Critical appraisal of journal articles
If you have done a literature search and found some useful looking papers, it's a good idea to assess the quality and validity of the material - particularly if you plan to refer to the results in your own research.
What is critical appraisal?
The concept of critical appraisal has largely grown out of the evidence-based health care movement. It fits into the cycle of getting evidence into practice. This means improving the quality and cost effectiveness of health care by finding the best available research evidence on the outcomes of health care interventions, and basing decisions on health care upon it.
In practice this translates as:
- finding the evidence (searching the most appropriate databases)
- carefully checking the validity of the research (critical appraisal)
- applying the lessons learnt from the evidence to patient care (getting research into practice)
Critical appraisal means being able to look at a piece of research in an objective and structured way to decide how valid it is compared to other research. This page provides you with a number of resources (including appraisal checklists for various study designs) to help you do this.
What relevance does it have to my work?
Critical appraisal is most aptly applied to quantitative studies that look at the effectiveness of different health and medical interventions, eg randomised or blinded controlled trials, crossover trials, meta-analyses or systematic reviews.
Critical appraisal resources
Below is a list of resources which can help you learn for yourself how to critically appraise a journal article, or assist you after you have been taught to do it more formally.
- Evidence-Based Medicine Toolkit: hosted by the University of Alberta, this is an online box of handy tools to help you find, appraise, and apply in practice, evidence-based research
- How to read a paper - a set of guides from the BMJ. General topics include:
- Levels of Evidence: ranking system for various study designs in order of evidence-based merit: systematic reviews/meta-analyses and well conducted randomised controlled trials (RCTs) are usually seen as the best form of evidence, with research based on the outcome of a case series placed somewhere near the bottom
- Netting the Evidence: search for the keyword "appraisal" to find a quality assessed list of appraisal resources
- Teaching materials from the Centre for Evidence Based Medicine (University of Toronto): includes teaching scenarios for use with problem based learning
Critically appraising qualitative research
- How to read a paper: papers that go beyond numbers (qualitative research): more detailed background on appraising qualitative research
Critically appraising quantitative health research
Quality of Life (QOL) measures
- Issues in the measurement of health-related Quality of Life: some tips and background on appraising papers which measure quality of life
Economic evaluations (cost of health care interventions)
- How to read a paper: papers that tell you what things cost (economic analyses): BMJ article explaining how to appraise a paper that evaluates the economic cost of a healthcare intervention
This includes clinical trials, randomised controlled trials, crossover trials, and blinded trial designs.
- How to read a paper: papers that report drug trials: BMJ article explaining how to appraise a report of trial results
Meta-analyses and systematic reviews
- How to read a paper: papers that summarise other papers (systematic reviews and meta-analyses): BMJ article explaining how to appraise a review or meta-analysis
- Systematic Review (of Therapy) Worksheet: produced by the Centre for Evidence Based Medicine at the University of Toronto
Accuracy of diagnostic tests
These include things like the Hospital Anxiety and Depression Scale, or DSM IV.
- Diagnostic Worksheet: produced by the Centre for Evidence Based Medicine at the University of Toronto
- How to read a paper: papers that report diagnostic or screening tests: BMJ article explaining how to appraise a paper about a diagnostic test
- Therapy Worksheet: produced by the Centre for Evidence Based Medicine at the University of Toronto
Prognosis (long term outcome)
- Prognosis Worksheet: produced by the Centre for Evidence Based Medicine at the University of Toronto
Aetiology (risk of harm)
- Harm Worksheet: produced by the Centre for Evidence Based Medicine at the University of Toronto