Parallel Group Design
A parallel group design is an experimental study design in which each subject is randomized to one of two or more distinct treatment/intervention groups. Those who are assigned to the same treatment are referred to as a treatment group.
While the treatments that these groups receive differ, all groups are treated as equally as possible in all other regards, and they complete the same procedures during the study. This parallel activity on the part of the groups of individuals is captured in the term “parallel group design.”
The term controlled study is often heard in this context. One group will receive the treatment of interest and another group a control treatment, against which responses during and at the end of the treatment intervention are compared. Going one step further, the term concurrently controlled study makes clear that the different groups take part in their respective treatment arms at the same time. If all of the...