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Systematic reviews

What is a systematic review?

Systematic reviews, systematic searches and literature reviews – they all sound very similar. So, what’s the difference and how do you know which is the right choice for you? 

This page defines a systematic review and it’s features, explains how it differs from other types of reviews and searches, and advises how to pick a review appropriate for your purpose. 

What is a systematic review?

A systematic review is a type of research that analyses all the studies on a particular topic to find out what the evidence shows overall. 

To do this, researchers use explicit, systematic and tightly structured methods to analyse, appraise and synthesise all evidence available on a particular question. This is documented in advance with a protocol to minimise bias and arrive at a considered judgement or set of balanced conclusions. 

A systematic review can take several months to a couple of years to complete and often requires collaboration between a group of people. 

Originally developed for medical-related fields to support evidence-based practice, systematic reviews are increasingly being undertaken in other fields such as environmental science, business and social science. 

Watch this video to understand more about systematic reviews: 

Systematic reviews and literature reviews

Systematic reviews are often confused with literature reviews. They follow similar processes, but they are quite different. Systematic reviews take many months to complete, keep to strict protocol and need a thorough knowledge of the topic. Literature reviews are informal and non-specific, take less time and require a general overview of a subject.  

This table compares systematic reviews and literature reviews across several areas of the review process: 

  Systematic review Literature review
Definition

High-level overview of primary research on a focused question that identifies, selects and synthsises and appraises all high quality research evidence relevant to that question

Qualitatively summarises evidence on a topic using informal or subjective methods to collect and interpret studies

Goals

Answer a focused clinical question
Eliminate bias

Provide summary or overview of a topic

Question

Clearly defined and answerable clinical question
Recommend using PICO as a guide

Can be a general topic or a specific question

Components

Pre-specified eligibility criteria
Systematic search strategy
Assessment of the validity of findings
Interpretation and presentation of results
Reference list

Introduction
Methods
Discussion
Conclusion
Reference list

Number of authors

Three or more

One or more

Timeline

Months to years
Average 18 months

Weeks to months

Requirements

Thorough knowledge of topic
Perfom searches of all relevant databases
Statistical analysis resources (for meta-anaylsis)

Understanding of topic
Perform searches of one or more databases

Value

Connects practicing clinicians to high quality evidence
Supports evidence-based practice

Provides summary of literature on a topic

Credit: ‘What’s in a name? The difference between a systematic review and literature review and why it matters?’ by Lynn Kysh

Systematic reviews and systematic searches

For many assignments, dissertations or theses, you will be required to provide an overview of the literature on a research topic. While this requires a comprehensive and structured search of the literature, you will not be required to adhere to the strict methodology of a systematic review. 

Watch this video to learn more about systematic searching:

What type of review is appropriate for your purposes?

When planning your review, it is important to choose a methodology that matches the purpose of the review. 

Read more about choosing the right type of review:

The ‘Right Review’ tool can assist you in identifying which type of evidence synthesis would be appropriate for your research question.  

Recommended additional reading

Further your understanding of systematic reviews: