Table 1 Gray scale of the strength of evidence
From: What works to meet the sexual and reproductive health needs of women living with HIV/AIDS
| Type | Strength of evidence |
|---|---|
| I | Strong evidence from at least one systematic review of multiple well-designed, randomized controlled trials. |
| II | Strong evidence from at least one properly designed, randomized controlled trial of appropriate size. |
| III | Evidence from well-designed trials without randomization: single, group, pre-post, cohort, time series, or matched case-control studies. |
| IV | Evidence from well-designed, non-experimental studies from more than one centre or research group. |
| V | Opinions of respected authorities, based on clinical evidence, descriptive studies or reports of expert committees. |