Statistics in Practice Flashcards
What do we need in clincial trials?
- Randomization
- Blinding
- Intention to treat analysis
- Per protocol analysis
What is randomisation in an clinical trial?
- Random allocation into an experimental group and a control group
- Avoids selection bias
- Successful randomisation makes different groups have similar characteristics at baseline
What is blinding in an clinical trial?
- A blind experiment is an experiment in which information about the test is masked (kept) from the participants
- Aim: to reduce or eliminate bias
- Bias may be intentional or unconscious
Can blind patient and/or doctor
don’t know what treatment they are on
What are the different types of blinding in clinical trials?
Unblinded / open label - All parties are aware of the treatment allocation
Single blind / single-masked- Participants are unaware of the treatment they receive
Double blind / double-masked - Participants and clinicians / data collectors are unaware of the treatment participants receive
Triple blind - Participants, clinicians / data collectors and data analysts are all unaware of the treatment participants receive
more blinding you would expect less bias
What is intention to treat (ITT) analysis?
Important
- Thoes who are intended to have the treatment
- ITT analysis includes every subject who is randomized according to randomized treatment assignment
- Ignores noncompliance, protocol deviations, withdrawal, and anything that happens after randomization
- 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 randomized subjects.
can cause bias
What is per protocol analysis?
A subset of the ITT population who completed the study without any major protocol violations
-e.g a subset who have taken full dose of the tretment
- smaller sub-group
