Tutorial 1

Question 1

2 stages where confounding can be dealt with

Answer 1

Design stage

Analysis stage

Question 2

Confounding can be dealt with at the design stage of a study by…

Answer 2

…randomisation (in a randomised controlled trial), restriction, or matching (in a case-control study)

Question 3

confounding variables can be controlled for at the analysis stage…

Answer 3

…by stratification (splitting the analysis e.g. by age group), standardisation, or regression (building a statistical model)

Question 4

Attributable risk

Answer 4

measure of exposure effect that indicates, on an absolute scale, how much greater the frequency of disease in the exposed group is compared with the unexposed, assuming the relationship between exposure and disease is causal (an important assumption)
It is the difference between the incidence rate in the exposed and non exposed groups, i.e. it represents the risk attributable to the exposure of interest.
Attributable Risk = Incidence in the Exposed – Incidence in the Unexposed