Randomised controlled trial (RCT)
Short definition
A randomised controlled trial is a study in which participants are allocated by chance to the intervention being studied or to a control group, so that outcomes can be compared without the choice influencing who receives what.
In plain language
In an RCT, chance (a computer-generated draw, for example) decides who receives the intervention and who is in the comparison group. As a result, the two groups tend to be similar in everything except the intervention, and differences in outcomes can be attributed to it with more confidence. For example, an RCT might compare children who use virtual reality during a blood draw with children who receive usual care, measuring the pain both groups report.