Question:medium
The difference between the incidence in the exposed and the non-exposed group is best given by:
The difference between the incidence in the exposed and the non-exposed group is best given by:
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The word difference signals a subtraction of incidences, not a ratio.
Updated On: Jun 23, 2026
- Relative risk
- Attributable risk
- Population attributable risk
- Odds ratio
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The Correct Option is B
Solution and Explanation
One keyword cracks this: difference. In epidemiology, a difference between two incidences means subtraction, while ratio measures mean division. Sort the options on that line.
Attributable risk is the subtraction measure: $AR = I_{exposed} - I_{non-exposed}$. It quantifies how much of the disease burden in the exposed is due to the exposure itself, usually given as a percentage in a cohort study.
Everything else is a ratio. Relative risk ($a$) divides the two incidences, $I_{exposed}/I_{non-exposed}$. Odds ratio ($d$) divides odds and is the case-control surrogate for RR. Population attributable risk ($c$) scales the AR up to the whole community, factoring in how common the exposure is, so it is not the simple two-group difference.
The plain difference between exposed and non-exposed incidence is attributable risk, option $b$.
Ref: Park's PSM, 25th ed., p. 86.
Attributable risk is the subtraction measure: $AR = I_{exposed} - I_{non-exposed}$. It quantifies how much of the disease burden in the exposed is due to the exposure itself, usually given as a percentage in a cohort study.
Everything else is a ratio. Relative risk ($a$) divides the two incidences, $I_{exposed}/I_{non-exposed}$. Odds ratio ($d$) divides odds and is the case-control surrogate for RR. Population attributable risk ($c$) scales the AR up to the whole community, factoring in how common the exposure is, so it is not the simple two-group difference.
The plain difference between exposed and non-exposed incidence is attributable risk, option $b$.
Ref: Park's PSM, 25th ed., p. 86.
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