Statistics in practice I and II

Question 1

Features of randomisation

Answer 1

-Random allocation into an experimental group and a control group
-Avoids selection bias
-Successful randomisation makes different groups have similar characteristics at baseline

Question 2

Features of blinding

Answer 2

-Information about the test is masked (kept) from the participants
-Aim is to reduce or eliminate bias
-Bias can be intentional or unconscious

Question 3

What are the 4 types of blinding

Answer 3

Question 4

What is unblinding?

Answer 4

-The disclosure to participants or study team of which treatment participants received during the trial

Question 5

What is intention to treat (ITT) analysis?

Answer 5

-ITT analysis includes every subject who is randomised according to randomised treatment assignment
-Ignores noncompliance, protocol deviations, withdrawal, and anything that happens after randomisation
-ITT analysis maintains prognostic balance generated by randomisation
-Estimate of treatment effect is generally conservative
-A better application of the ITT approach is possible if complete outcome data are available for all randomised subjects

Question 6

What is per protocol analysis?

Answer 6

-A subset of the ITT population who completed the study without any major protocol violations