Everyone wants good health and healthcare that is effective. But how can we know whether a claimed intervention is truly effective? Many interventions are given with the best of intentions but have later been found to be ineffective with the potential for harm and wasted resource. Where an article is published, or who wrote it should not be an indication of its trustworthiness and relevance.
Critical appraisal skills enable you to systematically assess the trustworthiness, relevance and results of published papers. The Critical Appraisals Skills Programme (CASP) has 25 years of significant and unrivalled expertise in the delivery of training to healthcare professionals. CASP has a series of easy to use checklists to help you read research, and also delivers training through face-to-face workshops, and train the trainer courses.
Using critical appraisal skills and tools enables users of research evidence to reach their own judgements.
CASP approaches research in 3 steps:
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 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.
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.
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.