Chapter 5

Question 1

What number is the reference point for interpreting relative differences

Answer 1

Reference point is always 1

Question 2

What does a ratio or relative measure tell us

Answer 2

How many times mroe likely it is that someone who is exposed to something will develop the idease compared (relative) to someone who is not exposed

Question 3

How do we know the strenght of the association between the exposure and the outcome

Answer 3

the further the ratio departs from 1, the stornger the association is. eg .5 and 1.5 are same but one is bad one is better

Question 4

When would Rate Ratios be used

Answer 4

BASED ON the ratio of incidence rates
for longitudinal studies, Cohort & RCT
RR= Incidence rate in exposed/ unexposed

Question 5

Relative risk ( Risk Ratio)

Answer 5

Based on ratio of incidence PROPORTION
Risk Ratio= Incidence proportion in exposed/unexposed

Question 6

When do we use Odds Ratios

Answer 6

For use in case-control studies, also cross-sectional studies

Question 7

In a cross sectional study, the odds ratio is a good estimate of the relative risk if the outcome is rare. What is a rare outcome

Answer 7

<5%. It will overestimate the RR if the outcome is common

Question 8

Risk difference can tell us what?

Answer 8

The backgroud rate (eg the risk everyone has for living and not directly being exposed) think of the bar graph example related to smoking.

Question 9

What are attributable fractions

Answer 9

Refers to the proportion of the disease in the exposed group that would not have occured in the absence of the exposure. Can be based of the indidence rate or proportion