This webinar introducing participants into the basics of searching and selection of studies for systematic reviews.

1. Selecting Studies
Moriam Chibuzor

2. Conflicts of Interest
 I wish to disclose that I am affiliated with Cochrane
Nigeria, a body whose focus is the production and
dissemination of systematic reviews

3. Outline
• Eligibility Criteria
• Eligibility screening form/checklist
• Who will screen: Points to Note
• Steps in Screening
• Resolving Conflicts in Screening
• Support Tools for screening
• Documenting the Process – PRISMA flow diagram
• Reporting the process (multiple reports, excluded studies, studies
awaiting classification

4. Steps for conducting a Systematic Review
1. define the question
2. plan eligibility criteria
3. plan methods
4. search for studies
5. apply eligibility criteria
6. collect data
7. assess studies for risk of bias
8. analyse and present results
9. interpret results and draw conclusions
10. improve and update review

5. Eligibility Criteria
Clinical question (PICO format)
Types of studies that answer the
question

6. QUIZ
 What does
PICO Stand for?
“Thinking man” licensed under CC BY 2.0 retrieved from publicdomainspictures.net

7. P
I
C
O
Intervention
Population
Comparison
Outcome

8.  P- participants
 I- intervention Eligibility criteria
 C- comparison
 O- outcome not usually part of the criteria

10. Outline
• Eligibility Criteria
• Eligibility screening form/checklist
• Who will screen: Points to Note
• Steps in Screening
• Resolving Conflicts in Screening
• Support Tools for screening
• Documenting the Process – PRISMA flow diagram
• Reporting the process (multiple reports, excluded studies, studies
awaiting classification

11. Eligibility screening form/checklist
 Develop eligibility screening
form/checklist to guide screening of
studies
 Based on eligibility criteria
(population, intervention, comparator,
study design)
 Pilot the form using some studies
 Include studies that appear to be
included, excluded and unclear
 Revise form as needed

13. INCLUDE EXCLUDE UNCLEAR

14. Outline
• Eligibility Criteria
• Eligibility screening form/checklist
• Who will screen: Points to Note
• Steps in Screening
• Resolving Conflicts in Screening
• Support Tools for screening
• Documenting the Process – PRISMA flow diagram
• Reporting the process (multiple reports, excluded studies, studies
awaiting classification

15. Who will screen:
Some points to Note
 Screening should ideally be completed in duplicate
 By two persons
 Independently
 Some exceptions:
 Rapid Reviews
 Title and abstract screening (in some cases)
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16. Outline
• Eligibility Criteria
• Eligibility screening form/checklist
• Who will screen: Points to Note
• Steps in Screening Studies
• Resolving Conflicts in Screening
• Support Tools for screening
• Documenting the Process – PRISMA flow diagram
• Documenting/Reporting the process (multiple reports, excluded studies,
studies awaiting classification

17. Steps in Screening Studies
 Title and Abstract Screening
 Examine titles and abstracts
 Remove obviously irrelevant Studies
 Be inclusive at this stage
 Studies assessed as include or unclear pass onto full text screening
 Full text screening
 Obtain full text article for study
 Examine full text for compliance with eligibility criteria
 Contact Study author/investigator for Studies that are unclear
 NB: Link together multiple reports of Same study (Same trial registration,
authors, settings etc)

18. Quick Quiz
 How can we resolve conflicts when screening studies for a systematic review?
a) By voting
b) By discussion and consensus
c) The lead author decides
d) Arbitration by an independent team member
e) B and D when screeners cannot reach consensus

19. Resolving Conflicts in Screening
• Discussion & Concensus
• Arbitration by a third review
author
• If no resolution
• Contact study authors for more
information
• Classify study as awaiting
classification
“Conflict” licensed under CC BY 2.0 retrieved from publicdomainpictures.net

20. Support Tools for Screening
 What tools do you know
that can be used in
screening for systematic
reviews?
“Light question-mark-thought-bulb-with-icon” licensed under
CC BY 2.0 retrieved from freepngimg.com

21. Systematic Review Toolbox
systematicreviewtools.com

22. Author support tools
 Covidence
 for intervention reviews
 www.covidence.org

23. Author support tools
 EPPI-Reviewer
 for all types of reviews
 including complex, non-randomised
and qualitative reviews
 https://eppi.ioe.ac.uk/cms/

24. Documenting /Reporting the Process

25. PRISMA Flow Diagram

26. PRISMA Flow Diagram
http://prisma-statement.org/prismastatement/flowdiagram.aspx

27. PRISMA Flow Diagram

28. Documenting /Reporting the Process
excluded studies
• Results section
 Search results
 Number Identified
 Number excluded at each stage
• Characteristics of excluded studies table
 Contains excluded studies with primary reason for
exclusion
 Only list studies that may appear to meet
the eligibility criteria, but on closer
inspection do not
 Or studies that are well known, appear
eligible and which readers would expect to
be included
• Studies awaiting Classification

29. Putting it to practice
 Consider the following Systematic Review Title:
Vitamin D, calcium or a combination of vitamin D and calcium for the
treatment of nutritional rickets in children
 Participants: Children 0-18 years with nutritional rickets
 Study Design: Randomized Controlled Trials
 Intervention/Comparisons
 Calcium versus Vitamin D
 (Calcium + vitamin D) versus Vitamin D
 (Calcium + vitamin D) versus Calcium

30. Putting it to practice

31. Putting it to practice

33. THANK YOU

34. QUESTIONS
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