Randomised control trial

Question 2

What is an randomised control trial

Answer 2

It is an experimental, prospective study

It is a study in which a number of similar people are randomly assigned to 2 (or more) groups to test a specific drug, treatment or other intervention.

One group (experimental) has the intervention being tested, the other (the comparison or control group) has and alternative, a dummy intervention (placebo) or no intervention at all

The groups are followed up to see how effective the experimental intervention was. Outcomes are measured at specific times and any difference in response between the groups is assessed statistically.

Question 3

What are RTC considered gold standard

Answer 3

They are considered gold standard because they are designed to eliminate bias and confounding that are common in observational studies

RCT are designed to ensure balance between the randomised groups so that any differences in outcome at the end of the trial must be attributable to the intervention

It permits the use of probability theory to express the likelihood that any difference in outcomes between treatment groups merely indicates chance.

Question 4

What are the different types of randomisation ?

Answer 4

there are several methods of randomisation:

• simple
  (E.g flip a coin)
• blocked
  (E.g dice roll)
• stratified
  (E.g produce separate blocked randomisation for each stratum(category)
• minimisation
  (E.g
• adaptive
  (E.g adjusts the probability of assignment to different treatment groups based on accumulating data during the trial
  Types:
• response adaptive randomisation
• covariate adaptive randomisation
• cluster
  (E.g randomise clusters instead of individuals, using geospatial analysis to ensure that clusters are appropriately randomised)

Question 5

Why do we blind participants?

Answer 5

Blinding prevents participants, caregivers, or outcomes assessors from knowing which intervention was received.

Double blinding is when neither participant nor investigators are aware of the treatment assigned.

Aims to remove responses, measurement or observer bias as an explanation for any differences in outcomes seen at the end of the study.

Question 6

What are the different types of RCT

Answer 6

Most common:
- parallel group trials (2 groups)

Others:
- parallel trial (>2 groups)
- factorial trials
- equivalence trials