Topic 2

Question 1

Intention to treat

Answer 1

A value used to account for experimental participants who did not receive treatment due to lack of motivation, illness etc, or for control participants who did receive the treatment.

Question 2

Continuous outcomes- size of the intervention effect

Answer 2

The difference is means between the intervention and control groups. 
Take into account clinical significance 
Size of the confidence interval 
Determination of whether the results are
Clinically worthwhile

Question 3

Dichotomous outcomes- size of treatment effect

Answer 3

Need to consider:

• relative risk - the risk or probability of the event in the intervention group divided by that in the control group.
• relative risk reduction - the proportional reduction in an event of interest in the intervention group compared with the control group
• absolute risk reduction - the absolute arithmetic difference in event rates between the experimental and control groups.
• number needed to treat - the number of people needed to be treated to achieve the event of interest once.
• odds ratio- the odds of an event in the intervention group divided by the odds of an event in the control group. Usually expressed as a decimal proportion.