Randomised Controlled Trials

Question 1

What is a Randomised Controlled Trial?

Answer 1

Two groups, one intervention and one control and compare results. It is prospective which is good. Complex and can be impossible

Question 2

What is the design of a RCT?

Answer 2

There’s an intervention. Ppts randomised to groups. Attention arm (control group) sometimes.

Question 3

What are the hypotheses used for RCT?

Answer 3

Null hypothesis and Alternate hypothesis. Null hypothesis states that there’s no difference between control and intervention arms

Question 4

What are the inclusion and exclusion criteria for the population?

Answer 4

When the target population is defined, we exclude those who aren’t relevant and a sample is drawn from the inclusion criteria population

Question 5

What is probability and non-probability sampling in order to get a sample?

Answer 5

Probability sampling - gives an unbiased sample- everyone in the inclusion criteria has a chance of selection
Non-Probability sampling - non random and the chance of being selected can’t be estimated

Question 6

What are the 4 types of probability sampling to get a sample?

Answer 6

Simple random, stratified random, cluster and systematic random

Question 7

What are the factors affecting the sample size?

Answer 7

Population factors (population similarity, attrition, rate of event), Design, Measurement, Practical factors.

Question 8

What is a power calculation?

Answer 8

It is done prior to a RCT, done to calculate the sample size needed to power the trial to detect the required differences in outcome

Question 9

What are the different types that we randomly allocate ppts to trial groups?

Answer 9

Simple randomisation, block randomisation and stratified randomisation

Question 10

What are the different forms of blinding in RCTs?

Answer 10

Single blind and double blind