1 CS430: Information Discovery Lecture 18 Usability 3

2 Course Administration

3 Information Visualization Human eye is excellent in identifying patterns in graphical data. Trends in time-dependent data. Broad patterns in complex data. Anomalies in scientific data. Visualizing information spaces for browsing.

4 Example: Tilebars The figure represents a set of hits from a text search. Each large rectangle represents a document or section of text. Each row represents a search term or subquery. The density of each small square indicates the frequency with which a term appears in a section of a document. Hearst 1995

5 Pad++ Concept. A large collection of information viewed at many different scales. Imagine a collection of documents spread out on an enormous wall. Zoom. Zoom out and see the whole collection with little detail. Zoom in part way to see sections of the collection. Zoom in to see every detail. Semantic Zooming. Objects change appearance when they change size, so as to be most meaningful. (Compare maps.) Performance. Rendering operations timed so that the frame refresh rate remains constant during pans and zooms.

6 Pad++ File Browser

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9 Collection Viewer Visualization of NSDL collections using: Inxight's Star Tree Viewer [Connect]

10 D-Lib Working Group on Metrics DARPA-funded attempt to develop a TREC-like approach to digital libraries (1997). "This Working Group is aimed at developing a consensus on an appropriate set of metrics to evaluate and compare the effectiveness of digital libraries and component technologies in a distributed environment. Initial emphasis will be on (a) information discovery with a human in the loop, and (b) retrieval in a heterogeneous world. " Very little progress made. See:

11 MIRA Evaluation Frameworks for Interactive Multimedia Information Retrieval Applications European study Chair Keith Van Rijsbergen, Glasgow University Expertise Multi Media Information Retrieval Information Retrieval Human Computer Interaction Case Based Reasoning Natural Language Processing

12 MIRA Starting Point Information Retrieval techniques are beginning to be used in complex goal and task oriented systems whose main objectives are not just the retrieval of information. New original research in Information Retrieval is being blocked or hampered by the lack of a broader framework for evaluation.

13 MIRA Aims Bring the user back into the evaluation process. Understand the changing nature of Information Retrieval tasks and their evaluation. 'Evaluate' traditional evaluation methodologies. Consider how evaluation can be prescriptive of Information Retrieval design. Move towards balanced approach (system versus user). Understand how interaction affects evaluation. Support the move from static to dynamic evaluation. Understand how new media affects evaluation. Make evaluation methods more practical for smaller groups. Spawn new projects to develop new evaluation frameworks

14 MIRA Approaches Developing methods and tools for evaluating interactive Information Retrieval. Possibly the most important activity of all. User tasks: Studying real users, and their overall goals. Improve user interfaces is to widen the set of users Develop a design for a multimedia test collection. Get together collaborative projects. (TREC was organized as competition.) Pool tools and data.

15 Evaluation of Usability Observing users (user protocols) Focus groups Measurements effectiveness in carrying out tasks speed Expert review Competitive analysis

16 Focus Group A focus group is a group interview Interviewer Potential users Typically 5 to 12 Similar characteristics (e.g., same viewpoint) Structured set of questions May show mock-ups Group discussions Repeated with contrasting user groups

17 Usability Laboratory Concept: Monitor users while they use system Evaluators User one-way mirror

18 Usability Laboratory

19 Usability Laboratory Observing techniques Human observer Video camera Tape recording Study techniques Human protocol (user talks aloud while using system) User carries out specified list of tasks Software designer presents story board (mock-up) to user

20 Eye Tracking

21 Eye Tracking

22 Measurement Basic concept: log events in the users' interactions with a system Examples from a Web system Clicks (when, where on screen, etc.) Navigation (from page to page) Keystrokes (e.g., input typed on keyboard) Use of help system Errors May be used for statistical analysis or for detailed tracking of individual user.

23 The Search Explorer Application: Reconstruct a User Sessions

24 The Importance of Design Good support for users is more than a cosmetic flourish Elegant design, appropriate functionality, & responsive system: => a measurable difference to their effectiveness A system that is hard to use: => users may fail to find important results, or mis-interpret what they do find => user may give up in disgust A computer system is only as good as the interface it provides to its users