The Critical Appraisal Skills Programme (CASP) is part of Better Value Healthcare, and based in Oxford. The programme has been running since 1993 and has developed tested workshops and tools for critically appraising a wide range of research.

CASP workshops and resources help participants learn how to systematically formulate questions, find research evidence, appraise research evidence, and act on what they find.

The philosophy of CASP has always been about sharing knowledge and understanding, working in ways that are non-hierarchical, multidisciplinary and using problem-based approaches. This ensures that it is accessible and has practical day-to-day application.


Who is CASP for? CASP is for anyone who wants to use research evidence in their professional practice, professional and personal decision making, and policy & guidelines development.

Why appraise the evidence?Where an article is published, or who the author is, should not be an indication of its trustworthiness and relevance. Using critical appraisal skills and tools enables users of research evidence to make their own judgements.

CASP approaches 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. Different criteria for validity of articles are used for different types of question: questions on treatment, diagnosis, prognosis and economic evaluation. Depending on the validity of an article we can classify it within a scale of levels of evidence and degrees of recommendation.

2. What are the results? If we decide that the study is valid, we can go on to looking 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 and confidence intervals.

3. Are the results useful? Once you have decided that the study is valid and important, you need to think about how it applies to your question, and context for decision making. It’s likely, for example, that your patients or population of interest may have different characteristics to those in the study. Critical appraisal provides a framework within which to consider these issues in an explicit, transparent way.

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CASP has 8 critical appraisal tools, designed to be used when reading research. These include (click to download):

The tools are free to download and are also available on the CASP website and can be used by anyone under the Creative Commons License.