Lectures 8-10: Measures of Association

Question 1

Incidence Risk (IR)

Answer 1

Proportion: probability of outcome in exposed or non-exposed

A/(A+B); C/(C+D)

Question 2

Risk Ratio (RR)

Answer 2

Risk in exposed/Risk in non-exposed

Question 3

Absolute Risk Reduction (ARR)

Answer 3

Absolute difference in risks

Risk ratio exposed - Risk ratio not-exposed

Question 4

Relative Risk Reduction (RRR)

Answer 4

Absolute Risk Reduction/Risk of unexposed

Question 5

Number Needed to Treat (NNT)

Answer 5

1/Absolute Risk Reduction

Question 6

Odds of exposure in Cases/Controls

Answer 6

Cases: A/C; Controls B/D

Question 7

Odds Ratio (OR)

Answer 7

Odds of exposure in Cases vs Odds of exposure in Controls

A/C divided by B/D