MODULE THREE

ELECTRONIC INFORMATION SEARCHING TECHNIQUES

Nancy KamauKenya Methodist Univeristy

P.O.Box 267-60200 MERU, KenyaE-mail: nancy.kamau@kemu.ac.ke

Learning ObjectivesThe student will learn :- • Process of search preparation• Various Search techniques • Importance of search techniques in information retrieval

On successful completion of the module, one should be able to:- • Develop search strategies • Understand the role of search techniques•Apply search techniques in searching

Learning Outcomes

Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it."            -Samuel Johnson, 1744

To search is to “try find something by looking carefully and thoroughly”

(Pocket Oxford Dictionary, 2002)

This implies that searching requires thorough preparation

Information Searching

Good searches are planned not accidental

User requirement in searching To get good searches:

Define the topic clearlyChoose appropriate keywordsUse search techniques

Define the topic clearly•Formulate the search statement or search question in full Eg malaria infection in children in Africa•Breakdown the research topic into main components/keywords Concepts/keywords - malaria, infection, children, africa

Use search techniques where appropriate

Choose appropriate keywordsTaking into consideration: •Key concepts of the research question•Related terms or Synonyms – adolescent or teenage•Variations in word spelling – English or American•Variations in word endings- plural or singular•Acronyms – HIV/AIDS or full names

Various approaches to searching

•Simple search •Advanced search•Meta search

Search preparation Starting point

•Develop a search topic •Identify the key concepts/keywords in topic•Decide the focus of the topic- General or specific• Have a time span

Search strategyPlan that help to articulate the information required. Covers areas such as

•Purpose of the information The best sources/tools to choose

fromWhat is the geographical location

•Publication period- currency •Focused or general information

Search strategySearch strategy lays the guidelines for an effective search. It helps to:-

•Think through the search topic•Break the topic into concepts or keywords•Decide on alternative words and acronyms. •Use search techniques to refine the search •Decide on which search tools and search techniques to use•Refine the search to retrieve good references

Use of keywords in searching •Keywords are words and phrases used to

closely describe the topic or subject by the author or indexer•Keywords capture the ideas described in a document•Keywords may have related terms, variations in word spelling such as American and English versions, plural or singular versions and synonyms•Most search tools use keywords for information retrieval

Search techniques-Why Search techniques •Search techniques useful for search precision - too few references retrieved - too many references retrieved - no references at all retrieved•If too few: - truncation can be used to include all possible words variations - Boolean OR or NOT can be used to broaden search •Parenthesis/nesting can be used to combine synonyms eg (Adolescents OR teenagers) AND contraceptives

Why use search techniquesToo many searches•Use the Boolean operator AND to focus the search•Use the field searching to limit search to specific fields such as author, languge or year•Use the controlled vocabulary and limit search to subheadings•Use the exact phrase search•Use of advanced search option

Types of search techniques•Boolean Logic•Phrase searching•Truncation and wildcards•Field searching•Parenthesis•Controlled vocabulary e.g MeSH•Subheadings

Boolean logic•Boolean logic is a logical relationship of search terms•Named after British mathematician George Boole (1815-64)•Boolean logic helps the user to achieve relevancy in the search results •Available in most search tools•Advisable to check with “help pages” of each search tool

Uses the following operators AND, OR, NOT •OR - Broadens the search •AND – Narrows and focuses the search•NOT – excludes unwanted words or concepts to focus the search•Uses venn diagrams to illustrate the logical relationship•Operators presented in upper case

Boolean logic (Cont’d)

Boolean logic availability• Full Boolean logic - use of all logical operators• Implied Boolean logic -some search tools default to a Boolean operator such as AND eg PubMed and Google • Use of symbols- + for AND or - for NOT• Boolean logic with use of template that guides in selecting the relationship of the terms – NOT, OR, AND eg PubMed advanced searches

Documents that discuss either mosquitoes OR malaria

OR is suitable when keyword has a synonym

Total 81,883

Documents that discuss both mosquito AND malaria

Total 8,557

Documents that discuss mosquitoes as parasites but

excludes malaria

Total 24,430

Phrase searching•Keywords in quotes “….” eg “HIV/AIDS and tuberculosis” •Instructs search engine to search words inside the quotation marks•Leads to fewer relevant search results •In PubMed, use of phrase searching may omit some relevant citations. •PubMed performs automatic term matching, but when the search words are under quotation marks, the automatic term matching is not done.

