Search Strategy
SYSTEMATIC REVIEWS:
INFORMATION SKILLS COURSE

Outline / content
1) Introduction
2) Planning The Search Process
- Sources of Systematic Review
3) Constructing the Search Strategies
- Structure of the Search Strategy
4) Managing Your Search Result
5) Demonstration/Practical (How to Search Systematic
Reviews in The Cochrane Library, EBSCOhost & OVID)

Learning Outcomes / Objectives :
At the end of this session, you will be able to:
• Describe the purpose of a systematic review
• Select databases that can be used to do comprehensive searching
using Boolean and truncation searching
• Use PICOS technique to develop literature search strategies
• Manage the searching results using Reference Manager

1. Introduction
Definition of Systematic Review:
Cochrane Collaboration definition:
A systematic review uses systematic and explicit methods to
identify, select, critically appraise, and extract and analyze
data from relevant research [Higgins & Green 2011].
They involve a systematic search process to locate studies
which address a particular research question, as well as a
systematic presentation and synthesis of the characteristics
and findings of the results of this search.

Why we need systematic reviews
• Minimise the impact of bias/errors
• Can help to end confusion
• Highlight where there is not sufficient
evidence
• Combining findings from different studies
can highlight new findings
• Can mitigate the need for further trials

Sources of Systematic Review
1. Bibliographic databases
Type of database Description Database
1. Bibliographic
Databases
A database of bibliographic
records, an organized digital
collection of references to
published literature, including
journal and newspaper articles,
conference proceedings, reports,
government and legal
publications, patents, books, etc.
CENTRAL (Cochrane Central
Register of Controlled Trials)
MEDLINE
EMBASE
Trip Database
Scopus
Web of Science
2. Other sources
Subject specific databases/ Evidence-
based database
CINAHL
PsycINFO
UpToDate
3. Unpublished and
ongoing studies
Unpublished works are those which
have not been distributed in any
manner.
ClinicalTrials.gov, WHO ICTRP
(International Clinical Trials
Registry Platform)

Sources of Systematic Review
1. Bibliographic databases
Database URL Topic Coverage
Pubmed http://www.ncbi.nlm.nih.gov/pubmed Biology, Medical & Health
Sciences
MEDLINE PubMed/OVID/EBSCOhost
Access via PPUKM Library Portal
http://lib.hukm.ukm.my
Biology, Medical & Health
Sciences
The Cochrane
Library
(CENTRAL)
http://www.cochranelibrary.com Databases of systematic
reviews & other evidence
synthesis.
Trip Database http://www.tripdatabase.com Evidence-based healthcare
resources

Database URL Topic Coverage
Scopus www.scopus.com/scopus/home
.url
Life Sciences ; health Sciences
Web of
Sciences
isiknowledge.com Science Citations Index
EMBASE http://www.embase.com Biomedical ; emphases on drugs and
pharmaceutical. Health sciences database
with a slightly European perspective but
overlaps with PubMed. Especially strong for
drug information
Sources of Systematic Review
1. Bibliographic databases

Sources of Systematic Review
2. Other sources
Database URL Topic Coverage
UpToDate https://www.uptodate.com/
(UpToDate Anywhere. Apps is available for
Android and iOS)
Access via PPUKM Library Portal
http://lib.hukm.ukm.my
Evidence-based point of care
BMJ Best
Practice
http://bestpractice.bmj.com/ Clinical decision support
CINAHL EBSCOhost Medical
(http://search.ebscohost.com)
Nursing & Allied Health
Cumulative Index of Nursing
and Allied Health Literature.
PsycINFO EBSCOhost Medical
(http://search.ebscohost.com)
Psychological literature
Mental health citation
database.

Sources of Systematic Review
OTHER BIBLIOGRAPHIC DATABASES:
 national and regional databases
eg: KoreaMed, LILACS
 subject specific databases
eg: AMED, PsyINFO
 dissertation databases
eg: Dissertations & Theses
 grey literature databases
eg: openGrey, NTIS

Sources of Systematic Review
UNPUBLISHED AND ONGOING STUDIES:
 very important to minimise bias
 trials registers
 national and international
- ClinicalTrials.gov, WHO ICTRP
 subject-specific
 Pharmaceutical industry
 Regulatory agencies (eg: FDA, EMA)
 contact colleagues, organisations, other known
researchers

