Scales blog

What is critical appraisal?

In a world of information overload, trying to keep up to date and implement evidence based practice (EBP) is a challenge.  Critical appraisal is one aspect of the EBP cycle that supports decision making.  It is a logical process to help weigh up the benefits and strengths of research against its flaws and weaknesses.  This evidence can then be used in supporting health care decision making.

 The Critical Appraisal Skills Programme (CASP) approaches reviewing research in 3 steps:

 1. Is the study valid?

The first step is to decide whether the study was unbiased by evaluating its methodological quality.

 2. What are the results?

If we decide that the study is valid, we can go on to look at the results. At this step we consider whether the study’s results are clinically important. For example, did the experimental group show a significantly better outcome compared with the control group? We also consider how much uncertainty there is about the results, as expressed in the form of p values, confidence intervals and sensitivity analysis.

 3. Are the results useful?

Once you have decided that your evidence is valid and important, you need to think about how it applies to your question. It is likely, for example, that your patient or population may have different characteristics to those in the study.

 Critical appraisal skills provide a framework within which to consider these issues in an explicit, transparent way.

 Who is it for?

It is for anyone that wants to use research evidence in their professional practice, professional and personal decision making, and policy & guidelines development.

 Where can I find out more about it?

To help you learn the skills to read a research paper we run training sessions for beginners which will equip you with the skills to critically appraise a research paper using an approved checklist or decide if a paper is worth reading and assess its strengths and weaknesses. (See our flyer here for dates)

 Here’s an example in practice:

Your clinical department wants to improve the organisation of the outpatient clinic, and you have found a systematic review of relevance and a recent patient survey report. The clinical management team meet in 3 weeks to discuss potential changes. Two members of the group critically appraise the review and read the survey report independently, and discuss their findings ahead of the meeting. At the beginning of the team meeting they report back on the review and its findings, these underpin the next stage of discussion about reconfiguring the clinic that includes the results of a patient survey and the views & experiences of the management team.

Other useful sources:


Behind the headlines

Cochrane Library

How to read a paper




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