CA part two

Question 1

Validity

Answer 1

Validity refers to the soundness or rigour of a study. A study is valid if the way it is designed and carried out means that the results are unbiased – that is, it gives you a more trustworthy estimate of clinical effectiveness.”

Question 2

Internal validity

Answer 2

An RCT is internally valid if it truthfully reports the intervention effect

Question 3

External validity

Answer 3

An RCT is externally valid if the findings can be generalised to other contexts

Question 4

How do RCTs attempt to limit bias?

Answer 4

Randomly allocating participants to groups
Blinding participants, investigators and outcome assessors to that allocation (where possible)
Including a control or comparison group