In this article: What is critical appraisal / How do you critically appraise an article / Quick Links / Statistics / Further Reading

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What is critical appraisal?

Critical appraisal is an essential part of evidence-based practice and involves systematically evaluating evidence to establish whether it is valid, accurate and relevant. It is important to critically evaluate evidence to ensure its quality and clinical relevance for your proposed use. Critical appraisal can also save you time by allowing you to focus on the research that is important to you.

How do you critically appraise an article?

There are some useful tools, checklists and further reading suggestions listed below, which will guide you through the critical appraisal process.

Critical appraisal support and training is provided by our Subject Specialist Librarian Team.  Contact them at: LibrarySubjectTeam@ggc.scot.nhs.uk.

Quick links

The title most often recommended by library staff as an introduction to critical appraisal is:

• Greenhalgh, T. How to read a paper: the basics of evidence based medicine and healthcare. 6th ed. Chichester: John Wiley & Sons; 2019
• Ebook version

As well as being available in print in several editions across the Library Network it is also available to browse online or download to a mobile device as an ebook.  The original BMJ articles from 1997 on which the book chapters are based are also available, see for example:

• Greenhalgh, T. How to read a paper : getting your bearings (deciding what the paper is about), BMJ 1997;315:243

 Alternatively,

• if you don't know how to identify the study type you have in front of you OR
• you already know the study type and want to know what checklists are available

then use the Critical Appraisal Tools pathway to help you select the right tool:

• Critical Appraisal Tools Pathway 

If you do know the checklist you want, here are some of the commonly-used sites: 

• AGREE (Appraisal of Guidelines for Research and Evaluation)
• CASP (Critical Appraisal Skills Programme) Checklists
• CEBMa (Center for Evidence-Based Management) Critical Appraisal Tools
• Centre for Evidence-Based Medicine Critical Appraisal Worksheets
• DISCERN (Genetics and Consumer Health Information)
• Effective Public Health Project Quality Assessment Tool for Quantitative Studies
• GATE: Graphic Appraisal Tool for Epidemiological studies
• Joanna Briggs Institute Critical Appraisal Tools
• National Collaborating Centre for Methods and Tools  (Select 'Search the Registry' link, enter your search term and then limit results to EIPH stage 'Appraise')
• SIGN Critical Appraisal: Notes and Checklists
• Understanding Health Research: a tool for making sense of health studies
• University of Glasgow General Practice and Primary Care EBP Checklists

Statistics

Getting to grips with statistical information is often an area of critical appraisal that people feel daunted by.  General introductory books on critical appraisal will cover the basics, see the reading list below for suggestions, but here are some further resources which focus on this specific topic:

• BMJ Publishing Group : Statistics at Square One
• Health Knowledge : Making Sense of Results
• Khan Academy tutorials on statistics and probability - this resource does not support Internet Explorer browser
• NHS Choices : Health News Glossary
• Understanding Research Evidence by NCCMT
• Students4BestEvidence - A beginner’s guide to interpreting odds ratios, confidence intervals and p-values
  
• Students4BestEvidence - Forest plot at a glance

Further reading

Websites

• Bandolier, What is… Critical Appraisal
• Centre for Evidence-Based Medicine (Oxford)
• Critical Appraisal Tools video (Health Library for North Staffordshire)
• Evidence-Based Medicine (Patient UK)
• Finding and Appraising the Evidence (HealthKnowledge)
• SIGN: Guidelines developer's handbook (includes checklists on methodologies)
• Testing Treatments: key concepts for assessing claims about treatment effects (includes a helpful Critical Appraisal jargon buster)
• Teachers of Evidence Based Healthcare: Learning resources database (includes a wide range of learning resources on finding and appraising evidence)

Books

• Critical appraisal titles from the Knowledge Network