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Question
Protocol
Literature Search
Study Selection
Study Appraisal
Data Extraction & Analysis
Presenting Results
Slide courtesy of Whitney
Townsend
Why search?
A high-quality lit search is essential for a successful meta-analysis
It is from the search results that data is gathered for analysis
Failure to locate important studies can significantly affect results
Remember the goal is to capture every relevant study
Important to report search so your methodology can be reproduced
What to expect?
Expect 1000s of results
Expect to search multiple databases
Ovid, EMBASE, PubMed, Scopus, etc.
Expect the search process to take awhile
Expect to publish search strategy and search
methodology
Expect to consult a professional with search
expertise (health sciences librarian)
Constructing Effective
Searches
Break topic into key components
Do not search in full sentences
Example:
If a patient has caries, do composites (compared to
amalgams) have an increased risk of marginal breakdown?
Constructing Effective
Searches
Break topic into key components
Do not search in full sentences
Example:
If a patient has caries, do composites (compared to
amalgams) have an increased risk of marginal breakdown?
P –
I –
C –
O –
Constructing Effective
Searches
Break topic into key components
Do not search in full sentences
Example:
If a patient has caries, do composites (compared to
amalgams) have an increased risk of marginal breakdown?
P – Caries
I – Composites
C – Amalgam
O – Marginal breakdown
Boolean Logic
ANDComposit
e resins
Dental
amalgam
Dental
amalgam
Composit
e resins
AnimalsHumans
OR
NOT
Concept 2
Boolean Logic
Concept 1
Dental Caries
Cavities
ANDOR
OR
OR
(dental caries OR cavities) AND (amalgam OR dental amalgam)
Amalgam
Dental Amalgam
Etc.
Search Terminology
Keywords
Controlled
vocabularies
What are they?
Literal search
Looks for occurrences of words
When to use?
Current topics
Not easy to describe concepts
No vocabulary exists in database
Examples
Drug names (Lipitor, Prozac)
Slang
Concepts (Swine flu, oil spill)
Search Terminology
Keywords
Controlled
vocabularies
What are they?
Set of words or phrases used to describe
concepts
Dictionary of accepted terms for a database
When to use?
Searching a database that uses one
Examples
MeSH (Medical Subject Headings)
EMTREE (Embase)
Common Techniques
Truncation ----------- composite*, amalgam*, periodont*, dent*
Adjacency ----------- screen* adj5 cancer
Phrases ----------- “dental caries”, “periodontal disease”
Parentheses ----------- (“dental caries” OR caries) AND
“periodontal disease”
Note: Techniques vary from database to database