Levels of Evidence
1a:
|
Systematic
reviews (with homogeneity) of randomized controlled trials
|
1b:
|
Individual
randomized controlled trials (with narrow confidence interval)
|
1c:
|
All or
none randomized controlled trials
|
2a:
|
Systematic
reviews (with homogeneity) of cohort studies
|
2b:
|
Individual
cohort study or low quality randomized controlled trials (e.g. <80 follow-up="" span="">80>
|
2c:
|
"Outcomes"
Research; ecological studies
|
3a:
|
Systematic
review (with homogeneity) of case-control studies
|
3b:
|
Individual
case-control study
|
4:
|
Case-series
(and poor quality cohort and case-control studies)
|
5:
|
Expert
opinion without explicit critical appraisal, or based on physiology, bench
research or "first principles"
|
1a:
|
Systematic
review (with homogeneity) of Level 1 diagnostic studies; or a clinical
decision rule with 1b studies from different clinical centers.
|
1b:
|
Validating
cohort study with good reference standards; or clinical decision rule tested
within one clinical center
|
1c:
|
Absolute
SpPins And SnNouts (An Absolute SpPin is a diagnostic finding whose
Specificity is so high that a Positive result rules-in the diagnosis. An Absolute
SnNout is a diagnostic finding whose Sensitivity is so high that a Negative
result rules-out the diagnosis).
|
2a:
|
Systematic
review (with homogeneity) of Level >2 diagnostic studies
|
2b:
|
Exploratory
cohort study with good reference standards; clinical decision rule after
derivation, or validated only on split-sample or databases
|
3a:
|
Systematic
review (with homogeneity) of 3b and better studies
|
3b:
|
Non-consecutive
study; or without consistently applied reference standards
|
4:
|
Case-control
study, poor or non-independent reference standard
|
5:
|
Expert
opinion without explicit critical appraisal, or based on physiology, bench
research or "first principles"
|
1a:
|
Systematic
review (with homogeneity) of inception cohort studies; or a clinical decision
rule validated in different populations.
|
1b:
|
Individual
inception cohort study with > 80% follow-up; or a clinical decision rule
validated on a single population
|
1c:
|
All or
none case-series
|
2a:
|
Systematic
review (with homogeneity) of either retrospective cohort studies or untreated
control groups in randomized controlled trials.
|
2b:
|
Retrospective
cohort study or follow-up of untreated control patients in a randomized
controlled trial; or derivation of a clinical decision rule or validated on
split-sample only
|
2c:
|
"Outcomes"
research
|
4:
|
Case-series
(and poor quality prognostic cohort studies)
|
5:
|
Expert
opinion without explicit critical appraisal, or based on physiology, bench
research or "first principles"
|
Labels: doctor's file