Thinking about your literature review?

As part of your PhD or Master’s thesis, you will probably have to write a literature review. A successful literature review will offer an analysis of the existing research in your field, demonstrating your understanding of the subject area and any gaps in current knowledge. It’s an essential step in the research process that may influence the direction of your study.

There are different approaches and methods to literature reviews, and you may have heard them described as narrative, structured, scoping or systematic.

This blog post will explain the different types of literature reviews and some of the main things you’ll need to know. Some of the main differences are:

Narrative literature review	Systematic or structured literature review
Provides background information or discussion	Attempts to answer a specific question from evidence in the literature
Doesn’t usually attempt to be exhaustive	Attempts to include all relevant studies
May not specifically aim to eliminate bias	Uses inclusion/exclusion criteria to avoid bias
Doesn’t document the search process in detail	Documents and justifies the search process rigorously to enable replication
Doesn’t explain why the studies included were selected	Applies quality control to ensure that only high quality articles are included

Types of literature review

A traditional literature review or narrative review is a critical review of the literature on a particular topic, usually taking a thematic approach. The aim is to identify key research, demonstrate an understanding of the subject, and evaluate the quality and relevance of the literature. It should help to find a unique angle on the topic, prevent duplication of previous research, and identify any errors or mistakes to avoid. It will not be exhaustive and will probably have uncontrolled bias.

A structured literature review involves bringing many research studies together to answer a clearly formulated research question. It does not involve primary research, such as creating surveys and questionnaires. A structured review typically does not fulfil all the criteria of a full systematic review but may take a similar approach, following a set protocol for determining the research studies to be included and documenting every stage. The results and conclusions are based on the evidence found, not on the author’s own views.

A positioning study or scoping study is designed to help identify the scope of a topic before conducting a systematic review. It can indicate where proposed research fits with the existing literature and identify key concepts. A positioning study can help to focus a research topic, supporting a strong understanding of the field.

A systematic literature review is a specific research methodology to identify, select, evaluate, and synthesise relevant published and unpublished literature to answer a particular research question. The systematic literature review should be transparent and replicable, you should follow a predetermined set of criteria in your protocol to select studies and help minimise bias. The process will need to be documented throughout. A systematic literature review protocol may be registered, so that others can discover and minimise duplication, and can take several years to complete.

Defining a research question

You will probably have an idea of a research topic that you would like to investigate. Make sure that you chose an area that interests you as you will be spending a lot of time on it!

A good starting place is to run a scoping or exploratory search. This should give you an overview of the key issues, helping you to discover how much research exists and develop your aims and objectives. It should also help you to identify any key authors or subject terms. Depending on what you find you may need to amend your research topic.

Once you have decided on your topic you will need to determine your research question. Your question should be clear and focused, but also answerable and searchable. A well formulated question provides the foundations for good research.

Searching for literature

You will need to carry out in-depth searches to find relevant and quality literature for your literature review, using keywords and search strings. Our Librarians can help with this.

Most high-quality, scholarly research is published in academic journals. Cranfield has access to nearly 200 databases, containing journal articles and other scholarly publications.

You may also find useful information in grey literature, including documents not produced by traditional commercial or academic publishers, such as books, theses, conference papers, reports and working papers.

Academic searching is different to everyday searching. Often the questions are complex and do not have a simple answer. Searching and finalising keywords and search strings is an iterative process that takes a lot of time.

Your search will generate many results. Not all the articles retrieved will be relevant. If you are conducting a systematic literature review, after removing the duplicates you will need to filter your initial results by screening the titles and abstracts, and then the full text, against your inclusion and exclusion criteria, before the quality appraisal, which is the final step in the screening process.

Writing your literature review

When you have identified the studies you are going to use, you need to read them thoroughly to identify the main themes. The discussion should be structured around the themes, and what the literature you have found demonstrates. Every article does not need to address every theme, but each article you choose should cover at least one of your themes.

Do not simply describe each study without relating it to the themes or the other literature. Your literature review should give an overall picture of the topic, as shown in the material you have found.

Further information

For more extensive, detailed information about this topic, please see our Conducting your literature review pages on the Library Services website. We also have a range of additional support for writing systematic literature reviews in a series of blog posts.

Finally, please don’t forget that our librarians are more than happy to help with any questions you may have. Please get in touch with us!

 

Image by Tung Lam from Pixabay.