1. PICO search strategies
Techniques and tips to answer well-developed clinical
questions using Embase
Wednesday, 22 April 2015
Maura Sostack, MLS, AHIP
EBM Librarian
Evidence-Based Medicine Center
Clinical Solutions
Elsevier Health Sciences

2. Learning Objectives
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 Describe the three concepts that form the basis of a PICO
search strategy.
 Create search filters using natural language words and
phrases and controlled vocabulary terms.
 Identify study type with its corresponding PICO question.

3. Table of Contents
 Deconstruct a protocol
 PICO search strategy
 The building blocks of a PICO search
 Use Embase to answer a well-developed prognosis PICO
question
 Summary
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4. DECONSTRUCT A PROTOCOL
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5. EBM Center Protocol: title page
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6. EBM Center Protocol: table of contents
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7. EBM Center Protocol: PICO question
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8. EBM Center Protocol: study eligibility
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9. EBM Center Protocol: exclusion criteria
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10. Protocol: search strategy
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11. PICO SEARCH STRATEGY
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12. PICO search strategy
A number of our PICO search strategies are comprised of three
sets of separate and distinct controlled vocabulary and natural
language terms:
• Terms for the health condition of the patient(s) or
population=P
• Terms for intervention(s)=I
• Terms for study type(s).

13. PICO search strategy : step by step
• Create P and I search strings.
• Use the Boolean operator AND to create a P&I search string set.
• Create a study specific search string or, if applicable, use a validated study
hedge.
• Use the Boolean operator AND to combine the study string set(s) with the P & I
set.
• Use the NOT Boolean operator to remove non-essential publication types and
animal studies.
• To reflect continuous updating, use the AND Boolean operator to add the ‘since
date’ search string to create the search of record.

14. PICO search strategy : caveat
Generally speaking, it is inadvisable to search on every
aspect of the clinical question within the confines of one
search strategy session.

15. THE BUILDING BLOCKS OF A PICO
SEARCH
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16. What’s in a name? Hedges; optimal filters; quality filters;
evidence-based filters=search strings
• Hedges and filters are search strings that contain controlled vocabulary
(EMTREE, MeSH, etc.) and natural language words and phrases.
• A validated hedge or filter contains both controlled vocabulary and natural
language words and phrases and has been put through a formal validation
process.
• Validated and un-validated hedges and filters are used to search for
American and British spelling of concepts and terms and to find incorrectly
indexed and e-pub ahead of print citations.
• Sets are created within the database interface when these hedges and
filters are used.
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17. Hedges and filters: +/∆
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+ ∆
Hedges, filters  Control
 Ensure retrieval of e-pub
ahead of print and online
first citations
 Incorrectly indexed
citations
 Complex and require
deep understanding of
basic & advanced search
techniques
 Require time to develop
 Require time to validate

18. Hedges, filters, & search term resources
McMaster University Health Information Research Unit (HIRU) Hedge Project:
http://hiru.mcmaster.ca/hiru/HIRU_Hedges_home.aspx
The InterTASC Information Specialists' Sub-Group Search Filter Resource:
https://sites.google.com/a/york.ac.uk/issg-search-filters-resource/
University of Pittsburgh MedTerm Search Assist:
http://www.hsls.pitt.edu/terms/
HLWIKI International: http://hlwiki.slais.ubc.ca/index.php/Filters_(ie._hedges)
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19. Question type Question definition Study methodology Embase study string
Diagnosis Diagnosis: the nature of
a disease; the
identification of an
illness.
Prospective, blind comparison
to a gold standard
(‘sensitivity and specificity'/de ) OR
(specificity:ab,ti )OR ('sensitivity and
specificity':ab,ti)
Prevention Prevention: to avert,
avoid or prevent the
onset of disease.
Randomized Controlled Trial
(RCT)
random*:ab,ti AND trial*:ab,ti OR
'randomized controlled trial'/de
Prognosis Prognosis: The forecast
of the probable outcome
or course of a disease;
the patient's chance of
recovery.
Prospective cohort; case-
control; case series
'incidence'/de OR 'mortality'/de OR
'follow up'/de OR 'prognosis'/de OR
'prediction and forecasting'/exp OR
'cohort analysis'/exp OR
incidence:ab,ti OR mortality:ab,ti OR
'follow up':ab,ti OR prognos*:ab,ti
OR predict*:ab,ti OR cohort:ab,ti
Embase: EBM Center’s study filters

20. Question type Question definition Study methodology Embase study string
Therapy /
Treatment
Therapy: the treatment
of disease. Therapy is
synonymous with
treatment.
Randomized Control Trial
(RCT)
(random*:ab,ti AND trial*:ab,ti) OR
('randomized controlled trial'/de)
Harms A measure of patient
safety considering
errors or mistakes
which result in harm to
the patient.
Observational studies;
nationally representative
prospective cohort studies
with multivariate adjustment
of adverse effects.
multivar*:ab,ti OR adjust*:ab,ti OR
'multivariate analysis'/exp
Embase: EBM Center’s study filters

