NUTR 6200: Research in Clinical Nutrition: Literature Reviews

You will first want to determine a topic for your review.  If you are working on an assignment, this may be provided for you or determined by the field you are studying.  Your topic may also be inspired by a friend, family member,  patient, or client you have worked with, an area you are interested in, or an area where you have seen conflicting data, results, or recommendations.  Run a simple search to see if the topic has been thoroughly explored.

Next, identify your question.  Mind mapping or brainstorming may be helpful.  It is helpful to write the question as a question rather than a statement.  Your question should also be neutral rather than biased in one direction or another.    Finally, your question should be answerable within the timeframe you have for your project and with the resources you have available to you.

Once you begin searching, you may decide your question is too broad or too narrow.  It is okay to refine your question after you have started investigating the literature.

In this step, you will find materials relevant to the subject you are exploring.  Keep in mind, not all databases are created equally.  They may have different focuses and include different types of materials.  A librarian may be very helpful in determining which databases will be most helpful for your query and in creating an effective search for the database you are searching.  The librarian can also help you determine effective keywords for your search.

When searching, be sure to utilize synonyms and alternative terms in your search.  You may miss pertinent resources if you do not use alternative terms.  Instead of searching for "child", you could search for "child AND children AND kid AND kids AND pediatric AND pediatrics AND paediatric AND paediatrics AND adolescent AND adolescents"...  You will have far more results when you combine search terms instead of searching for a single term.

Be sure you understand how to properly combine search terms.  For more information about combining search terms and other search techniques, check out the site below:

A Literature Matrix may assist you in this step!

Next, you will want to evaluate the data you have found to determine which literature makes a significant contribution to your understanding of the topic you are searching.

Read through the articles you have selected to include in your literature review.  Take notes, in your own words, of the pertinent details, being sure that you know which details came from which sources.

• Choose what format you will use to take notes
• Define key terms in the literature
• Note key statistics
• Select useful quotes
  • Don't use too many
  • Do not copy direct quotes without attributing them to the original author
  • Note the source including page number for easy citation later
• Note the different emphasis, strengths, and weaknesses of each study
• Identify major trends and patterns in the literature
• Identify gaps in the literature
• Identify relationships in the literature
  • Note if one study is based on or follows another

From:  Mongan-Rallis H. Guidelines for writing a literature review. URL https://www.duluth.umn.edu/~hrallis/guides/researching/litreview.html. Updated April 19, 2018. Accessed January 11, 2019.

When reading through, be sure to think about the following:

• Author
  • Are the author's credentials well-respected?
  • Are the author's affiliations also well-respected?
    • Could the author's affiliations introduce bias?
• Arguments
  • Are the author's theories supported by sound evidence/research?
• Objectivity
  • Does the tone of the study seem biased?
• Persuasiveness
  • Which theories are most/least convincing?
• Value
  • Does the work contribute to your understanding of the topic?

This is the step where you put it all together.  You will discuss the findings and conclusions of the pertinent literature.

Even if your literature review is not a stand-alone paper, it should include the following structure, to establish a logical flow for your reader:

Introduction

• Identify your topic, issue, or area of concern and why it is important - give a context
  • Avoid blanket or global statements
• Point out trends in what has been published about the topic, conflicts in the literature, gaps in the research, or an area of interest
• Explain your reasoning (point of view) for the review, explain the criteria or sequence for your literature comparisons, and explain why you left out certain key pieces of literature within the topic area
• Note specifically what you will cover in this review and what you will not cover

Body

• Group the articles
  • type of literature (case studies, theoretical articles, reviews, etc.) and by common types (qualitative or quantitative)
    • "Case studies in this field have shown..."
    • "Randomized controlled trials by... have shown that..."
    • "Cohort studies from China show that...however, cohort studies from the United States indicate..." 
  • by the author's conclusions
    • "Studies conducted by...found that..."
    • "In contrast, studies conducted by...found..."
    • "One reason these studies contradict each other could be..."
  • by the purpose or objective of the article
    • "The authors of three randomized controlled trials and two cohort studies found..."
    • "Several scholars supported the idea that..."
  • chronology - if studies are landmark studies, identify them as such
    • "Early studies in the field found that..."
    • "However, studies conducted in the last five years found..."
    • "In his landmark study from 1975, Smith discovered...Jones replicated Smith's study in 2018 and found..."
  • etc.  
• Summarize the main points from the group of articles
• Summarize studies based on their importance within the review - space denotes significance
• Use appropriate transitions and brief "so what" summaries at the ends of groupings to aid in understanding and flow

Conclusion

• Summarize major contributions
• Continue the focus you had in the introduction
• Evaluate the most recent developments in the field
• Point out gaps in the literature, inconsistencies, and areas for future study
• Provide insight into the importance of the topic within the broader field of study or the profession
• If the lit review is a stand-alone paper, re-state your thesis and note how you have supported that statement with the chosen literature
• If the lit review is part of a larger research paper, lead the reader into the questions that will be addressed by your research