Table 2 Statistical assessment for specific Brad Hill criteria for causation
Criteria | Statistical assessment | Qualification of strength of relationshipa |
|---|---|---|
Association and experiment | Odds ratio | Protective:<1.0 |
Weak: 1.0–2.4 | ||
Moderate: 2.5–3.9 | ||
Strong:>4.0 | ||
Relative risk | Protective:<1.0 | |
Hazard Ratio | Weak: 1.0–1.9 | |
Prevalence ratio | Moderate: 2.0–2.9 | |
Incidence rate ratio | Strong:O3.0 | |
T test | Clinically significant:>10% change in effect | |
Consistency | Sackett’s strength of evidence | Strong:>75% of studies (at least two high quality) |
Dose response | Pearson correlation | Protective:<0.0 |
Weak: 0.1–0.29 | ||
Moderate: 0.3–0.49 | ||
Strong:>0.5 | ||
Logistical regression | Protective:<0.0 | |
Weak: 0.1–0.29 | ||
Moderate: 0.3–0.49 | ||
Strong:>0.5 | ||
Confident intervals on estimates | Significant: nonoverlapping | |
Trend: overlapping confidence interval |