Secondary Data Analysis:
Systematic Reviews &
Associated Databases
Prof. Eileen Savage
OMCYA Keeping Children Safe Summer
School,
12th – 16th September 2011,
UCC.
What is a Systematic Review?
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a concise scientific investigation, with pre-planned
methods that summarise, appraise, synthesise and
communicate the results of multiple primary studies
(Cooke et al, 1997; Centre for Reviews and
Dissemination, 2008).
ie Research on Research with findings of existing data
becoming raw data
Differs from a narrative review/
traditional literature review
Traditional Review vs. Systematic Review
(Nasseri-Moghaddeam & Malekzadeh 2006)
Growth of Systematic Reviews
Systematic Reviews –
Origins of Growth
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Expanding volume of
published &
unpublished literature
Conflicting findings
across studies leading
to ‘uncertainty’
Contributes to
Evidence Based
Movement
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When to Do a Systematic Review
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When there is ‘uncertainty’ about the effectiveness
of interventions in practice
When key questions remain unanswered e.g. about
treatments, interventions, practices, experiences
etc…
To inform practice/policy with best available
research evidence
To identify what is known/not known in an area to
guide future research (includes research methods)
(Petticrew & Roberts 2007)
Where to find a Systematic Review
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Peer Reviewed Journals (search bibliography databases)
Cochrane Database of Systematic Reviews (Cochrane
Library; several Groups)
Database of Abstracts of Reviews of Effects (DARE)
Health Technology Assessment Database
NHS Economic Evaluation Database
The Campbell Collaboration Library (Groups e.g. Crime &
Justice; Education; Social Welfare; Methods; Communication &
internationalization; Users Groups.
The Evidence for Policy and Practice Information and Co-ordinating Centre
(EPPI-Centre), University of London. (Education; Health Promotion;
Employment; Social care; Crime and Justice)
Others
Structure of Systematic Review e.g.
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Introduction/Background
Questions/Aim & Objectives
Criteria for considering studies
Search Methods
Methods of the Review (e.g screening reading
papers; quality assessment; data extraction)
Results
Discussion
Conclusions
Criteria for Including/Excluding
Studies
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Types of Studies (see hierarchy of evidence)
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Types of Participants
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Types of Outcomes
Link to Questions being asked
Hierarchy of Evidence
Search Method
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Search Terms
Databases
+/- Hand searching
+/- Reference lists
+/-Grey Literature
+/- Contacting authors
(Refer to Booth et al on standards for Reporting Search Methods)
Search Strategy: CINAHL with Full Text
(EBSCO)
Date of Search
Years Covered
Complete Strategy
30th March 2011
Date of Search
January 1990 to March
Years Covered
2011
1. cystic fibrosis.TX.
2. mucoviscidosis.TX.
3. 1 or 2
4. clinical trial.PT.
5. trial.TX.
6. random*TX.
7. 4 or 5 or 6
8. educat*.TX.
Complete Strategy
9. program*TX.
10. 8 or 9
11. self care.TX.
12. self-care.TX.
13. selfcare. TX.
14. self management.
TX.
15. selfmanagement.TX.
16. manag*.TX.
17. 11 or 12 or 13 or 14
or 15 or 16
18. 10 or 17
Search Strategy: Embase (Elsevier)
30th March 2011
January 1990 to March 2011
1. cystic fibrosis. ti,ab,de.
2. mucoviscidosis. ti,ab,de.
3. 1 or 2
4. 'clinical trial'. ti,ab,de.
5. 'trial'. ti,ab,de.
6. random*'. ti,ab,de.
7. 4 or 5 or 6
8. educat*. ti, ab, de.
9. program*. ti,ab,de.
10. 8 or 9
11. self care ti, ab, de.
12. selfcare. ti,ab,de.
13. self management. ti, ab,de
14. manag*. ti, ab,de.
15. 11 or 12 or 13 or 14
16. 10 or 15
17. 3 and 7 and 16
Methods – Screening for Inclusion/ Exclusion
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Titles & Abstracts – In/Unsure/Out
Read in full –> in/unsure /out
Quality Assessment of Individual
Studies
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Quality threshold for inclusion ie exclude
poor quality studies
Assessment of Quality may be part of SR
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How
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- No –’gold standard’ exists
- Checklists available e.g. CASP
- Quality Scales/Criteria
Data Extraction
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Use a data extraction form (s)
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2 or more reviewers / cross-check
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Extract details relevant to Questions/
Objectives
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Present raw data in report – table format
Data Analysis & Synthesis
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Collation & summary of results
Present in tabular form/forest plots/other +
descriptive narrative account
+/- Meta-analysis, if appropriate (not possible
with heterogeneity ie cannot pool apples with
oranges for the purpose of statistical analysis
as one data set)
Results, Discussion, Implications
Critical Appraisal of Systematic
Reviews
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The PRISMA Statement: standards for
reporting SRs & Meta-analyses
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Critical Appraisal Tool Kit for SRs (CASP)
Website on Critical Appraisal
Tools (covers a range of methods)
At:
Division of Health Sciences
International Centre for Allied Health Evidence
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http://www.unisa.edu.au/cahe/Resources/CAT/d
efault.asp
References
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To follow