Skip to Main Content
Library Guides

Systematic Reviews

What is a systematic review?

A systematic review is a firmly structured literature review, undertaken according to a fixed plan, system or method. As such, it is highly focused on a particular and explicit topic area with strict research parameters. Systematic reviews will often have a detailed plan known as a protocol, which is a statement of the approach and methods to be used in the review prior to undertaking it.

Systematic review methodology is explicit and precise because it aims to minimise bias, thereby enhancing the reliability of any conclusions. It is therefore considered an evidence based approach. Systematic reviews are commonly used by health professionals, but also policy makers and researchers.

There is information about the difference between a systematic review and a literature review below. If you are undertaking systematic approach to a literature review, however, you might find certain aspects of this guide useful.

Literature review Vs. systematic review

You can find further information on literature reviews on the literature reviews guide:

Literature review Systematic review

Topic areas and research questions can be broad. There might be multiple areas of research focus. The research areas or questions may have a focus around a particular viewpoint or in support of a theory or existing body of knowledge.

Begins with a focused, well-defined and precise question. All the evidence, research or material should be found to answer the specific question.


A literature search may not always be comprehensive in scope. Searches may be undertaken using one or many sources, but not necessarily in a specific order.  A rigorous search plan may not be employed and search results may be selected subjectively. 

Searching is comprehensive in scope. It aims to find all the published and unpublished literature from a wide variety of sources in both print and electronic format.

There may not necessarily be a clear rationale as to why specific research has been included in the review.

Clear reasons for including or excluding studies are documented and informed by the research question.


Individual studies are not always assessed for their quality and each study might not be assessed according to the same standards every time.

Individual studies within the review are assessed on their quality (how well they were conducted) and objectivity.


A written report on search methodology and results is often not included, but where it is it will often not contain the same level of detail as that found in a systematic review.

Search methodology and search results are clearly articulated, so that the search can be replicated by others. Tables and charts are often used to document the search process.


Conclusions might not be based on the included studies, but rather build on original primary research or the researchers prior knowledge.

Clear conclusions can be made from the studies for  recommendations for practice or further research.

Additional resources

Reproduced and adapted with kind permission of Manchester Metropolitan University