Critical appraisal

What is critical appraisal?

'Critical appraisal is the process of carefully and systematically examining research to judge its trustworthiness, and its value and relevance in a particular context.' ⁽¹⁾

It is a systematic framework to assist you to interpret the quality and relevance of research.

Why should I do critical appraisal?

The amount of published information is growing rapidly and many clinical practitioners have reached the point of information overload. How do you decide which is worth reading and which is worth acting upon?

Critical appraisal asks ⁽²⁾

• Is the study question relevant?
• Does the study add anything new?
• What type of research question is being asked?
• Was the study design appropriate for the research question?
• Did the study methods address the most important potential sources of bias?
• Was the study performed according to the original protocol?
• Does the study test a stated hypothesis?
• Were the statistical analyses performed correctly?
• Do the data justify the conclusions?
• Are there any conflicts of interest?

Research may be undertaken to answer a wide range of questions and there are a myriad of ways to conduct research.

It is important that the methodology chosen is appropriate to the question and that the methodology has been appropriately applied.

Ideally the research has no bias in the methodology that may skew the results. If there is a perceived bias, have the researchers done all that they can to minimise the impact of that bias?

What are the results?

How was the data collected and was the data analysis appropriate? The author should clearly state how the data was collected and analysed. Are the results statistically significant or might they have occurred by chance?

How can this knowledge assist me in clinical practice?

Ask yourself:

• were the results found amongst a population similar to one of my patient group?
• are there any significant differences and how might they be handled?
• were there any adverse effects that should be considered?
• do I have the professional competences to undertake these changes to my practice?

Learn more about critical appraisal

There are number of tools to help you undertake critical appraisal. The most used is the Critical Appraisal Skills Programme (CASP). This website contains a great deal of useful information about the CASP approach including checklists and details of workshops.

These tools and checklists are specific to study design:

• Critical appraisal tools at the University of Oxford Centre for Evidence-Based Medicine
• SIGN critical appraisal checklists
• JBI Critical appraisal tools
• AMSTAR checklist (for the Quality Assessment of Systematic Reviews)
• BMJ Best Practice: Practical EBM tools

Critical appraisal for antiracism

To address issues such as minoritised ethnic groups’ under-representation, and the effect of racial bias on medical research and its application, a short checklist of five questions is provided to be used alongside existing tools: Critically Appraising for Antiracism

Guide to critical appraisal 

This guide covers bias in studies, study design, RCTs, systematic reviews, and key questions to consider when critically appraising a paper:

References

1. Burls A. What is critical appraisal? Newmarket: Hayward Medical Communications; 2009.
2. Young J M, Solomon M J. How to critically appraise an article. Nat Clin Pract Gastroenterol Hepatol. 2009;6(2):82-9.