Systematic reviews aim to answer a specific research question by systematically locating and analysing all existing evidence on the topic. Systematic reviews are more rigorous and evidence-based than literature or narrative reviews, and often form the basis of evidence-based practice.
This guide provides information to researchers undertaking a systematic review, specifically addressing the process of searching for studies to include in your review.
The purpose of a systematic review is to answer a clear and focused question. The question should be the first thing you define in the process of beginning your systematic review, and should guide decisions around your inclusion and exclusion criteria, how you create your search strategy, how you collect data and how you present your findings. Questions may be broad or narrow in focus.
The PICO(S) model can be used to create your well built question.
|Population||Ask: How would I describe a group of patients similar to mine?
The patient, problem or situation.
|Intervention||Ask: Which main interventions am I considering?
Therapy, prevention, diagnostic testing, aetiology/harm.
|Comparison||Ask: What is the main alternative?|
|Outcome||Ask: What could this intervention accomplish, measure, improve or affect?|
||Ask: Which study design will best answer my question?|
Equal emphasis may not be put on each part of the PICO(S), and will largely depend on the topic of your systematic review.
The methodology that is used for your searching should be documented and included in some way as part of your final review (exact procols differ between journals). You should detail:
It may be useful to save your search strategies in the databases you use (where possible) to refer back to later. Resources such as Medline, EMBASE and Cochrane provide this feature.
Following are some examples of documented search methodologies:
The Faculty of Medicine, Dentistry and Health Sciences at UWA has created an online learning module called Answering Clinical Questions. This tutorial will walk you through the process of evidence based practice and will assist you to create a meaningful and answerable question for your systematic review using the concept of PICO. There are four modules in ACQ:
The following books may be useful further reading for those conducting a systematic review: