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Formulating a question for systematic reviews
Jenny Basford, Systematic Reviews Support Librarian
The systematic review process
Formulate research /
policy conclusions
Search bibliographi
c databases
Identify possible papers
from titles/abstracts
Retrieve papers
Extract data
Further selection of
primary studies using inclusion
criteria
Synthesi
s
Formulate
research question
Design search
strategy
Quality
appraisal
Write protocol
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
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 womenIntervention:
statinsComparator:
noneOutcome:
congenital malformations in the childStudy design:
RCTs