Types of Trial Design
1. Non-randomised Controlled Clinical Trial Designs
In non-randomised controlled trials, participants are allocated into treatment and control arms by the investigator. It is appropriate to use a non-randomised controlled trial design when the act of random allocation may reduce the effectiveness of the intervention.
Non-randomised controlled trials have the potential to study two groups that are not strictly comparable. However, there are different types of controls that can be used in non-randomised trials:
- Control groups can be concurrent controls or historical controls.