Table 1.
The meaning of the OCEBM levels of evidence
| The interpretation (below) of the meaning of levels of evidence (left column) is the opinion of the GDC, based on the OCEBM recommendation grading system. | |||
|---|---|---|---|
| Evidence level | Study results are … | You interpret results … | Clinical meaning |
| 1a | almost certain | objectively | Recommendations directly supported by evidence are very likely reliable and valid. |
| 1b | |||
| 1c | |||
| 2a | strongly suggestive | objectively | Recommendations directly supported by evidence are likely reliable and valid. |
| 2b | |||
| 2c | |||
| 3a | |||
| 3b | |||
| 4 | suggestive | objectively | Recommendations directly supported by evidence may be reliable and valid. |
| 5 | inconclusive | objectively | Reliability and validity of recommendations uncertain. |
| subjective extrapolation from Levels 1–5 | |||
Adapted from the OCEBM levels of evidence (May 2001).7 Documents at the referenced web-site were used to discriminate between good and poor quality studies of the same design.