Randomized Controlled Trial (RCT) -
An RCT is an experimental study; that is the researchers introduce a variable with the intent of observing an outcome(s). However, in an RCT participants are randomly assigned to an experimental group (or multiple experimental groups), and compared to a randomly assigned control group (sham intervention or placebo). The control group gives baseline data to compare the experimental group against, reducing the likelihood that any trends noticed in the data were the result of confounding variables. More sophisticated research methods may include additional groups, for example experimental, experimental 2, control, placebo, nocebo, etc.
Example: In the study by Makofsky et al. (1) investigating the effect of joint mobilizations on hip abductor torque, participants were randomly assigned to either:
- Control Group - receiving sham therapy of grade I inferior mobilizations too gentle to have an effect on joint stiffness
- Experimental Group - receiving the therapeutic intervention being tested of Grade IV inferior mobilizations
- Makofsky, H, Panicker, S, Abbruzzese, J, Aridas, C, Camp, M, Drakes, J, Franco, C and Sileo R. (2007). Immediate effect of grade IV inferior hip mobilization on hip abductor torque: a pilot study. Journal of Manual and Manipulative Therapy, 15(2), 103-111