Formulating a question for
systematic reviews
Jenny Basford, Systematic Reviews Support Librarian
mEsh
j.basford@qmul.ac.uk
The systematic review process
Formulate
research
question
Further selection of
primary studies
using inclusion
criteria
Extract data
Design
search
strategy
Write
protocol
Retrieve papers
Quality
Search
bibliographic
databases
Identify possible
papers from
titles/abstracts
Synthesis
appraisal
Formulate research /
policy conclusions
Learning outcomes
• To understand the importance and purpose of
setting out a well-formulated research
question
• To be aware of how bias can impact upon a
systematic review from the outset
• To be able to develop a clear review question
Introduction: formulating a review
question
• A statement of what you are going to do and
how you will do it
• Gives a clear pathway to follow for the rest of
the review
• Thus reduces bias and error
Creating a review question
• Comprised of two parts:
– ‘Free form’ question
– Structured question
Free-form question
• Defined by simple language
• Sometimes very vague
• Describes the query that you are interested in
– e.g. what effect does statin use have on pregnancy?
Creating a structured research
question: PICO(S)
•
•
•
•
•
Populations
Interventions
Comparators
Outcomes
Study design
Populations
• The group of participants/patients of concern
to the reviewer
• e.g. ‘all children under 16 years’; ‘men with
history of heart conditions’
Interventions
• Actions/exposures
• e.g. treatments, social or educational
interventions, risk factors, tests, drugs, surgical
techniques
• Refined by dosage/duration
• Can be broad, e.g. ‘dietary supplement’ or specific,
e.g. ‘Vitamin D, Cholecalciferol’
Comparators
• If including comparative studies: don’t always have
this
• Similar definition as intervention
• Comparison can be: no intervention, placebo,
current standard practice or an active
comparator: e.g. comparing accuracy of
ultrasound vs. MRI scan in diagnosis of
adenomyosis
Outcomes
• Clinical changes in health state, e.g. morbidity,
mortality, survival
• Health resource use
• Quality of life
• Behaviour
Study designs
• ‘major role in determining the reliability of the
results’ (CRD)
• RCTs usually the study design of choice for
effectiveness reviews
• Scoping search will help you decide whether
to limit by study type
• Depends entirely on the nature of your topic
‘Free form’ review question
To assess the impact of statin use in pregnant
women upon their unborn child
Structured review question: PICOS for
statins in pregnancy
Population:
pregnant women
Intervention:
statins
Comparator:
none
Outcome:
congenital malformations in the child
Study design:
RCTs
Conclusion
• Spending time on clearly defining your
question at the beginning will help your review
by providing a pathway and reducing bias
• It will ensure everyone on the review is asking
the same question