GOMS Analysis & Web Site Usability

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SIMS 202
Information Organization
and Retrieval
Prof. Marti Hearst and Prof. Ray Larson
UC Berkeley SIMS
Tues/Thurs 9:30-11:00am
Fall 2000
Today
Review Basic Human-Computer
Interaction Principles
 Starting Points for Search

UI and Viz in IA:
Chapter Contents
Human-Computer Interaction
(HCI)

Human
– the end-user of a program
– the others in the organization

Computer
– the machine the program runs on

Interaction
– the user tells the computer what they
want
– the computer communicates results
Slide by James Landay
What is HCI?
Task
Organizational &
Social Issues
Design
Technology
Humans
Slide by James Landay
Shneiderman on HCI

Well-designed interactive computer
systems promote:
– Positive feelings of success, competence,
and mastery.
– Allow users to concentrate on their
work, rather than on the system.
Usability Design Goals

Ease of learning
– faster the second time and so on...

Recall
– remember how from one session to the next

Productivity
– perform tasks quickly and efficiently

Minimal error rates
– if they occur, good feedback so user can
recover

High user satisfaction
– confident of success
Slide by James Landay
Usability Slogans
(from Nielsen’s Usability Engineering)
 Your best guess is not good enough
 The user is always right
 The user is not always right
 Users are not designers
 Designers are not users
 Less is more
 Details matter
Adapted from slide by James Landay
Design Guidelines
 Set of design rules to follow
 Apply at multiple levels of design
 Are neither complete nor orthogonal
 Have psychological underpinnings (ideally)
Adapted from slide by James Landay
Who builds UIs?

A team of specialists (ideally)
–
–
–
–
–
–
graphic designers
interaction / interface designers
technical writers
marketers
test engineers
software engineers
Slide by James Landay
How to Design and Build UIs
Task analysis
 Rapid prototyping
 Evaluation
 Implementation

Iterate at
every stage!
Design
Evaluate
Prototype
Adapted from slide by James Landay
Task Analysis
Observe existing work practices
 Create examples and scenarios of
actual use
 Try out new ideas before building
software

Slide by James Landay
Rapid Prototyping


Build a mock-up of design
Low fidelity techniques
– paper sketches
– cut, copy, paste
– video segments

Interactive prototyping tools
– Visual Basic, HyperCard, Director, etc.

UI builders
– NeXT, etc.
Slide by James Landay
Evaluation
Test with real users (participants)
 Build models
 Low-cost techniques

– expert evaluation
– walkthroughs
Slide by James Landay
Information Seeking Behavior

Two parts of a process:
» search and retrieval
» analysis and synthesis of search results

This is a fuzzy area; we will look at
several different working theories.
Standard Model

Assumptions:
– Maximizing precision and recall
simultaneously
– The information need remains static
– The value is in the resulting document
set
Problem with Standard Model:

Users learn during the search
process:
– Scanning titles of retrieved documents
– Reading retrieved documents
– Viewing lists of related topics/thesaurus
terms
– Navigating hyperlinks

Some users don’t like long
disorganized lists of documents
“Berry-Picking” as an Information
Seeking Strategy (Bates 90)

Standard IR model
– assumes the information need remains
the same throughout the search process

Berry-picking model
– interesting information is scattered like
berries among bushes
– the query is continually shifting
A sketch of a searcher… “moving through many
actions towards a general goal of satisfactory
completion of research related to an information
need.” (after Bates 89)
Q2
Q4
Q3
Q1
Q0
Q5
Implications
Interfaces should make it easy to
store intermediate results
 Interfaces should make it easy to
follow trails with unanticipated
results
 Makes evaluation more difficult.