•Use of a symbol at the end of a word to retrieve variants of the word.

Symbols used in truncation include:? – represents one character* or $ - represents multiple

charactersExamples- bacter* retrieves- bacteria, bacterial, bacteriological, bacteraemia; bacteremia; bacterium and bacteriophage•User to be careful not to truncate root word to be too short•Check with search tool for availability

Truncation and Wildcards

Field searching•Electronic record presented as a field

•Data fields for the title, author, affiliation, journal or book title, abstract or language• Any of the fields can retrieve information•Field searching is focused eg author search•Search tools such as PubMed allows user to limit search according to fields such as year, language, author, abstract•PubMed provides a template for the user to use a field search

Parenthesis• Use of multiple Boolean operators• Forces the order of how information is retrieved. For example diabetes prevention and control can be searched–Diabetes AND (Prevention OR control). • Keywords in brackets are searched first then matched with results of keyword outside bracket• In absence of brackets all keywords will be searched at the same time and this may affect search results significantly

Controlled vocabulary •Ensures consistency in presentation of information for related topics. •Standardises language used by authors.•Medical Subject Headings (MESH) most known controlled vocabulary or thesaurus •MESH used in the preparation of Medline database. •MESH used as controlled vocabulary and a search tool for PubMed

Mesh tree structure•Organized in 15 main branches •Each article assigned about 5-15 appropriate Mesh headings•Under each branch are descriptors that could be narrower or broader•eg Eye Eyebrows Eyelids Eyelashes •Tree structure allows searching from general to specific leading to more precision or relevance

Mesh tree structure (Cont’d)•PubMed explodes search terms to include narrower terms. •A search on eye diseases can be exploded to include references on eyebrows, eyelids and eyelashes. •User may be interested in an eyelid disease, instead of eye diseases

Use of subject headings•Subject headings help build the search for relevancy and focus. •Subject headings in Medline are assigned subheadings to help achieve search relevancy.•For example – in ‘management of malaria in pregnancy’ using a subheading can help focus the search to management through - drug therapy; nursing or prevention and control •Subject headings are equated to controlled vocabulary/thesaurus

•Information is well organized •Information is filtered and indexed •Selection criteria applied by experts•Information is from known sources such as peer reviewed journals, books and credible institutions•Allows use of search techniques for more focused search results

Searching bibliographic databases

• MEDLINE, CINAHL• HINARI• Cochrane database of systematic

reviews- Specialised

Examples of databases

Pubmed/Medline

•PubMed is the National Library of Medicine's search service that provides access to over 20 million citations in MEDLINE.

•MEDLINE is the National Library of Medicine's bibliographic database of biomedical information resources, indexes4,000+ international biomedical journals Coverage: 1950s to date

http://www.pubmed.gov

Searching Pubmed/MedlineConnect to PubMed through Hinari or http://www.pubmed.gov

Go to HINARI website at www.healthinternetwork.org Select the HINARI LOG IN hyperlink  Enter the HINARI user ID and password and click the sign on buttonGo to the “find articles” section and select the hyperlink “search for articles through PubMed”

PubMed homepage.

PubMed simple search

A search on malaria in africa produces 12,096 citations. This is a large amount that would require narrowing.

PubMed Search: More than two Keywords

Keywords-malaria, treatment, infants, africa: search result= 2223. search can be narrowed

PubMed: use of field search

Use of field search technique: review, infants upto 23 months, and published in 2 years. Search result= 11 (2223)

PubMed advanced search

Use the template to focus the search with field search and Boolean operators

MeSH homepage

http://www.who.int/hinari•Requires username and passwordUsername and password available through the institutional library

Contains 7,500 full text online journals from leading publishersOver 2000 institutions registered in more than 100 countries

HINARI

Requirements for successful information retrieval •Define the search problem•Develop a search strategy•Use search techniques•Learn how to use search tools e.g. PubMed•Consider other forms of information sources such as print and audio-visual•Evaluate retrieved information