Grades and Levels of Evidence: Difference between revisions
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[http://www.cebm.net/index.aspx?o=4590 Download a pdf of this chart here.] | [http://www.cebm.net/index.aspx?o=4590 Download a pdf of this chart here.] | ||
== Grades of Evidence<ref>Guyatt GH, Sackett DL, Sinclair JC, et al. Users' guides to the medical literature. IX. A method for grading health care recommendations. Evidence-Based Medicine Working Group. JAMA. 1995;274(22):1800-1804.</ref> == | == Grades of Evidence<ref>Guyatt GH, Sackett DL, Sinclair JC, et al. Users' guides to the medical literature. IX. A method for grading health care recommendations. Evidence-Based Medicine Working Group. JAMA. 1995;274(22):1800-1804.</ref> == | ||
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|- | |- | ||
| colspan="2" | '''Grades of Recommendation''' | | colspan="2" | '''Grades of Recommendation''' | ||
| '''Strength of Evidence''' | | '''Strength of Evidence''' | ||
|- | |- | ||
| '''A ''' | | '''A ''' | ||
| Strong Evidence | | Strong Evidence | ||
| A prepoderance of level I and/or level II studies support the recommendation. This must include at least 1 level I study. | | A prepoderance of level I and/or level II studies support the recommendation. This must include at least 1 level I study. | ||
|- | |- | ||
| '''B''' | | '''B''' | ||
| Moderate Evidence | | Moderate Evidence | ||
| A single high-quality randomized controlled trial or a preponderance of level II studies support the recommendation | | A single high-quality randomized controlled trial or a preponderance of level II studies support the recommendation | ||
|- | |- | ||
| '''C''' | | '''C''' | ||
| Weak Evidence | | Weak Evidence | ||
| A single level II study or a preponderance of level III and IV studies including statements of consensus by content experts support the recommendation | | A single level II study or a preponderance of level III and IV studies including statements of consensus by content experts support the recommendation | ||
|- | |- | ||
| '''D''' | | '''D''' | ||
| Conflicting Evidence | | Conflicting Evidence | ||
| Higher-quality studies conducted on this topic disagree with respect to thier conclusions. The recommendation is based on these conflicting studies | | Higher-quality studies conducted on this topic disagree with respect to thier conclusions. The recommendation is based on these conflicting studies | ||
|- | |- | ||
| '''E''' | | '''E''' | ||
| Theoretical/ Foundational Evidence | | Theoretical/ Foundational Evidence | ||
| A preponderance of evidence from animal or cadaver studies, from conceptual models/principles, or from basic sciences/bench research support this conclusion | | A preponderance of evidence from animal or cadaver studies, from conceptual models/principles, or from basic sciences/bench research support this conclusion | ||
|- | |- | ||
| '''F''' | | '''F''' | ||
| Expert Opinion | | Expert Opinion | ||
| Best practice based on the clinical experience of the guidelines development team | | Best practice based on the clinical experience of the guidelines development team | ||
|} | |} | ||
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== Recent Related Research (from [http://www.ncbi.nlm.nih.gov/pubmed/ Pubmed]) == | |||
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== References == | == References == | ||
Revision as of 17:51, 8 June 2009
Original Editor - Tyler Shultz
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Discussion & Background[edit | edit source]
Levels of Evidence[1]
[edit | edit source]
Level |
Therapy/Prevetion, Aetiology/Harm |
Prognosis |
Diagnosis |
Differential Diagnosis |
Economic and Descision Analysis |
1A |
SR (with homogeneity) of RCTs |
SR (with homogeneity) of inception cohort studies; CDR validated in different populations |
SR (with homogeneity) of Level 1 diagnostic studies; CDR with 1b studies from different clinical centres |
SR (with homogeneity) of prospective cohort studies |
SR (with homogeneity) of Level 1 economic studies |
1B |
Individual RCT (with narrow Confidence Interval) |
Individual inception cohort study with > 80% follow-up; CDR validated in a single population |
Validating cohort study with good reference standards; or CDR tested within one clinical centre |
Prospective cohort study with good follow-up |