Search Tactics and Strategies

Search Tactics
– Bates 79

Search Strategies
– Bates 89
– O’Day and Jeffries 93
Tactics vs. Strategies

Tactic: short term goals and
maneuvers
– operators, actions

Strategy: overall planning
– link a sequence of operators together to
achieve some end
Information Search Tactics
(after Bates 79)

Source-level tactics
– navigate to and within sources

Term and Search Formulation tactics
– designing search formulation
– selection and revision of specific terms within
search formulation

Monitoring tactics
– keep search on track
– (should really be called a strategy)
Term Tactics

Move around a thesaurus
– (more on this in 2nd half of class)
Source-level Tactics

“Bibble”:
– look for a pre-defined result set
– e.g., a good link page on web

Survey:
– look ahead, review available options
– e.g., don’t simply use the first term or first
source that comes to mind

Cut:
– eliminate large proportion of search domain
– e.g., search on rarest term first
Source-level Tactics (cont.)

Stretch
– use source in unintended way
– e.g., use patents to find addresses

Scaffold
– take an indirect route to goal
– e.g., when looking for references to
obscure poet, look up contemporaries
Monitoring Tactics
(strategy-level)

Check
– compare original goal with current state

Weigh
– make a cost/benefit analysis of current or
anticipated actions

Pattern
– recognize common strategies


Correct Errors
Record
– keep track of (incomplete) paths
Additional Considerations
(Bates 79)



Need a Sort tactic
More detail is needed about short-term
cost/benefit decision rule strategies
When to stop?
– How to judge when enough information has been
gathered?
– How to decide when to give up an unsuccesful
search?
– When to stop searching in one source and move
to another?
After the Search
How to synthesize information is part
of the information use process
 One “theory” is called sensemaking

– Russell at al. paper
– Dan Russell is speaking today at 4pm! Room 110. Different topic.
Post-Search Analysis Types
(O’Day & Jeffries 93)







Trends
Comparisons
Aggregation and Scaling
Identifying a Critical Subset
Assessing
Interpreting
The rest:
» cross-reference
» summarize
» find evocative visualizations
» miscellaneous
SenseMaking (Russell et al. 93)


The process of encoding retrieved
information to answer task-specific
questions
Combine
– internal cognitive resources
– external retrieved resources

Create a good representation
– an iterative process
– contend with a cost/benefit tradoff
The SenseMaking Loop,From Russell et al., 93
Observed Activities
of Business
Analysts Working
From Russell et al.,93
The SenseMaking Process,From Russell et al.,InterCHI 93.
Sensemaking (Russell et al. 93)

An anytime activity
– At any point a workable solution is
available
– Usually more time -> better solution
– Usually more properties -> better
solution
Sensemaking (Russell et al. 93)

A good strategy
– Maximizes long term rate of gain
– Example:
» new technology brings more info faster
» this causes a uniform increase in useful and
useless information
» best strategy: throw out bad stuff faster
Sensemaking (Russell et al. 93)

Most of the effort is in the synthesis
of a good representation
– covers the data
– increase usability
– decrease cost-of-use
UI and Viz in IA:
Chapter Contents
Starting Points for Search

Types:
– Lists
– Overviews
» Categories
» Clusters
» Links/Hyperlinks
– Examples, Wizards, Guided Tours
Starting Points for Search

Faced with a prompt or an empty
entry form … how to start?
– Lists of sources
– Overviews
» Clusters
» Category Hierarchies/Subject Codes
» Co-citation links
– Examples, Wizards, and Guided Tours
– Automatic source selection
List of Sources
Have to guess based on the name
 Requires prior exposure/experience

Dialog box for chosing sources in old lexis-nexis inte
Overviews in the User
Interface

Supervised (Manual) Category Overviews
– Yahoo!
– HiBrowse
– MeSHBrowse

Unsupervised (Automated) Groupings
– Clustering
– Kohonen Feature Maps
Incorporating Categories into
the Interface
Yahoo is the standard method
 Problems:

– Hard to search, meant to be navigated.
– Only one category per document (usually)
Evidence

Web search engines are heavily using
– Link analysis
– Page popularity
– Interwoven categories

These all find dominant home pages
More Complex Example:
MeSH and MedLine

MeSH Category Hierarchy
– Medical Subject Headings
–
–
–
–

~18,000 labels
manually assigned
~8 labels/article on average
avg depth: 4.5, max depth 9
Top Level Categories:
anatomy
animals
disease
drugs
diagnosis
psych
biology
physics
related disc
technology
humanities
Category Labels

