5. 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
6. 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)
7. Search construction
Concept building
Boolean logic
Vocabulary
Techniques
Evaluating searches
8. Search construction: Concept
building
Identify major concepts of topic
PICO helps for clinical questions, but the concept can be
applied in other contexts
Example: Do any olfactory identification tests predict the
development of Alzheimer’s disease? ]
http://www.ncbi.nlm.nih.gov/pubmed/22552846
What are the major concepts?
Alzheimer disease
Olfactory tests
Predict?
People/Humans?
9. Search construction: Concept
building
Alternate words / Synonyms
Alzheimer, Alzheimer’s, dementia, cognition
disorders
Olfactory tests, sniffin’ sticks, b-sit, cc sit, smell
identification test
10. Search construction: Boolean
Logic
AND
Alzheimer’
s Disease
Olfactory
test
Alzheimer’ Dementia
s disease
Humans Animals
OR
NOT
11. Search construction: Boolean
Logic
Concept 2
Concept 1
Alzheimer
disease
OR AND
dementia
Olfactory
Identification test
OR
B-sit
OR
Sniffin’ Sticks
OR
Etc.
(alzheimer disease OR dementia) AND (olfactory identification test OR b-sit OR sniffin’
sticks OR …)
13. Search construction:
Vocabulary
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)
14. Search construction:
Vocabulary
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)
20. Search construction:
Techniques
Floating subheadings
Ovid MEDLINE (extract)
1. exp Arthritis, Rheumatoid/
2. exp Inflammatory Bowel
Diseases/
3. cuc.tw.
4. chronic ulcerative colitis.tw.
5. crohn*.tw.
6. ibd.tw.
7. rheumatoid arthritis.tw.
8. or/1-7
9. exp Postoperative
Complications/
10. exp Perioperative Care/
11. su.fs.
12. or/9-11
13. 8 and 12
PubMed (extract)
("inflammatory bowel diseases"[mh] OR
"chronic ulcerative colitis”[tiab] OR cuc[tiab]
OR crohn[tiab] OR "crohn's” [tiab] OR
crohns[tiab] OR ibd[tiab] OR "rheumatoid
arthritis” [tiab]) AND ("postoperative
complications"[mh] OR "perioperative
care"[mh] OR "surgery”[subheading] OR
"post operative"[tiab] OR
"postoperative"[tiab])
21. Search construction: Filters
A predefined search designed to target specific study
methodologies (RCTs, Cohort, Systematic Reviews)
Use a validated filter (whenever possible)
Example: PubMed Clinical Queries – Systematic
Reviews
(systematic review [ti] OR meta-analysis [pt] OR meta-analysis [ti] OR systematic literature review [ti] OR
(systematic review [tiab] AND review [pt]) OR consensus development conference [pt] OR practice guideline
[pt] OR cochrane database syst rev [ta] OR acp journal club [ta] OR health technol assess [ta] OR evid rep
technol assess summ [ta] OR drug class reviews [ti]) OR (clinical guideline [tw] AND management [tw]) OR
((evidence based[ti] OR evidence-based medicine [mh] OR best practice* [ti] OR evidence synthesis [tiab])
AND (review [pt] OR diseases category[mh] OR behavior and behavior mechanisms [mh] OR therapeutics
[mh] OR evaluation studies[pt] OR validation studies[pt] OR guideline [pt] OR pmcbook)) OR ((systematic
[tw] OR systematically [tw] OR critical [tiab] OR (study selection [tw]) OR (predetermined [tw] OR inclusion
[tw] AND criteri* [tw]) OR exclusion criteri* [tw] OR main outcome measures [tw] OR standard of care [tw] OR
standards of care [tw]) AND (survey [tiab] OR surveys [tiab] OR overview* [tw] OR review [tiab] OR reviews
[tiab] OR search* [tw] OR handsearch [tw] OR analysis [ti] OR critique [tiab] OR appraisal [tw] OR (reduction
[tw]AND (risk [mh] OR risk [tw]) AND (death OR recurrence))) AND (literature [tiab] OR articles [tiab] OR
publications [tiab] OR publication [tiab] OR bibliography [tiab] OR bibliographies [tiab] OR published [tiab] OR
unpublished [tw] OR citation [tw] OR citations [tw] OR database [tiab] OR internet [tiab] OR textbooks [tiab]
OR references [tw] OR scales [tw] OR papers [tw] OR datasets [tw] OR trials [tiab] OR meta-analy* [tw] OR
(clinical [tiab] AND studies [tiab]) OR treatment outcome [mh] OR treatment outcome [tw] OR pmcbook))
NOT (letter [http://pwt] wORw n.newlmsp.anpiehr. agroticvle/ b[pst]d O/pRu cbommmeednt_ [sptu])bsets/sysreviews_strategy.html
30. Sources: EMBASE
Similar to PubMed, Ovid
Indexes man more
international journals
Drug indexing is a plus
Uses EMTREE
Includes MEDLINE,
unless you NOT out
31. Sources: Web of Science
Citation database
Times cited & conference
proceedings
Other ISI databases:
Impact Factors
Biosis Previews
32. Sources: Other options
Examine the references of articles of relevance
Included studies and relevant reviews
Use cited by features
Set up email alerts
Contact authors, companies, organizations,
societies, etc
Search for ongoing studies (prelim data)
Hand search important journals (by Impact Factor,
perhaps)
Citation tracking
34. Reporting
See PRISMA statement
“The aim of the PRISMA Statement is to help authors
report a wide array of systematic reviews to assess the
benefits and harms of a health care intervention. PRISMA
focuses on ways in which authors can ensure the
transparent and complete reporting of systematic reviews
and meta-analyses.”
http://www.prisma-statement.org/statement.htm
35. Reporting
See Cochrane Handbook
http://www.cochrane-handbook.org/
Section 6.6
“It should be borne in mind at the outset that the full
search strategies for each database will need to be
included in an Appendix of the review.”
36. Reporting
See Cochrane Handbook
http://www.cochrane-handbook.org/
Section 6.6
In study flow diagram:
number of unique records identified by the searches;
number of records excluded after preliminary screening (e.g. of titles
and abstracts); and
number of records retrieved in full text
37. Reporting
See Cochrane Handbook
http://www.cochrane-handbook.org/
Section 6.6
In abstract:
List all databases searched.
Note the dates of the last search for each database or the period
searched.
Note any language or publication status restrictions (but refer to Section
6.4.9).
List individuals or organizations contacted.”
38. Reporting
See Cochrane Handbook
http://www.cochrane-handbook.org/
Section 6.6
In methods:
List all databases searched.
Note the dates of the last search for each database AND the period
searched.
Note any language or publication status restrictions
List grey literature sources.
List individuals or organizations contacted.
List any journals and conference proceedings specifically handsearched
for the review.
List any other sources searched (e.g. reference lists, the internet).
40. Recap
Spend time developing your search
Search multiple databases
Take notes during process
Give thought to how you want to report on the data
collection
Consult an expert searcher
