Ratio of Event Odds

Compare event odds for two independent groups.

Your numbers

Ratio between the event odds

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Use positive cell counts. Large-sample interval fit no reliable for small samples; e no apply continuity correction.

Formula

Use OR = ad/(bc) and bounds exp[ln(OR)±1.96√(1/a+1/b+1/c+1/d)]. a and b na group A event and non-event counts; c and d na group B counts. Di logarithmic interval dey use normal approximation and need positive counts.

Compare event odds for two independent groups.

Example wey show the calculation

Events for group A: 20
Non-events for group A: 80
Events for group B: 10
Non-events for group B: 90

Ratio between the event odds: 2.25
Approximate lower end for 95% interval: 0.994294892282
Approximate upper end for 95% interval: 5.09154782882

Where e fit work and limits

Use positive cell counts. Large-sample interval fit no reliable for small samples; e no apply continuity correction.

We check inputs for missing values and allowed ranges. Result wey pass the finite numeric range no go show. Rounding affect wetin display, while calculation use the model numeric precision.

Check your units and assumptions before you rely on result. Changing label no convert currency or physical unit.

Version of di formula: 44d5b26f5631 · Example don get check: 2026-10-30

Method