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Food and nutritional sciences research project guidance: Doing your literature review

Resources and links to guide you through your research project.

All projects will include a literature review:

  • In a lab-based project the review may just be part of the introduction helping to outline the state of the knowledge and gap you are trying to address.
  • For literature-based projects this will be the bulk of your discussion, although the way your report is structured will depend on the type of review you are doing. If you are doing a systematic review you will need to follow a specific protocol for writing it up. See 'Doing a systematic literature search' for guidance and links.
This pages gives general guidance on writing a literature review, but you should talk to your supervisor about the type of review you are expected to write.

Getting started

A literature review sets up your project and positions it in relation to the background research. It also provides evidence you can refer back to later to help interpret your own results. When getting started on your literature review, it helps to know what role this plays in your overall project.

A literature review:

  • Provides the background / context to your topic
  • Demonstrates familiarity with previous research
  • Positions your study in relation to the research
  • Provides evidence that may help explain your findings later
  • Highlights any gaps in the research
  • Identifies your research question/s

In your literature review you should include:

  • Background to the topic (e.g. general considerations, mechanisms of formation, analytical techniques, etc…)
  • Why it is important (e.g. food with improve flavour, less carcinogens, more taste, less processed foods, new probiotics ......... & etc.)
  • What research has been performed and what has been found out
  • The specific area you are interested in (e.g. cheese, snacks, fruits, ….)
  • Current ideas and hypotheses in this area
  • The key research questions which remain

This means your literature starts out relatively broad but soon narrows to be focused more specifically on your own research question. You can think of it like a funnel-shape:

It can seem difficult to know where to start with your literature review, but to a certain extent it doesn’t matter where you start…as long as you do!

If you like understanding the bigger picture and seeing the whole of an idea before getting into the detail – try starting with a general text and then using the bibliography of this to find more specific journal articles.

If you like to start small with one idea or study, find a relevant journal article or single study and then build up by trying to find related studies and also contrasting studies.

Further help

For more on this view the video tutorial on the other tab in this box, or take a look at these study guides:

Note-taking

A key to a good literature review, is having a good system for recording and keeping track of what you are reading. Good notes means you will have done a lot of the thinking, synthesising, and interpreting of the literature before you come to write it up and it will hopefully make the writing process that bit smoother. Systematic note-taking will also ensure you have all the details you need to write your references and won’t accidentally plagiarise.

Have a format for recording your notes that suits you – whether this is in a table, bullet points, spider diagrams, using a programme like Evernote, or in a traditional notebook! 

Tables can be a useful way of recording notes for a literature review as it enables you to compare and contrast studies side-by-side in the table. It also forces you to write a concise summary or it won’t fit into the table!  

e.g.  A suggested outline for a note-making table

Full reference Aims of study (what are they trying to find out?) Brief summary of methods Summary of key findings Overview of what the findings mean Strengths / weaknesses of the study
           
           

Have a system for distinguishing quotations and your own words – you don’t want to accidentally include something only to discover it was someone else’s words and you may have plagiarised by mistake. Always make sure your quotation marks are clear in your notes (it is easy to miss them in a hurry) and it really helps to record the page number of any direct quotation so you can go back to check easily.

Avoid the temptation to copy out text – copying out large chunks of text is slow and also means you tend not to process and understand what you copy. Summarising and writing short phrases instead means you are likely to have a better understanding and will remember it and be able to use your notes more easily later. 

Summarise – writing a short summary or overview of what you have just read helps you to clarify their argument and position. It also means you have a handy short reminder when you come back to it later – you don’t want to be re-reading notes that are as long as the original text in the first place!

Always record the full bibliographical details – it only takes a few moments to write down everything you need for your reference. You may think it is fine to leave it as you will be able to find these details later…but you probably won’t and you will waste time searching for them when your deadline is fast approaching.

A top tip if you find it hard to put things in your own words – try reading a longer section of the text before taking notes. It is very difficult to paraphrase something line-by-line as you go along, because everything seems important and it is too easy to just lift the phrases the author has used. Reading a longer section will give you a better overview and fuller understanding, meaning you can choose what is important and relevant to your own project. 

Further help

For more on this watch the video tutorial on the other tab in this box, or take a look at these study guides:

Referencing and avoiding plagiarism

It is a good idea to keep your references up to date as you write so that you know exactly where each idea comes from (and it will save a tedious job at the end ).

Make sure you reference every idea that comes from another source, which includes things like images, diagrams, and statistics, not just word-for-word quotations.

Use the referencing style detailed in the 'Referencing' page in this guide and stick to it consistently! Don’t switch between styles or formats. It may seem petty, but meticulously formatted referencing shows you have taken care in your work and have a professional academic approach (and it will get you marks!). You could consider using a reference management tool, such as EndNote Online, for storing your references and inserting them into your report (see the 'Referencing' page) - this will be essential if you are doing a literature-based project or a systematic review.

A top tip is to have a proof-read through for referencing only – print out your literature review as it is easier to spot mistakes on paper than on screen.

Referencing checklist

  • Is every idea from another source referenced?
  • Does every word-for-word quotation have quote marks and is referenced?
  • Are all paraphrases in your own words (not just changing a few words) and referenced?
  • Does every in-text reference match a full reference in the bibliography?
  • Are all names and titles in the references spelled correctly?
  • Have you followed the department’s preferred referencing style consistently?

Further help

For more on this watch the video tutorial on the other tab in this box.

For detailed help on citing references see the Referencing page in this guide:

Structuring your review

A literature review compares and contrasts the research that has been done on a topic. It isn’t a chronological account of how the research has developed in the field nor is it a summary of each source in turn like a ‘book review’. Instead a literature review explores the key themes or concepts in the literature and compares what different research has found about each theme.