Structure of the Search Strategy
P I C O S
Patient,
Population or
Problem
Intervention or
exposure
Comparison Outcome Study Design
What are the
characteristics
of the patient
or population?
What is the
condition or
disease you are
interested in?
What do you
want to do with
this patient (e.g.
treat, diagnose,
observe)?
What is the
alternative to
the intervention
(e.g. placebo,
different
drug, surgery)?
What are the
relevant
outcomes (e.g.
morbidity,
death,
complications)?
 Meta
analysis
 Systematic
Review
 Randomized
Control trials
2. Constructing the Search Strategies

Example of a clinical question that outlines the PICOS components:
Helmets for preventing head and facial
injuries in cyclists
P I C O S
Patient,
Population or
Problem
Intervention or
exposure
Comparison Outcome Study Design
? ? ?
• To find 2 or 3 most important concepts
• Focus on those most likely to be found in title and abstract
Structure of the Search Strategy

P I C O S
Patient,
Population
or Problem
Intervention
or exposure
Comparison Outcome Study
Design
Cyclists Helmets Systematic
review
Helmets for preventing head and facial
injuries in cyclists

Broadening search term/keyword
1. Aim for high sensitivity
- express each concept in as many way as possible
- minimise the risk of missing a relevant study
- will lead to lower precision – find a balance
2. Use both text words and controlled vocabulary
3. Preliminary searching may help your test strategy
4. Strategies must be translated for every database or
interface

Text words
 Words appearing in title and/or abstract of the record
 Include synonyms, related terms, opposites,
international terms, alternative spellings, plurals
e.g. brain injury, head injury, skull fracture
 Truncation and wildcards: * $ ?
- protect* = protects, protective, protection
- but beware: car* = cars (but also carcinoma)
 Proximity operators – NEAR, NEXT, ADJ
e.g. liver ADJ3 cancer = liver cancer, liver and bowel
cancer
 Syntax must be translated for each interface

Controlled vocabulary
 Standardised subject terms assigned by indexes
- e.g. Medline = MeSH, Embase = EMTREE
- identifies relevant articles even if different terms
are used for the same concept
- ‘explode’ to include all narrower terms
- caution – indexers may not be subject experts, and
authors may not describe their study very well
 Check the terms applied to relevant papers for ideas
 Use database tools to map words to subject terms
 Controlled vocabulary must be translated for each
database

Controlled vocabulary

Controlled vocabulary
MeSH
Tree
Structures

Boolean Operators
OR – to expand search
bicycle helmetbicycle helmet
AND – to narrow search

Combining terms
Population
bicycl*
OR
cycling
OR
cyclist*
OR
bicycling
Intervention
helmet*
OR
Head
Protective
Devices
Study design
See
Cochrane
HSSS
AND AND

Limit & restrictions
 To avoid bias, do not limit by:
• language – ask your research group about
translation
• year – unless there is a clear point of change or
availability)
• format – may be additional information about a
study in letters

4. Managing your search results
 Store results from each source
• download all available fields for each record
• use bibliographic/reference management software
- e.g. EndNote, Mendeley, ProCite, Reference
Manager, RefWorks, Zotero
 Collate and de-duplicate

5. Demonstration/Practical (How to Search
Systematic Reviews in The Cochrane Library,
EBSCOhost & OVID)

Caffeine for daytime drowsiness

Searching for studies in The Cochrane Library
1. Open a web browser and go to www.thecochranelibrary.com

2. Click on Advanced Search. This will open the Advanced
Search page.

2. Click on Advanced Search. This will open the Advanced
Search page.

3. The Population for this review is people with drowsiness. In
the first row of the search field, enter drows*. This truncation
will find words such as drowsy and drowsiness.
Select Title,
Abstract or
Keyword Click Go

Medline in EBSCOhost Medical
http://lib.hukm.ukm.my

Medline in EBSCOhost Medical
MEDLINE Complete provides
authoritative medical information
on medicine, nursing, dentistry,
veterinary medicine, the health
care system, pre-clinical sciences,
and much more.

Medline in EBSCOhost Medical

Medline in EBSCOhost Medical
MEDLINE Complete provides
authoritative medical information
on medicine, nursing, dentistry,
veterinary medicine, the health
care system, pre-clinical sciences,
and much more.

Medline in OVID
http://lib.hukm.ukm.my

Medline in OVID

Medline in OVID

PubMed/Medline
https://www.ncbi.nlm.nih.gov/pubmed/

PubMed/Medline

PubMed/Medline

PubMed/Medline

Medline in EBSCOhost Medical

Topic :
Effectiveness of complementary therapy in helping to
stop people smoking
Concepts
Complimentary therapy, smoking
Databases :
CDSR, DARE, CENTRAL
Platform :
The Cochrane Library
Demonstration / Practical :

http://lib.hukm.ukm.my
Cochrane Library

MeSH in The Cochrane Library