Lecture 13

Question 1

what are measures of association used for?

Answer 1

• describing the importance of key factors in the development of a disease of health problem
• expressing the link between exposure and outcome
• absolute and relative measures

Question 2

what is the odds (OR) ratio?

Answer 2

• measure of association that expresses the ratio of two odds regarding the relationship between exposure and disease
• • used in case control and cohort studies

OR = (ad)/(bc)

Question 3

what is the risk ratio (RR)?

Answer 3

• divides the risk of the outcome in the exposed group by the risk of the outcome in the unexposed group

RR = (risk in the exposed) / (risk in the unexposed)

or

RR = (A/(A+B)) / (C/(C+D))

Question 4

what is the prevalence ration (PR)?

Answer 4

• divides the prevalence of the outcome in the exposed group by the prevalence of the outcome in the unexposed group

PR = (A/(A+B)) / (C/(C+D))