Once screening (article selection) is completed, the Quality Assessment part of the systematic review process may begin. Quality assessment may be performed before or after data extraction.
Since systematic reviews rely on data from other studies, the evidence in a systematic review is only as good as, or as free from bias as, the included studies. Therefore, the methodological quality of each individual study included in a systematic review should be assessed. This process involves appraising, judging, and documenting potential risks of bias.
We recommend that you use Covidence to conduct quality assessment.
Critical appraisal of scientific studies is important because it helps assess the trustworthiness, relevance, and quality of research, allowing researchers and practitioners to make informed decisions based on reliable evidence. It also aids in distinguishing between strong and weak studies, reducing information overload and bias in clinical practice. Each study should be appraised using a critical appraisal tool specific to each study design. For help in deciding which risk of bias / quality assessment tool(s) to use for each study design, consult one of the following sites.