Formulating a question for systematic reviews

Jenny Basford, Systematic Reviews Support Librarian

mEshj.basford@qmul.ac.uk

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

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 womenIntervention:

statinsComparator:

noneOutcome:

congenital malformations in the childStudy 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