We critically appraise the literature in order to:
Not all studies are trustworthy. In order for your systematic review to represent the best possible evidence, the research team must critically appraise each study thoroughly before it is included. The criteria by which you assess included studies should be clearly outlined in your report/protocol. You should also maintain a record of which studies have been left out, and the grounds for which they were excluded.
A number of tools and checklists have been devised for assessing the quality of both quantitative and qualitative studies. Following is a selection of useful resources.
Critical appraisal tools:
Critical appraisal worksheets to help you appraise the reliability, importance, and applicability of clinical evidence.
CASP (International) grew out of the work of the Critical Appraisal Skills Programme in Oxford, (known as CASP UK within the network), this work began in 1993 to help health care decisions makers understand scientific evidence.