Transcript Advanced searching - School of Communication and Information

Advanced searching
All you wanted to know …
© Tefko Saracevic
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Principles of
Searching
Definitions
Advanced (Encarta)
More highly developed …
at a higher stage of development or
progress than other similar people or
things
Advanced searching
that about sums it up
it is searching at a higher level of
complexity without which search goals
cannot be achieved
© Tefko Saracevic
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Definition
Principles of
Searching
Heuristic (Encarta)
problem solving by trial and error
a method of solving a problem for which no formula exists,
based on informal methods or experience, and employing a
form of trial and error (iteration)
using or arrived at by a process of trial and error rather than set
rules
a rule of thumb
commonsense rules indented to increase the probability of
solving some problem
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Principles of
Searching
Advanced searching is
a HEURISTIC process
• It means that searching is a trial & error process
& an iterative process
• It means that searcher can modify a search in
response to results or user
• It is a base for search progression toward more
effective results
• And it is a behind advanced search strategy and
tactics
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Goals of advanced
searching
Principles of
Searching
– achieve higher levels of effectiveness
• getting more relevant, missing more irrelevant stuff
– and at higher level of efficiency
• saving on overall time, cost, effort
– center search toward answers & resources most likely to
be effective
• also: focus unfocused searches &
• get ideas how to proceed
– use all available system features for goals
– act as an professional (extreme) searcher
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Principles of
Searching
In fact
• Any & all vendors & search engines have
advanced search features
– most studies show that users use them rarely, if at all
• In principle most are the same
• But in application they differ from vendor to
vendor, engine to engine – sometimes greatly
– need to be learned individually. What a bummer!
– cannot be taken that what & how works in one works
elsewhere – even though similarities are there
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Levels of advanced
searching
Principles of
Searching
• Advanced searching possible at several levels
– strategic
• using different approaches to fit circumstances or context
independent of but adapted to a system used
– tactical
• using system features to the hilt to achieve given objectives
• but as said, features may & do differ from system to system
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Principles of
Searching
Reminder
• Search strategy (big picture):
– overall approach to searching of a question
• decisions on search resource(s), content & format
• variations in these as a search progresses
• Search tactics (action choices) (small picture):
– choices & variations in search statements, query
• terms, connectors, attributes …
• using capabilities of a system to the hilt to achieve
desired results
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Principles of
Searching
A search strategy is
• The entire approach to a search – selection of
– files and sources to use
– approaches in proceeding to search & combining
• search terms
• operators to use
• fields to search
– formats for viewing results
– alternative actions if search yields
• too much
• too little
– problem-solving heuristics
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Principles of
Searching
Search tactics is
• A query - command line entered into a system
in order to retrieve relevant information
– terms, operators & attributes as allowed by a given
system
– vocabulary & syntax used in conjunction with
connectors &/or limiters to search a system
• Again: depends on a system how it is done
– for example, a search statement in DIALOG might
be: b 47; ss (garbanzo? or chickpeas) and (hum?us
or humus)
– how would you do that in
?
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Principles of
Searching
Some major strategies
• Briefsearch
– also sometimes called
meatball search or quick &
dirty search
• Building block search
• Citation pearl growing
search
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Principles of
Searching
Briefsearch
• Takes little planning & is fast
– searcher gets on to the system quickly, & enters terms
using default (or simple Boolean) operators
– only a few terms are used
– there is no or little reiteration & limited interaction
between searcher & system
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Can also be used for verification purposes
Results can be examined for relevance feedback
Not recommended for comprehensive searches
Widely used by users generally
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Building block strategy
Principles of
Searching
• Commonly used search strategy
– start small & then build upon results
• identification: each important concept or facet of a
search is identified
• elaboration: for each facet terms are identified
• combination: search starts with one or just a few facets;
as it progresses additional facets are connected using
appropriate Boolean operators &/or attributes
• iteration: as a search proceeds terms to facets may be
added, new facets, even subfacets, created & combined
• You build heuristically & modify the query as
you go long adding, changing facets
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Principles of
Searching
Going about building
blocks
Facet 1
REGULATION
OR
FCC
regulation
market structures
regulated industries
© Tefko Saracevic
Facet 2
TECHNOLOGY
technology
technical impact
innovation
technological change
Facet 3
TELECOMMUNICATION
communication
satellite
microwave
telephone
cellular phone
mobile radio
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Principles of
Searching
Getting higher recall
Building block (or
multiple facet)
searching assume
movement from
lower to higher
recall – getting
more stuff that is
relevant, but
precision may be
lowered
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Principles of
Searching
Citation pearl growing
• Another common strategy
• It means what the name
implies: you start with a
nugget & grow upon it
• Starts with a few records of
high relevance
• Aims for more recall
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Principles of
Searching
How to…
citation pearl growing
• Bibliographic & other information is obtained for a relevant
(model) document(s) after a Briefsearch
– user is often the source of the model document(s)
• Terms (pearls) are selected from the documents to build
facets
• Search proceeds iteratively with examination of new
relevant documents to enlarge or modify facets
– use synonyms and Boolean ‘or’ to create more facets
– preserve sets for additional interaction
• This strategy works best if user is present or frequently
consulted about results
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Principles of
Searching
When is citation pearl
growing good to use?
