Define "Randomized Controlled Trial (RCT)

Essay

Define "randomized controlled trial (RCT)."
Consider this description of an RCT: Espada and colleagues (2016) conducted a test of the efficacy of a smoking cessation program for adolescents in Spain. Prospective participants were recruited using a convenience sample, then randomly assigned to either a program condition or a control condition. The control condition consisted of adolescents placed on a waiting list for the program. Six months after the program, 8% of the program group had quit smoking, whereas no one in the control group had. This difference was statistically significant. After 1 year, 43% of the participants were available for follow-up data collection; this proportion was similar across both program and control conditions.
Making explicit reference to the concepts of internal and external validity, highlight several potential strengths and weakness of this study.