Introduction to Epidemiology 6th Edition by Ray M Merrill

Exercise 15

Match the types of ratio in the left column with the types of study in the right column.

Ratio	Study
__ Rate ratio	a. Case-crossover
__ Risk ratio	b. Case control
__ Odds ratio (paired data)	c. Cohort involving attack rates
__ Odds ratio (unpaired data)	d. Cohort involving person-time rates

Step 1 of 4

In cohort studies, when person-time is involved to calculate the ratio between exposed and unexposed persons then rate ratio is used. The formula is as follows:

Where, a is exposed cases, c is unexposed cases, PTe is person-time in exposed group, and PTo is person time in unexposed group.

Hence, the correct match for rate ratio is.