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Literature reviews - research guide

Critical reading and analysis

Critical reading & analysis

A critical reader:​ ​

  • Does not believe everything they read​ ​
  • Questions what they read​ ​
  • Rereads if necessary​ ​
  • Understands the influence of style​ ​
  • Analyses arguments​ ​
  • Discounts arguments that are unsupported or based on faulty reasoning

When reading critically, focus on the purpose of your literature review:

  • Think about what you expect from the article or chapter, before reading it
  • Skim the abstract, headings, conclusion, and the first sentence of each paragraph
  • Focus on the arguments presented rather than facts
  • Take notes as you read and start to organise your review around themes and ideas
  • Consider using a table, matrix or concept map to identify how the different sources relate to each other
  • Note four to six points for each study that summarises the main points and conclusions
  • Be as objective as possible

Critical appraisal

Critical appraisal is the process of carefully and systematically examining research to judge its credibility, its value and its relevance in a specific context.

The aim of critical appraisal is to understand the strengths, weaknesses, and potential for bias in the research. Validity, applicability, and clinical importance should be considered during critical appraisal to ensure that research evidence is used reliably and efficiently and false conclusions are not drawn.

Why do we need to critically appraise the literature?

Critical appraisal is necessary to:

  • Assess benefits and strengths for research against flaws and weaknesses
  • Decide whether studies have been undertaken in a way that makes their findings reliable
  • Make sense of the result
  • Know what these results mean in the context of the clinical decision being made
  • Assess the usefulness of  the evidence for clinical decisions

Elements of sources

  • Abstract: this is what the author wants the reader to take away from their article - what is the starting point? ​ ​
  • Introduction: provides background and a starting point - how does it guide the reader?​ ​
  • Materials and methods: often overlooked but very important - is the methodology understandable, reproducible, direct and robust?
  • Results: summary and analysis of the data but the statistical reporting is just as important as the words ​ ​
    • What do the tables, figures and legends actually report? ​ ​
    • What do you think the data means? Decide before reading the discussion​.
  • Discussion: author draws conclusions – how does this correlate with your conclusions?

Evaluation of sources

Consider the following criteria:

Currency

  • Is the source up-to-date?​
  • Does it consider the latest research on your topic?​

Relevance

  • Is the article relevant to your topic?​
  • Is the research methodology comprehensively described?​
  • Does the work ultimately contribute in any significant way to an understanding of the subject?

Authority

  • How reputable is the source?​
  • Is the source peer-reviewed?​
  • What is the source's impact factor?
  • Is the author from a reputable institution?​
  • Have you seen the author cited in other sources?​

Accuracy

  • Does the data support the conclusions drawn?​
  • Are the author's opinions and conclusions convincing? 
  • Are the author's arguments supported by evidence (primary material, case studies, narratives, statistics, recent findings)?​ ​
  • Is the article properly referenced?​

Bias

  • What is the purpose of the article and its intended audience?​
  • Can you detect any bias in the content?​
  • Is the reporting objective?​
  • Is contrary data considered or is certain pertinent information ignored to prove the author's point?
  • Which of the author's arguments are most/least convincing?​ ​

Inference

  • Were the objectives achieved? ​ ​
  • Hypotheses tested? ​ ​
  • How do these results relate to other studies you have found?​ ​
  • Do the authors openly discuss any limitations of their study?​ ​
  • What else needs be studied in the future?

Interpretation

  • Read critically​ ​
  • Note 2-4 bullet points for each study that summarises the main points and conclusions​ ​
  • Use matrix to analyse findings, relevance and importance of each text​ ​
  • Draw attention to studies that are important, influential or that bring a new understanding or method of studying your area of research

Tools

Author analysis

Databases such as Scopus and Web of Science can be used to:

  • Locate the papers of a specific author
  • Compare the research output of more than one author

The h-index

The h-index is a metric that allows you to compare the publications or research output of authors. This metric is calculated by determining the number of articles (n) written by an author, in the database, that have received the same number or more (n) citations over time. The h-index is a useful metric for comparing rates of publication, as the value is not skewed by a single highly cited paper, nor by a large number of poorly cited papers.

Note:

  • The h-index is not a static value – if discussing an author’s h-index, you need to specify the date on which the h-index was calculated.
  • The h-index is also calculated by other databases/resources and may vary from the h-index given by Scopus – if discussing an author’s h-index, you need to specify the source of the h-index.

See the example below of how an author's h-index may appear in Scopus.

Line chart showing an author's h-index based upon the number of documents and number of citations to the author's name.

Scopus

To locate papers of an author in Scopus:

  1. Go to the default Scopus search screen and select Authors tab.
  2. Enter the author details and affiliation (university). Only include author surname for a comprehensive search. If the author has a common surname, include the first name's initial only.
  3. The author’s details and the documents that they have written, and which are indexed by Scopus, will be retrieved. Click on the author’s name to see a full list of their publications.

The information about the author will also tell you:

  • How many of their publications have been indexed by Scopus
  • How many times their publications have been cited
  • Which of their publications are most highly cited
  • Who they have co-authored papers with
  • Their publication and citation trends for the past nine years
  • Their h-index

See the Scopus resources below for more help:

Web of Science Core Collection

To locate papers of an author in Web of Science Core Collection (WoS CC):

  1. Go to the default WoS CC search screen and select Researchers tab.
  2. Enter the author's surname and first name's initial.

  3. The author’s details and the papers that they have written, and which are indexed by WoS CC, will be retrieved. Click on the Publications tab to see a full list of their publications.

The information about the author will also tell you:

  • How many of their publications have been indexed by WoS CC
  • How many times their publications have been cited
  • Which of their publications are most highly cited
  • Their h-index

The author's citation report will tell you:

  • How many of their publications have been indexed by WoS CC
  • How many times their publications have been cited
  • Which of their publications are most highly cited
  • Their h-index

The Measuring research quality and impact guide has more detailed information on author analytics:

Source/journal analysis

Databases such as Scopus and Web of Science (including CAB Abstracts) can be used to determine the quality of journals in a discipline or field of research. For more information on journal analytics, please see the relevant section of our guide on Measuring Research Quality & Impact:

Taking clear, legible notes will help to focus your critical reading and analysis of your literature review sources. When taking notes, avoid plagiarism by:

  •  Keeping track of the difference between information from your sources and from your own ideas
  •  Providing clear references, including page numbers

Note taking methods

Some effective methods of note-taking include:

  • Outlining method. Use headings, sub-headings and bullet points to organize topics
  • Cornell method. Use two columns - in one column write your summary of the authors' conclusions and evidence, and in the other column write down your own analysis and other comments
  • Charting method. Create a list of topics or points you want to write about - use a column for each one. As you read, add references and make notes in the appropriate column
  • Sentence method. Simply write down new ideas and bits of information as a numbered  sentence
  • Mapping method. Write down key concepts and terms, with related ideas radiating out from these

You may consider using the matrix below for your note taking and analysis:

Critical reading & analysis checklist

  1. Does your literature review highlight flaws, gaps, or shortcomings of specific texts or groups of texts?
  2. Have you identified areas that have not yet been researched or have not yet been researched sufficiently?
  3. Does the literature demonstrate a change over time or recent developments that make your research relevant now?
  4. Are you able to discuss research methods used to study this topic and/or related topics?
  5. Can you clearly state why your research is necessary?
Subjects: Research