Question

The risk among the exposed divided by the risk among the non-exposed is defined as:

• A. Relative risk
• B. Odds ratio
• C. Attributable risk
• D. None of the above

Hint:

A ratio (not a difference) of two incidences.

Answer 1

The Correct Option is A

Step 1: The measure described is a ratio of two risks, one in an exposed group and one in a non-exposed group.

Step 2: In epidemiology, relative risk (risk ratio) is defined as the ratio of the probability of an event occurring in an exposed group to the probability of the event occurring in a non-exposed group: \[RR = \frac{\text{incidence in exposed}}{\text{incidence in non-exposed}}.\]
Step 3: Attributable risk is instead the difference (subtraction) between the two incidences, and the odds ratio uses odds rather than risks, so they do not match the definition.

Step 4: Therefore the correct answer is Relative risk (option A).