be carried out, and not be too large. 23

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