Advantages:
–
–
–
–

Interpretable
Capture summary information
Describe multiple facets of content
Domain dependent, and so descriptive
Disadvantages
– Do not scale well (for organizing documents)
– Domain dependent, so costly to acquire
– May mis-match users’ interests
MeshBrowse
(Korn & Shneiderman95)
Grow the category structure gradually
and in response to semantic similarity
HiBrowse (Pollitt 97)
Show combinations of categories
given that some categories already
seen
Large Category Sets

Problems for User Interfaces
» Too many categories to browse
» Too many docs per category
» Docs belong to multiple categories
» Need to integrate search
» Need to show the documents
Text Clustering
Finds overall similarities among
groups of documents
 Finds overall similarities among
groups of tokens
 Picks out some themes, ignores
others

Scatter/Gather
Cutting, Pedersen, Tukey & Karger 92, 93, Hearst & Pedersen
95

How it works
– Cluster sets of documents into general “themes”,
like a table of contents
– Display the contents of the clusters by showing
topical terms and typical titles
– User chooses subsets of the clusters and reclusters the documents within
– Resulting new groups have different “themes”


Originally used to give collection overview
Evidence suggests more appropriate for
displaying retrieval results in context
S/G Example: query on “star”
Encyclopedia text
8 symbols
68 film, tv (p)
97 astrophysics
67 astronomy(p)
10 flora/fauna
14 sports
47 film, tv
7 music
12 steller phenomena
49 galaxies, stars
29 constellations
7 miscelleneous
Clustering and re-clustering is entirely automated
Using Clustering in Document
Ranking
Cluster entire collection
 Find cluster centroid that best
matches the query
 This has been explored extensively

– it is expensive
– it doesn’t work well
Two Queries: Two Clusterings
AUTO, CAR, ELECTRIC
8 control drive accident …
AUTO, CAR, SAFETY
6 control inventory integrate …
25 battery california technology … 10 investigation washington …
48 import j. rate honda toyota …
12 study fuel death bag air …
16 export international unit japan
61 sale domestic truck import …
3 service employee automatic …
11 japan export defect unite …
The main differences are the clusters that are central to the query
Another use of clustering
Use clustering to map the entire huge
multidimensional document space into a
huge number of small clusters.
 “Project” these onto a 2D graphical
representation

– Group by doc: SPIRE/Kohonen maps
– Group by words: Galaxy of
News/HotSauce/Semio
Clustering Multi-Dimensional
Document Space
(image from Wise et al 95)
(from Chen et al., JASIS 49(7)
Kohonen Feature Maps on T
Study of Kohonen Feature Maps




H. Chen, A. Houston, R. Sewell, and B.
Schatz, JASIS 49(7)
Comparison: Kohonen Map and Yahoo
Task:
– “Window shop” for interesting home page
– Repeat with other interface
Results:
– Starting with map could repeat in Yahoo (8/11)
– Starting with Yahoo unable to repeat in map
(2/14)
UWMS Data Mining Workshop
Study (cont.)

Participants liked:
– Correspondence of region size to #
documents
– Overview (but also wanted zoom)
– Ease of jumping from one topic to
another
– Multiple routes to topics
– Use of category and subcategory labels
UWMS Data Mining Workshop
Study (cont.)

Participants wanted:
–
–
–
–
–
–
–
–
–
hierarchical organization
other ordering of concepts (alphabetical)
integration of browsing and search
corresponce of color to meaning
more meaningful labels
labels at same level of abstraction
fit more labels in the given space
combined keyword and category search
multiple category assignment (sports+entertain)
UWMS Data Mining Workshop
Visualization of Clusters
– Huge 2D maps may be inappropriate
focus for information retrieval
» Can’t see what documents are about
» Documents forced into one position in
semantic space
» Space is difficult to use for IR purposes
» Hard to view titles
– Perhaps more suited for pattern
discovery
» problem: often only one view on the space
Summary: Clustering

Advantages:
– Get an overview of main themes
– Domain independent

Disadvantages:
– Many of the ways documents could group
together are not shown
– Not always easy to understand what they mean
– Different levels of granularity
Next Time
Interfaces for Query Specification
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