Odds Ratio Calculator
Calculate the odds ratio from a 2x2 contingency table
2x2 Contingency Table:
| Outcome (+) | Outcome (-) | |
|---|---|---|
| Exposed | ||
| Not Exposed |
About Odds Ratio
The odds ratio compares the odds of an outcome between two groups, commonly used in case-control studies and epidemiology.
Formula: OR = (a × d) / (b × c)
Interpretation:
- OR = 1: No association
- OR > 1: Exposure increases odds of outcome
- OR < 1: Exposure decreases odds of outcome
Note: OR approximates relative risk when outcome is rare (<10%).