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Doing a systematic review

Guidance on the steps involved in doing a systematic review, and ways in which the Library can help.

Creating a protocol

Light bulb in a thought bubbleYour first step is to devise a focused, clear question which your review will address. You then need to develop a protocol which outlines the study methodology including:

  • background
  • research question and aims
  • criteria for inclusion and exclusion
  • methods including:
    • search strategy
    • selecting studies for inclusion
    • quality assessment
    • data extraction & analysis
    • synthesis of results
    • dissemination
  • time frame.

You may wish to do some scoping searches of relevant databases to find out how much has been written, and what limits you should apply.

PICO framework for structuring your research

There are several different frameworks you can use to help structure your research and ensure you have clear parameters for your search. The most commonly used one used for health-related reviews is the PICO framework:

  • Population
    This could be the general population, or a specific group defined by: age (e.g. infants, children, adolescents, elderly); socioeconomic status (e.g. low-income, homeless); risk status; location (rural or urban)
  • Intervention
    Refers to the therapy, test, strategy to be investigated (e.g. drug, behavioural change, environmental factors, counselling)
  • Comparator
    A measure you will use to compare results against (e.g. no treatment, alternative treatment/exposure, standard/routine interventions)
  • Outcome
    What outcome is significant to your population or issue? This may be different from the outcome measures used in the studies.
PICO example
Review title The effect of blueberries on cognition and mood: a systematic review of human intervention trials
Population Individuals of all ages, without regard to gender, race or ethnicity. 
Intervention Supplementation with blueberries, relevant blueberry products or extracts from blueberries. This may include freeze-dried blueberries, blueberry concentrate, or blueberry juice.
Comparator Placebo or control groups.
Outcome Changes in cognitive function based on cognitive screening measures (such as Mini mental state examination, Montreal Cognitive Assessment), neuropsychological interview, informant/carer responses to assessment tools or changes in mood. Secondary outcomes include: changes in biochemical levels in biological fluids. Of particular interest are inflammatory markers, cardiovascular disease risk factors, and markers of gastrointestinal health. 

This example is extracted from: PROSPERO 2018 CRD42018100888.

Further information

Alternative frameworks

Another framework may be more suitable depending on your review topic. Here are some other options:

  • PECO – Population | Environment | Comparison | Outcome
    Very similar to PICO but looking at the effect of exposure to something e.g. smoky atmosphere
  • SPICE - Setting | Population | Intervention | Comparison | Evaluation
    Another variant of PICO but this time including the setting (where? in what context?)
  • CIMO - Context | Intervention | Mechanisms | Outcome
    A variant of PICO suitable for management and organisation studies
  • ECLIPSE - Expectation | Client group | Location | Impact | Professionals | SErvice
    Recommended for health policy/management searches
  • SPIDER – Sample | Phenomenon of Interest | Design | Evaluation | Research Type
    Developed to create effective search strategies of qualitative and mixed-methods research - more specific than PICO/PECO
Further information