Control Groups: Linking Evidence to Practice.

Despite the fact that a randomized controlled trial (RCT), by definition, can't exist without one, the control group is the forgotten stepchild of the RCT. The nature of the control group in part determines the research question that the RCT answers, and only by understanding the precise question can the results be sensibly interpreted. Given that RCTs always measure relative effectiveness of the treatment and control interventions, it is important that interpretation reflects this. That means that conclusions that a treatment is effective should always state, "compared to the control intervention." J Orthop Sports Phys Ther 2018;48(11):905-906. doi:10.2519/jospt.2018.0706.