Use sub-headings to structure your literature review as this helps you group the different studies to compare and contrast them and avoids a straight chronological narrative.

To help find your sub-headings:

  • Brainstorm all the different concepts or themes in the research that relate to your topic or title
  • Identify the ones that are important to your research question – think of what the reader needs to know about to understand the different aspects of your project
  • Place the themes in an order that would make sense to your reader – usually going from broad themes to themes more directly related to your project (see funnel diagram in Getting started)
  • Turn these into sub-headings
  • Use these sub-headings as an outline plan for your literature review – what will come under each sub-heading

Below is an example structure of a literature review that starts broad and starts to narrow by linking the concepts that are specific to this project:

Title: Cardiovascular Disease and Sweet Bell Pepper

Cardiovascular Disease

  • Carotenoids and CVD
  • Ascorbic acid and CVD
  • Flavonoids and CVD

Sweet Bell Pepper

  • Vitamins and Phytochemical Composition of Bell Peppers
  • Vitamins and Phytochemical Composition of Bell Peppers at Different Maturity Stages
  • Colour of Bell Peppers and Antioxidant Activity

Further help

For more on this see the following study guide:

Writing the literature review

When writing a literature review, you want to be comparing and contrasting the studies to build up a picture of what the research says about your topic.

This means you should be using comparative and evaluative language more than descriptive language:

Descriptive language Comparative language
Linear Uses comparative words
Chronological Uses evaluative words
This happened... then this happened Linking words
Unconnected sentences Sentences which qualify and build on each other
Makes statements but doesn't explain them Uses details & examples to explain statements
Similar sentence construction Varied sentence construction
Boring writing Interesting writing

Example:

"Green (2005) discovered …."

"In 2011, Black conducted experiments and discovered that …."

"Later Brown (2015) illustrated this in ……"

Example:

There seems to be general agreement on x, (see White 1995, Brown 2015, Black 2011, Green 2005). However, Green (2005) sees x as a consequence of y, while Black (2011) puts x and y as …. While Green's work has some limitations in that it …., its main value lies in …."

For more examples of the kinds of comparative and evaluative language used in literature reviews see:

Be selective

Also you want to be selective in how you refer to the literature. In a literature review, you don’t have to refer to each study in the same depth. Think of the points you want to make and then include just enough detail about the study to provide evidence for this. For example, you don’t have to analyse the strengths and weaknesses of the methodology for each study in depth, you only need to do this if you are making a point which relates to the methodology or a point about the findings which depends on the methods being robust and valid (e.g. the authors claim there are wide-spread applications of their trials, but they have used a very small sample size, which suggests they can’t make such a bold assertion). 

For example - the summary below maps out the state of current research and the positions taken by the key researchers. A significant amount of reading and in-depth understanding of the field has gone in to being able to summarise the research in these few sentences.

Many studies have investigated household accidents caused by cheese. These studies disagree about the most significant reasons for cheese-based injury with some arguing that choking on cheese poses the highest risk (Muffet, 2008; Moon; 2009; Rennet, 2011). Other studies claim that burns from melted cheese are more hazardous (Rechaud, 1989; Rarebit, 2009), whilst a minority of recent studies have identified slipping on cheese as a growing danger (Skepper, 2011).

Sometimes you need to go into greater depth and refer to some sources in more detail in order to interrogate the methods and stand points expressed by these researchers. Even in this more analytical piece of writing, only the relevant points of the study and the theory are mentioned briefly - but you need a confident and thorough understanding to refer to them so concisely.

For example:

Skepper's recent study introduces a new model for assessing the relative dangers of cheese related-injuries (2011). He identifies the overall total damage done as more important than the frequency of injuries (Skepper, 2011). However, this model does not adequately take into account Archer's theory of 'Under-reporting' which states that people are less likely to report frequently occurring small accidents until a critical mass of injuries are reached (2009).

Further help

See the following study guide for more on this:

Returning to your literature review - link to the discussion

Once you have written your literature review, its job doesn’t end there. The literature review sets up the ideas and concepts that you can draw upon later to help interpret your own findings.

Do your own findings confirm or contradict the previous research? And why might this be?

If your literature review funnels down from broad to narrow, you can think of your discussion like the other half of the hour-glass, broadening out to the wider applications of your project at the end:

Relinking your literature review to your discussion

So although you may draft your literature review as one of your first steps, you will probably come back to it towards the end of your project to redraft it to help fit in with your discussion. You may need to emphasise some studies that didn’t initially seem that important, but which are now more useful because of what you have found in your own experiments.

Example

This is an example of the thinking that might go on behind interpreting a result and linking it to the previous literature:

Finding 95% of the students you surveyed have problems managing their time at university.
What do you think about this? I expected it to be less than that.
What makes you think that? Research I read for my literature survey was putting the figure at 60-70%.
What conclusions can you draw from this? There must be reasons why the figures are so different. The sample I surveyed included a large number of mature students, unlike the samples in the previous research. That was because the brief was to look at time management in a particular department which had a high intake of post-experience students.
Finished paragraph for discussion section The percentage of students surveyed who experienced problems with time management was much higher at 95% than the 60% reported in Jones (2006) or the 70% reported in Smith (2007). This may be due to the large number of mature students recruited to this post-experience course. Taylor (2004) has described the additional time commitments reported by students with young families, and the impact these may have on effective management of study time. The department recognises this, offering flexible seminar times. However it may be that students would benefit from more advice in this area.