Background to Critically Appraised Evidence
Critical appraisal is a process within the evidence-based medicine model that involves a systematic evaluation of research to determine its quality. The critical appraisal of evidence gives readers the opportunity to identify the risk of bias in a selected study and apply a systematic analysis to ensure that biases have not influenced the research results in any meaningful way.
Critical appraisal also provides readers with the opportunity to evaluate results of a study for their applicability in other, and potentially more relevant, settings.
Tools for Reviewers
- CASP (Critical Appraisal Skills Programme) - Tools and checklists for the critical appraisal of systematic reviews, randomized controlled trials, diagnostic test studies, economic evaluation studies, qualitative research, case control studies, and cohort studies.
- Centre for Evidence-Based Medicine (Toronto) - Critical appraisal worksheets for systematic reviews as well as diagnosis, harm, prognosis, and therapy studies.
- Centre for Evidence-Based Medicine (UK) - Critical appraisal worksheets for systematic reviews, diagnosis studies, prognosis research, and therapy or randomized controlled trial studies.
- Cochrane Handbook for Systematic Reviews of Interventions - A guide to conducting Cochrane systematic reviews. See Chapter 8: Assessing risk of bias in included studies.
- GRADE (Grading of Recommendations Assessment, Development and Evaluation) Working Group - Resources, including guidelines, to grade the quality of medical evidence and assign a level of recommendation. Produced by the Grading of Recommendations Assessment, Development and Evaluation Working Group.
- Jadad Scale - Simple, yet widely used quality assessment questionnaire for randomized controlled trials.
- Joanna Briggs Institute Critical Appraisal Tools - Checklists for reviewing randomized controlled trials, systematic reviews, case control, case reports, diagnostic test accuracy, qualitative, and many more study types.
- NOS (The Newcastle-Ottawa Scale) - A quality assessment tool for assessing nonrandomized studies.
- PEDro Scale - A checklist that rates the quality and interpretability of clinical trials.
- 'Risk of bias' assessment tool for non-randomised studies for interventions - A Cochrane risk of bias assessment tool (ACROBAT-NRSI) developed through collaborative research between the Bias Methods Group and the Non-Randomised Studies Group.
Instruments and Reporting Guidelines for Authors
Randomized Controlled Trials
CONSORT (Consolidated Standards of Reporting Trials) - Guidelines for the reporting of randomized controlled trials.
SPIRIT Statement - Recommendation for reporting clinical trials.
TiDieR (Template for Intervention Description and replication) - Checklist and guide for reporting interventions.
MOOSE (Meta-analysis of Observational Studies in Epidemiology) - Guidelines for reporting meta-analyses of observational studies in epidemiology. PMID: 10789670.
STROBE (STrengthening the Reporting of Observational Studies in Epidemiology) - Guidelines for reporting various types of observational (cohort, case-control, and cross-sectional) studies in epidemiology.
- TREND Statement (Transparent Reporting of Evaluations with Nonrandomized Designs) - This set of guidelines from the CDC contains items for reporting nonrandomized control trials.
PRISMA Statement (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) - Formerly QUOROM, PRISMA offers guidelines for the reporting of systematic reviews and meta-analyses.
Cochrane Risk of Bias Tool - The Cochrane Collaboration’s domain-based evaluation tool for assessing the methodological quality of systematic reviews.
Quality Improvement Studies
SQUIRE Guidelines (Standards for QUality Improvement Reporting Excellence) - Guidelines for quality improvement reporting.
CARE (CAse REports) Statement - Guidelines for the reporting of case reports.
STARD (Standards for Reporting Diagnostic Accuracy) - Checklist for reporting the quality of diagnostic accuracy studies.
SRQR (Standards for Reporting Qualitative Research) - Recommends a list of 21 items for reporting qualitative research.
COREQ (Consolidated Criteria for Reporting Qualitative Research) - Offers a 32-item checklist for interviews and focus groups.
Find more reporting guidelines
EQUATOR network - Access to over 300 reporting guidelines.
- SIGN Critical Appraisal: Notes and Checklist - Appraisal tools for systematic reviews and meta-analyses, randomized controlled trials, as well as cohort, case-control, diagnostic, and economic studies from the Scottish Intercollegiate Guidelines Network.
Critically Appraised Summary Resources
The following links connect you to critical appraisal tools for resources that summarize multiple studies.
Clinical Practice Guidelines Appraisal Tool
AGREE II Instrument - The Appraisal of Guidelines for Research and Evaluation (AGREE) Instrument addresses the quality of practice guidelines.
Additional Tools for Synthesized Reports
- the NNT - Brief summaries of NNT “Number-Needed-to-Treat” based on critical appraisal of systematic reviews related to therapy or diagnosis studies.
- ACP Journal Club - Summaries of evidence from over 130 clinical journals. Published by the American College of Physicians-American Society of Internal Medicine.
- EvidenceUpdates - Access to articles from over 110 clinical journals that have been critically appraised by a panel of practicing physicians. Includes a searchable database and email alerts option. From BMJ Publishing Group and McMaster University's Health Information Research Unit.
Find it at Galter
- Basic statistics and epidemiology : a practical guide / Anthony Stewart.
- Biostatistics and Epidemiology : A Primer for Health and Biomedical Professionals / by Sylvia Wassertheil-Smoller, Jordan Smoller.
- Interpreting statistical findings : a guide for health professionals and students / Jan Walker and Palo Almond.
- Quantitative methods for health research : a practical interactive guide to epidemiology and statistics / Nigel Bruce, Daniel Pope and Debbi Stanistreet.
- Statistical methods in epidemiologic research / Ray M. Merrill.
- Statistics in medicine / R. H. Riffenburgh.
- Studying a study and testing a test : how to read the medical evidence / Richard K. Riegelman.
- Evidence-Based Practice: Appraise - Appraisal tools provided by Duke University Medical Center Library and Archives.
- Critical Appraisal Tools - Links to critically appraisal tools provided by the University of South Australia.
- Users' Guides to the Medical Literature - Detailed information about medical literature in evidence-based medicine. Provided by JAMAevidence.
- Oxford Centre for Evidence-based Medicine Levels of Evidence - Grades the strength of evidence.
- Irwig L et al. Smart Health Choices: Making Sense of Health Advice. Chapter 18, Relative risk, relative and absolute risk reduction, number needed to treat and confidence intervals. London: Hammersmith Press; 2008.
- Andrade, C. . The numbers needed to treat and harm (NNT, NNH) statistics: what they tell us and what they do not. The Journal of clinical psychiatry, 76(3), 330-333; 2015.
Updated: December 11th, 2017 11:17