This document outlines the key stages in conducting a systematic review: (1) developing a focused research question using PICO (Population, Intervention, Comparator, Outcome), (2) creating a protocol that pre-specifies the review methods, (3) conducting a thorough search of relevant literature and extracting data from included studies, (4) analyzing the data and assessing study quality, and (5) writing a report that balances detail and readability while transparently reporting the review process and results. Conducting each stage systematically helps ensure a valid and reproducible review.

1. Key Stages in Systematic
Review

2. Question
• What do you want answered
• PICO
• Population
• Intervention
• Comparator (or Reference)
• Outcome

3. Question
In those suspected of having PCD [Population] what is the
effectiveness of nasal nitric oxide [Intervention] in diagnosing PCD
[Outcome] compared to those diagnosed by a combination of
genetic, high speed video and electron microscopy [Reference]

4. Questions
• Other examples could be –
• [Exposure] as a risk factor for [outcome] in [population]
• Different interventions and comparators such as models of
care/compound measure.

5. Protocol
• Important document the pre-specifies facets of the review
• Background (the why?)
• Question (PICO)
• Aims
• Search strategy (databases, search terms)
• Detailed inclusion/exclusion criteria
• Statistical analysis

6. Example of protocol

7. Scoping
• Often neglected step
• Is integral to the process
• Run “dirty searches” early on
• Test searches and documents

8. Searching
• Very important to capture all relevant literature
• May not necessarily get every piece of evidence (additional sources
etc.)
• However, properly specify so thorough but not excessive

9. Extraction
• Initial screening of titles/abstracts
• Full text review (look at inclusion/exclusion)
• Extract data from all included texts
• Extraction form should be pre-specified but can scope with few
papers

10. Analysis
• If other steps are done well, this is the easiest step
• Protocol should make it easy to decide what should be included and
what the quality of that evidence is
• May end up with no included studies – this is still a valid result

11. Write-up
• Balance between detail and making it readable
• Still need to have a main message and back this up
• Make use of supplementary files to show protocol, search results and
to be transparent about why evidence was included/excluded
• Meta-analysis can make paper more publishable but can draw
dangerous conclusions if done inappropriately – state why not
appropriate.