Critical appraisal can be defined as "the process of carefully and systematically examining research to judge its trustworthiness, and its value and relevance in a particular context" (Burls 2009 p. 1).
Why Critically Appraise Literature?
Critical appraisal skills are often discussed in the context of evidence-based practice in the fields of nursing, midwifery, health sciences, pharmacy and medicine. This involves finding and critically appraising relevant research for its validity, relevance and reliability before it is combined with the expertise of the health practitioner (and the patients preferences) in treating patients.
This systematic approach can be applied in assessing the quality of research studies in other fields.
It is often assumed that if an article is published in a journal it must be of quality; this is not always the case.
It has been argued that most, "if not in fact 99%, of published articles belong in the bin, and should certainly not be used to inform practice" (Greenhalgh 2014 p. 28). They may use "inappropriate designs, unrepresentative samples, small samples, incorrect methods of analysis, and faulty interpretation" (Altman 1994 p. 283).
When reading journal articles and studies it is important to ask yourself if the research is methodologically sound, relevant, is of value to the subject area and patients, has minimized the effects of potential biases and is reported in a clear way.
What was the research question and why was the study needed?
What was the research design?
Was the design appropriate to the question?
Did the study meet expected standards of ethics and governance?
If you are an undergraduate student you will probably find these resources sufficient to allow you to successfully complete your critical appraisal assignment.
Postgraduate research students and staff working at a higher level may also wish to consult our additional resources page for further materials.
There is considerable overlap in the checklists for the same types of research from different organisations. The CASP checklists are possibly the most widely used but you may find you prefer the style of one organisation's lists to another. If in doubt you may wish to consult your lecturer.
The following may facilitate the appraisal of more complicated studies and assist postgraduate research students and members of staff working in greater depth and/or seeking to critically appraise studies for possible inclusion or exclusion from systematic reviews.