given a new drug, while participants in the control condition receive a placebo. Ideally, this is done in a “double-blind” setting, where neither the participant nor the person delivering the treatment or otherwise interacting with the participant knows which condition the participant is assigned to. Randomization is key here: By letting chance determine who gets which treatment, characteristics of the participants (e.g. age, sex, severity of symptoms, etc.) will not be tied to the treatment they get. 