Analysis based on clinically sensible costs or alternatives; systematic review(s) of the evidence; and including multi-way sensitivity analyses |
1C |
All or none series |
All or none case serires |
Absoulute SpPins and SnNouts |
All or none case series |
Absolute better-value or worse-value analyses |
2A |
SR (with homogeneity) of cohort studies |
SR (with homogeneity) of either retrospective cohort studies or untreated control groups in RCTs |
SR (with homogeneity) of Level >2 diagnostic studies |
SR (with homogeneity) of 2b and better studies |
SR (with homogeneity) of Level >2 economic studies |
2B |
Individual cohort study (including low quality RCT; e.g., <80% follow-up) |
Retrospective cohort study or follow-up of untreated control patients in an RCT; Derivation of CDR or validated on split-sample only |
Exploratory cohort study with good reference standards; CDR after derivation, or validated only on split-sample or databases |
Retrospective cohort study, or poor follow-up |
Analysis based on clinically sensible costs or alternatives; limited review(s) of the evidence, or single studies; and including multi-way sensitivity analyses |
2C |
"Outcomes" Research; Ecological studies |
"Outcomes" Research |
Etiological Studies |
Audit or outcomes research | |
3A |
SR (with homogeneity) of case-control studies |
SR (with homogeneity) of 3b and better studies |
SR (with homogeneity) of 3b and better studies |
SR (with homogeneity) of 3b and better studies | |
3B |
Individual Case-Control Study |
Non-consecutive study; or without consistently applied reference standards |
Non-consecutive cohort study, or very limited population |
Analysis based on limited alternatives or costs, poor quality estimates of data, but including sensitivity analyses incorporating clinically sensible variations. | |
4 |
Case-series (and poor quality cohort and case-control studies) |
Case-series (and poor quality prognostic cohort studies) |
Case-control study, poor or non-independent reference standard |
Case-series or superseded reference standards |
Analysis with no sensitivity analysis |
5 |
Expert opinion without explicit critical appraisal, or based on physiology, bench research or "first principles" |
Expert opinion without explicit critical appraisal, or based on physiology, bench research or "first principles" |
Expert opinion without explicit critical appraisal, or based on physiology, bench research or "first principles" |
Expert opinion without explicit critical appraisal, or based on physiology, bench research or "first principles" |
Expert opinion without explicit critical appraisal, or based on physiology, bench research or "first principles" |
Produced by Bob Phillips, Chris Ball, Dave Sackett, Doug Badenoch, Sharon Straus, Brian Haynes, Martin Dawes since November 1998. Updated by Jeremy Howick March 2009.
Download a pdf of this chart here.
Grades of Evidence[2][edit | edit source]
Grades of Recommendation | Strength of Evidence | |
A | Strong Evidence | A prepoderance of level I and/or level II studies support the recommendation. This must include at least 1 level I study. |
B | Moderate Evidence | A single high-quality randomized controlled trial or a preponderance of level II studies support the recommendation |
C | Weak Evidence | A single level II study or a preponderance of level III and IV studies including statements of consensus by content experts support the recommendation |
D | Conflicting Evidence | Higher-quality studies conducted on this topic disagree with respect to thier conclusions. The recommendation is based on these conflicting studies |
E | Theoretical/ Foundational Evidence | A preponderance of evidence from animal or cadaver studies, from conceptual models/principles, or from basic sciences/bench research support this conclusion |
F | Expert Opinion | Best practice based on the clinical experience of the guidelines development team |
Recent Related Research (from Pubmed)[edit | edit source]
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References[edit | edit source]
- ↑ Levels of Evidence. 2009. Available at: http://www.cebm.net/index.aspx?o=1025 [Accessed June 8, 2009].
- ↑ Guyatt GH, Sackett DL, Sinclair JC, et al. Users' guides to the medical literature. IX. A method for grading health care recommendations. Evidence-Based Medicine Working Group. JAMA. 1995;274(22):1800-1804.