If you reach the quality assessment step and choose to exclude articles for any reason, update the number of included and excluded studies in your PRISMA flow diagram.
Covidence includes the Cochrane Risk of Bias 2.0 quality assessment template, but you can also create your own custom quality assessment template.
A librarian can advise you on quality assessment for your systematic review, including:
After the screening process is complete, the systematic review team must assess each article for quality and bias. There are various types of bias, some of which are outlined in the table below from the Cochrane Handbook.
The most important thing to remember when choosing a quality assessment tool is to pick one that was created and validated to assess the study design(s) of your included articles.
For example, if one item in the inclusion criteria of your systematic review is to only include randomized controlled trials (RCTs), then you need to pick a quality assessment tool specifically designed for RCTs (for example, the Cochrane Risk of Bias tool)
Once you have gathered your included studies, you will need to appraise the evidence for its relevance, reliability, validity, and applicability.
Quality Assessment tools are questionnaires created to help you assess the quality of a variety of study designs. Depending on the types of studies you are analyzing, the questionnaire will be tailored to ask specific questions about the methodology of the study. There are appraisal tools for most kinds of study designs. You should choose a Quality Assessment tool that matches the types of studies you expect to see in your results. If you have multiple types of study designs, you may wish to use several tools from one organization, such as the CASP or LEGEND tools, as they have a range of assessment tools for many study designs.
Click on a study design below to see some examples of quality assessment tools for that type of study.
Below, you will find a sample of four popular quality assessment tools and some basic information about each. For more quality assessment tools, please view the blue tabs in the boxes above, organized by study design.
|Cochrane Risk of Bias 2.0 Tool||Randomized controlled trials (RCTs)||
The Cochrane Risk of Bias 2.0 tool asks questions about five domains of potential bias for individually randomized trials:
The Newcastle-Ottawa scale assesses the quality of nonrandomized studies based on three broad perspectives:
|CASP Appraisal Checklists||Mixed methods||
These quality assessment checklists ask 11 or 12 questions each to help you identify
Available study designs include randomized controlled trials, systematic reviews, qualitative studies, cohort studies, diagnostic studies, case control studies, economic evaluations, and clinical prediction rules.
|LEGEND Evidence Evaluation Tools||Mixed methods||
These evidence evaluation tools ask questions each to help you examine
across the clinical question domains of intervention, diagnosis & assessment, prognosis, etiology & risk factors, incidence, prevalence, and meaning.
Available study designs include systematic review / meta analysis, meta-synthesis, randomized controlled trials, controlled clinical trials, psychometric studies, cohort-prospective / retrospective, case control, longitudinal, cross sectional, descriptive / epidemiology / case series, qualitative study, quality improvement, mixed methods, decision analysis / economic analysis / computer simulation, case report / n-of-1 study, published expert opinion, bench studies, and guidelines.
Covidence uses Cochrane Risk of Bias (which is designed for rating RCTs and cannot be used for other study types) as the default tool for quality assessment of included studies. You can opt to manually customize the quality assessment template and use a different tool better suited to your review. More information about quality assessment using Covidence, including how to customize the quality assessment template, can be found below. If you decide to customize the quality assessment template, you cannot switch back to using the Cochrane Risk of Bias template.