A Randomised Controlled Trial (RCT) is a type of scientific experiment commonly used in healthcare and social sciences to assess the effectiveness of interventions. In an RCT, participants are randomly assigned to one of two or more groups: an experimental group receiving the intervention and a control group receiving a placebo or standard treatment. The randomisation minimises bias, ensuring that differences between groups can be attributed to the intervention itself rather than other variables. RCTs are considered the gold standard for evaluating the efficacy and safety of new treatments, procedures, or interventions.
Therapy (Treatment) questions, Prevention questions, Diagnosis questions.
| Study Type | Description |
|---|---|
| Single-Blind RCTs |
Participants do not know which group they are in (e.g., experimental drug or placebo). Example: Kamarudin, S. S., Idris, I. B., Sharip, S., & Ahmad, N. (2025). LoVE4MUM Mobile App to Prevent Postpartum Depression: Protocol for a Pilot Randomized Controlled Trial. JMIR research protocols, 14, e63564. https://doi.org/10.2196/63564 Full Text |
| Double-Blind RCTs |
Participants and researchers are unaware of who receives the treatment or placebo, reducing bias. Example: Kunze, K. N., Madjarova, S., Olsen, R., Smolarsky, R., Mehta, S., Baldwin, R., Ranawat, A. S., Nawabi, D. H., Kelly, B. T., & Nwachukwu, B. U. (2025). Intravenous Tranexamic Acid Does Not Improve Visual Field Clarity During Hip Arthroscopy: A Double-Blind, Randomized, Placebo-Controlled Trial. Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association, S0749-8063(25)00012-X. Advance online publication. https://doi.org/10.1016/j.arthro.2025.01.008 Abstract Full Text via Clinical Key |
| Triple-Blind RCTs |
Participants, researchers, and data analysts are unaware of group assignments, further minimising bias. Example: Ben Itzhak, N., Stijnen, L., Kostkova, K., Laenen, A., Jansen, B., & Ortibus, E. (2025). The effectiveness of an individualised and adaptive game-based rehabilitation, iVision, on visual perception in cerebral visual impairment: A triple-blind randomised controlled trial. Research in developmental disabilities, 156, 104899. https://doi.org/10.1016/j.ridd.2024.104899 Full Text |
| Parallel Group Trials |
Groups or clusters are randomised to study conditions, and observations are taken from members without cross-over between groups or study arms. Example: Yıldırım Ayaz, E., Mesci, B., Üner, Ö. E., Kaya, F. N., Dincer, B., İşman, F. K., & Oğuz, A. (2025). The effect of exercise on GDF-15 levels in individuals with prediabetes: A randomized controlled trial. Journal of diabetes investigation, 10.1111/jdi.14404. Advance online publication. https://doi.org/10.1111/jdi.14404 Full Text |
| Pragmatic RCTs |
Mimic usual clinical practice to inform real-world decision-making by patients, clinicians, and policymakers. Assess the effectiveness of available medicines. Example: Stephens, K. A., van Eeghen, C., Zheng, Z., Anastas, T., Ma, K. P. K., Prado, M. G., Clifton, J., Rose, G., Mullin, D., Chan, K. C. G., & Kessler, R. (2025). Intervention Stage Completion and Behavioral Health Outcomes: An Integrated Behavioral Health and Primary Care Randomized Pragmatic Trial. Annals of family medicine, 23(1), 35–43. https://doi.org/10.1370/afm.230576 Full Text |
Further information
Spieth, P. M., Kubasch, A. S., Penzlin, A. I., Illigens, B. M., Barlinn, K., & Siepmann, T. (2016). Randomized controlled trials - a matter of design. Neuropsychiatric disease and treatment, 12, 1341–1349. https://doi.org/10.2147/NDT.S101938 Full Text
Completed and published clinical trial results can be sourced using databases such as Medline or Embase. However, currently running clinical trials for particular interventions may provide useful preliminary data, protocol, findings and contact information for researches associated with the trial. Try searching some of the major sites listed on the grey literature guide
Messier, S. P., Mihalko, S. L., Beavers, D. P., Nicklas, B. J., DeVita, P., Carr, J. J., Hunter, D. J., Lyles, M., Guermazi, A., Bennell, K. L., & Loeser, R. F. (2021). Effect of High-Intensity Strength Training on Knee Pain and Knee Joint Compressive Forces Among Adults With Knee Osteoarthritis: The START Randomized Clinical Trial. JAMA, 325(7), 646–657. Full Text