• When word lists or thesauri are not available
• When there isn’t a large recall after doing a briefsearch
• When a client has one or two good articles and wants to
find more like them
• When a topic is new and no descriptors are established
to represent the concept
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Principles of
Searching
Advanced searching on
the web
• Needs to be adapted to differences
– coverage not specified; vastly different from one
source, engine to another
– no controlled vocabulary
– output ranked by unknown methods & criteria for
“relevance”
– building blocks may be indicated by “similar pages” or
“more from this site” or some such
– some provide clusters to narrow searches
– features, capabilities, specifics differ
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Principles of
Searching
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A few web search guides
of many
Advanced web searching Greg Notes
Finding information on the web U of California, Berkeley
Googleguide advanced operators Nancy Blachman
Four NETS for better searching Bernie Dodge
Web search tutorial Searchenginez
• How to choose a search engine or directory SUNY at Albany
• Search the web more efficiently Web Design in New York
• Finding information: search engines Phil Bradley
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Beware: search engines are not
only about search
Principles of
Searching
• Yes, search is (still) their core, but they are in
many other businesses built upon search &
these affect what & how of searching for us
– they are corporations, commercial entities
• have to make money, mostly by ads & placements
– but provide many other services
• selling, licensing software
• email, messenger
• add-on utilities – like your desktop search functions, toolbars
– many of the additional stuff is provided free, but there
is no such thing as free lunch
• basically they are about how search engines can get us to
continue to use their product
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Principles of
Searching
In other words
• Buyers beware!
• Searchers be
aware!
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A few search sources for the
fun of it
Principles of
Searching
• Shakespeare & Internet Search Tools &
Resources
• Picsearch picture searching
• US government official web portal “Whatever you want
or need from the U.S. government”
• Special Search Engines Leiden U, Netherlands, probably
the longest page on the web – a bit out of date
• Yahooligans! the web guide for kids
and a study: Bilal, D. (2000). Children's use of the Yahooligans!
Web search engine. Journal of the American Society for
Information Science, 51 (7), 646-665 [available at RUL]
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Principles of
Searching
Role & importance of
interaction in searching
“At a fundamental level,
information retrieval is
inherently interactive.”
“This becomes apparent as one
considers that the process
revolves around a series of
activities that an information
searcher engages in with an
information environment.”
Savage-Knepshield, P. A. & Belkin, N. J.
(1999).
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Principles of
Searching
Interaction:
key to effective searching
• Interaction between
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user and searcher
searcher & information system
user & searcher with information objects
searcher with support materials (thesauri, codes, etc.)
user & searcher with environment
user & searcher with valuation of results
• All play a part in retrieving satisfying results
• Iteration is a result of interaction
© Tefko Saracevic
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Principles of
Searching
Interactive process
Query
Sources
Search
User
task
question
use
Context
© Tefko Saracevic
Searcher
Iteration
Evaluatio
n
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Principles of
Searching
Ask yourself some
questions
• What strategies & tactics have I developed
for effective searching?
• What heuristics?
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Principles of
Searching
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For a question
ask yourself more questions
What do I do first?
What files/systems should I use?
Should I start broad or narrow?
What will my search statement be?
How much material do I or user need?
What format do I or user want for results?
How will I modify & adjust results?
© Tefko Saracevic
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Principles of
Searching
© Tefko Saracevic
Happy advanced
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