Odds Ratio Calculator
2×2 contingency table: a=exposed/case, b=exposed/control, c=unexposed/case, d=unexposed/control
a (exposed, case)
b (exposed, control)
c (unexposed, case)
d (unexposed, control)
✓Odds Ratio
Odds Ratio
3.0000
ln(OR)
1.0986
95% CI
[2.044, 4.403]
OR = 1: no association | OR >1: positive association | OR <1: negative association
The odds ratio (OR) measures the association between an exposure and an outcome in case-control studies. An OR > 1 indicates increased risk; OR < 1 indicates reduced risk; OR = 1 indicates no association.
- 1OR = (a×d) / (b×c)
- 2a=exposed cases, b=exposed controls, c=unexposed cases, d=unexposed controls
- 395% CI: e^(ln(OR) ± 1.96×SE)
- 4SE = √(1/a + 1/b + 1/c + 1/d)
a=100, b=50, c=200, d=300=OR = (100×300)/(50×200) = 3.0
OR=1.5, CI=[1.1, 2.1]=50% increased odds; significant (CI excludes 1)
| OR value | Association | Meaning |
|---|---|---|
| < 1 | Negative | Exposure protective |
| = 1 | None | No association |
| 1.1–1.5 | Weak positive | Slight increased risk |
| 1.5–3.0 | Moderate | Meaningful association |
| > 3.0 | Strong | Strong association |
References
🔒
100% Gratuit
Sans inscription
✓
Précis
Formules vérifiées
⚡
Instantané
Résultats immédiats
📱
Compatible mobile
Tous les appareils