Search and Navigation
Based on the paper,
“Improved Search Engines and Navigation Preference in Personal
Information Management”
Ofer Bergman, Ruth Beyth-Marom, Rafi Nachmias, Noa
Gradovitch, Steve Whittaker
ACM Transactions on Information Systems Vol 26, No 4 Article 20, September 2008
Locating files
 How do you find a file on your computer
 Navigation through the hierarchical directory
system?
 Search?
 Some combination?
 What do you do?
 If more than one, when do you do each kind
of finding?
Personal Information Management
 “An activity in which an individual stores
his/her personal information items in order to
retrieve and use them later.”
 “Such information items include files, emails,
Web favorites, contacts, and notes.”
 What else might we include in that list?
Basic file structures
 We see our file storage structure through a virtual
organization presented by the OS interface.
 The hierarchical structure of items in folders and
folders in directories
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First introduced in the Multics system in the 1960s
Applied to unix and linux
Then Xerox Star
Apple Mac
Microsoft Windows
 Based on the familiar office metaphor of a file cabinet.
Search and Navigation
 Navigation requires a predictable structure.
 You take clues from what you see and follow paths that
appear to take you closer to your goal.
 Two phase, according to the paper:
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Manually traverse their organizational hierarchy to reach
the directory or folder where the item is stored
Locate the desired item within the directory or folder,
possibly using a sorting tool to order things for easier
review.
 Search is independent of real or virtual organization.
 Search term is matched to a goal, which is located by a
pointer.
Navigation
 Classification of information can hide it from the user
 What does this mean to you?
 How does it “reduce the chances of quick retrieval or
reminding”?
 Categorization is cognitively challenging
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What do you do with something that logically belongs in
two or more different places?
Retrieval requires recall of how the information was
classified.
 Note the email study -- “users with many categories
found it harder to file and were more likely to create
spurious unused folders.”
Search
 Given the difficulties associated with categorization
and navigation,
 Assumption made that search would be preferred
 Search
 is more flexible and efficient at retrieval
 does not require remembering storage locations or
classification decisions.
 Bypasses the organizational problem

You don’t have to decide on a way to organize things.
You just specify enough information to identify what you
are looking for and the search tool finds it for you.
Another consideration
 Is there something missing from the
discussion so far?
 Navigation requires categorization on storing
and recalling categories when retrieving
 Search does not require any type of
organization when storing and allows retrieval
if you can specify appropriate characteristics
of what you are looking for.
 ….. ????
Another consideration
 Is there something missing from the
discussion so far?
 Navigation requires categorization on storing
and recalling categories when retrieving
 Search does not require any type of
organization when storing and allows retrieval
if you can specify appropriate characteristics
of what you are looking for.
 What about the view of “neighbors” to the item
you are looking for?
The research
 Two research questions:
 Retrieval: “Search is more efficient and flexible for
retrieval, thus improved quality of search iegines
should lead to a substantial increase in file search and
eventually a preference for search over navigation.”
 File Organization: “Users are known to have problems
organizing files effectively for retrieval. Search allows
retrieval without such manual organization and
improved search should lead to a reduced use of filing
strategies in preparation for later retrieval.
 What do you think about these questions? What
results would you expect, if you explored these
questions among your friends and colleagues?
See paper for citations of relevant sources for these expectations.
Desktop search improvements
 Desktop search tools have improved.
 Cross-format search. You can now find materials from
files and e-mail messages and instant messages and
web history all from one search tool
 Faster retrieval. Some cases of 1000 times faster than
older versions.
 User-centered design. Change of emphasis from an
interface that made things easier (and faster) for the
system to features that are easier for the user (though
more difficult for the system.
 Incremental search. The search begins as soon as you
type the first character. That means you can stop
typing as soon as you see what you are looking for.
Demonstration and discussion
 My directory system and my options with
navigation and search on this Mac (OS X 10.5.5)
 Someone have a PC we can look at?
 Experiences with Google mail -- hierarchical
folders vs. search
The study
QuickTime™ and a
decompressor
are needed to see this picture.
Search engine features
 Interestig side note: range of age of the Mac
users: 15 to 87 for Spotlight, 15 to 93 for
Sherlock! (Windows range from 15 to 55)
QuickTime™ and a
decompressor
are needed to see this picture.
 Note that 37% of Windows users had
removed Google Desktop from their systems
by the time of the followup - 7 months later.
QuickTime™ and a
decompressor
are needed to see this picture.
Remembering location
QuickTime™ and a
decompressor
are needed to see this picture.
When we use search
 When we cannot remember where the file is.
 The experiment resulted in the conclusion
that improved search engines have had very
little affect on the way people locate files on
their computers.
Some conclusions, questions
from the authors
 Possible explanations of preference for navigation
over search
 Consistency: Hierarchical organization always looks
the same. Navigation always proceeds the same way.
Search results may appear in different order or with
different items in the list.
 Recognition vs. Recall: Recognition tasks are easier.
Navigation tasks are based on recognition. Information
addressability -- partial information about the desired
result is required by both navigation and search. Is
there a preference for the type of information
addressability required for navigation over that required
for search?
Conclusions and questions - 2
 Procedural vs. Declarative memory. Search requires
declarative memory -- you must know a characteristic
of the search goal. Navigation depends more on
procedural memory -- we know how to get to what we
want, even if we don’t know exactly where it is.
 Cognitive Automation: Since the user created the
hierarchical arrangement of the materials, less
cognitive attention is required to navigate it. Some of
this becomes automatic, requiring very little user
attention.
 Strength of the location metaphor: We are used to
puttig things in their place and finding them there
when we need them again. In PIM, “the same user
both organizes and retrieves the information.”
Some thoughts, questions
 Saving a file requires specifying a location.
 We could just dump everything into one folder
or the desktop, but are we conditioned to be
more organized than that?
 Having done some sort of organization to store
a file, are we likely to think about that
organization when retrieving it?