Tehran University of Medical Sciences Journal of Modern Rehabilitation 2538-385X 16 2 2022 04 01 105 107 Roger Watson Department of Nursing, School of Health Sciences, University of Hull, Hull, United Kingdom. Ahmad Reza Khatoonabadi Department of Speech Therapy, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran. 2021 04 19 2021 06 17 Dear Editor When people consider Randomized Controlled Trials (RCTs), they tend to focus on design issues, which is understandable. RCTs are an essential component of the arsenal of research designs and are the only research design whereby the true relationship between cause and effect can be discerned. https://jmr.tums.ac.ir/index.php/jmr/article/view/432