ecology and steps

1. LEVELS OF EVIDENCES
BY BHARTI SINGH

2. LEVEL 1
• Evidence from a systematic review or meta-analysis of all relevant RCTs
(randomized controlled trial) or evidence-based clinical practice guidelines based
on systematic reviews of RCTs or three or more RCTs of good quality that have
similar results

3. LEVEL 2
• Evidence obtained from at least one well designed RCt

4. LEVEL 3
• Evidence obtained from well-designed controlled trials without randomization

5. LEVEL 4
• Evidence from well designed case-control or cohort studies

6. LEVEL 5
• Evidence from systematic reviews of descriptive and qualitative studies (meta
synthesis)

7. LEVEL 6
• Evidence from a single descriptive or qualitative study

8. LEVEL 7
• Evidence from the opinion of authorities and/or reports of expert committees

9. DIFFERENT TYPES OF CLINICAL QUESTIONS ARE
BEST ANSWERED BY DIFFERENT TYPES OF
RESEARCH STUDIES. YOU MIGHT NOT ALWAYS
FIND THE HIGHEST LEVEL OF EVIDENCE (I.E.,
SYSTEMATIC REVIEW OR META-ANALYSIS) TO
ANSWER YOUR QUESTION. WHEN THIS HAPPENS,
WORK YOUR WAY DOWN TO THE NEXT HIGHEST
LEVEL OF EVIDENCE.