A systematic literature review is a method to review relevant literature in your field through a highly rigorous and 'systematic' process. The process of undertaking a systematic literature review covers not only the content found in the literature but the methods used to find the literature, what search strategies you used, and how and where you searched. A systematic literature review also, importantly, focuses on the criteria you have used to evaluate the literature found for inclusion or exclusion in the review. Like any literature review, a systematic literature review is undertaken to give you a broad understanding of your topic area, to show you what work has already been done in the subject area, and what research methods and theories are being used. The literature review will help you find your research gap and direct your research.
A literature review "...creates a firm foundation for advancing knowledge. A successful literature review facilitates theory development, closes areas where a plethora of research exists, and uncovers areas where research is needed" (Webster & Watson, 2002, p.8). Fink (2014, p.3) describes a systematic literature review as a "systematic, explicit and reproducible method for identifying, evaluating and synthesizing the existing body of completed and recorded work produced by researchers, scholars and practitioners".
The purpose of your literature review will be to build a knowledge base for your research. The knowledge base will help direct your research, assist with research gap analysis, and give you a strong platform to direct original research to address any gaps and support your hypothesis.
A systematic literature review differs from other styles of literature review as it applies a much higher level of methodology to the process. The EPPI-Centre is a research centre at the University College London. They state the key features of a systematic literature review are:
Systematic literature reviews aim to find as much relevant research on a particular research question as possible, by using explicit methods to identify what can reliably be said on the basis of these studies. Methods should be explicit and systematic with the aim of producing varied and reliable results. In this way, systematic reviews reduce the bias that can occur in other approaches to reviewing research evidence (EPPI 2015).
There are three principal reasons to undertake a systematic approach to literature reviews: clarity, validity and auditability (Booth, Papaionannou & Sutton 2012).
A focused research question and explicit search strategies help to clarify considerations of scope and terminology (Booth, Papaionannou & Sutton 2012, p. 23).
In this case, clarity means that the review should have a defined structure, document methods and document the searching process. This will allow for easy navigation and interpretation of the literature search. It will also allow others to understand what you have done and why certain research materials have been included while others have been excluded. It is recommended that you are very clear in what you are trying to achieve with your literature review. Keep the review focused and show each step of your methodology so the reader can follow your arguments and see where you are going and why.
For a literature review to be a valid research output, it should seek to be unbiased regarding the literature that is reviewed. When crafting a literature review you need to be mindful to include a range of voices to show clear reasoning behind the inclusion of particular papers and theories. Pitfalls to be aware of and/or avoid in your review process include:
To avoid publication bias, be sure to search a wide range of resources for the materials you include in your literature review.
Auditability, a key feature of a systematic literature review, pertains to the keeping of accurate records of your systematic search strategies. Accurate record keeping of your search strategies will allow others to verify your results. The records will give the reader an understanding of how you came to find and choose the materials in your review. It will give your review an extra layer of authority. Auditability is a crucial part of the review process. The review must be consistent and systematic throughout.