21. Embase: systematic review/meta-
analysis filter
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('meta analysis'/de OR 'metaanalyses':ti
OR 'metaanalysis':ti OR 'meta analysis':ti
OR 'meta analyses':ti OR 'systematic
review':ti OR 'systematic review'/de OR
'cochrane database of systematic
reviews':jt)

22. Embase: publication types
We use this search string to NOT out specific
publication types:
'letter'/de OR 'editorial'/de OR 'note'/de OR 'short
survey'/exp
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23. Embase: animal studies
We use this search string to eliminate animal
studies from search results:
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NOT ('animals'/exp NOT 'humans'/exp)

24. Embase: ‘since date’ for citation
indexing
Search string to limit citations by a specific
indexing date:
[11-4-2011]/sd
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25. Prognosis PICO

26. EBM Center Protocol: Prognosis PICO question
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27. Protocol: search strategy
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28. 28

29. Prognosis PICO: P search strings
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30. Prognosis PICO: P & I search stings
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31. Prognosis PICO: study filter
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32. Prognosis PICO: NOT publications,
NOT animal studies and final results
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Search conducted on 7 April 2015

33. Prognosis PICO : combined harms, prognosis study
and systematic review/meta searches
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Search conducted on 21 April 2015

34. Prognosis PICO: study search of
record
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'community acquired infection'/de OR 'community acquired
infection':ab,ti OR 'community acquired disease':ab,ti AND
('pneumonia'/exp OR pneumonia:ab,ti) OR 'community acquired
pneumonia'/de OR 'community acquired pneumonia':ab,ti AND
('pneumonia outcomes research team':ab,ti OR port:ab,ti OR 'smart-
cop':ab,ti OR 'a-drop':ab,ti OR 'pneumonia severity index'/de OR
'pneumonia severity index':ab,ti OR 'psi':ab,ti OR 'curb 65 score':ab,ti
OR 'scoring system'/de) AND ('incidence'/de OR 'mortality'/de OR
'follow up'/de OR 'prognosis'/de OR 'prediction and forecasting'/exp
OR 'cohort analysis'/exp OR incidence:ab,ti OR mortality:ab,ti OR
'follow up':ab,ti OR prognos*:ab,ti OR predict*:ab,ti OR cohort:ab,ti)
NOT ('animal'/exp NOT 'human'/exp) NOT ('letter'/de OR 'book'/de OR
'editorial'/de OR 'note'/de OR 'short survey'/exp) AND [7-4-2011]/sd

35. 35
Prognosis PICO: harms search of
record
'community acquired infection'/de OR 'community acquired infection':ab,ti
OR 'community acquired disease':ab,ti AND ('pneumonia'/exp OR
pneumonia:ab,ti) OR 'community acquired pneumonia'/de OR 'community
acquired pneumonia':ab,ti AND ('pneumonia outcomes research
team':ab,ti OR port:ab,ti OR 'smart-cop':ab,ti OR 'a-drop':ab,ti OR
'pneumonia severity index'/de OR 'pneumonia severity index':ab,ti OR
'psi':ab,ti OR 'curb 65 score':ab,ti OR 'scoring system'/de) AND
(multivar*:ab,ti OR adjust*:ab,ti OR 'multivariate analysis'/exp) NOT
('letter'/de OR 'book'/de OR 'editorial'/de OR 'note'/de OR 'conference
paper'/de OR 'short survey'/exp OR 'conference abstract'/it) NOT
('animals'/exp NOT 'humans'/exp) AND [7-4-2011]/sd

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Prognosis PICO : systematic review and
meta-analysis study search of record
'community acquired infection'/de OR 'community acquired
infection':ab,ti OR 'community acquired disease':ab,ti AND
('pneumonia'/exp OR pneumonia:ab,ti) OR 'community acquired
pneumonia'/de OR 'community acquired pneumonia':ab,ti AND
('pneumonia outcomes research team':ab,ti OR port:ab,ti OR 'smart-
cop':ab,ti OR 'a-drop':ab,ti OR 'pneumonia severity index'/de OR
'pneumonia severity index':ab,ti OR 'psi':ab,ti OR 'curb 65
score':ab,ti OR 'scoring system'/de) AND ('meta analysis'/de OR
'metaanalyses':ti OR 'metaanalysis':ti OR 'meta analysis':ti OR 'meta
analyses':ti OR 'systematic review':ti OR 'systematic review'/de OR
'cochrane database of systematic reviews':jt) NOT ('animal'/exp
NOT 'human'/exp) NOT ('letter'/de OR 'book'/de OR 'editorial'/de OR
'note'/de OR 'short survey'/exp) AND [7-4-2011]/sd

37. Summary
Work with your investigators to:
• Identify terms and preferred filter methodology.
Deconstruct a protocol:
• Select the important concepts expressed in the P and I
portion of the PICO question.
Develop search strings:
• Use controlled vocabulary and natural language words
and phrases of British and American derivation to
construct search strings.
Use validated hedges:
• When applicable to your specific clinical question.
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38. THANK YOU!
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