Writing the introduction and methods of a controlled trial

A controlled trial is an experimental study in which participants are assigned to receive one or more interventions (or no intervention), and the subsequent biomedical or health-related outcomes are compared in participants. The term controlled refers to the standard practice or placebo (substance with no active ingredient) to which the new intervention is compared within the trial. Randomized controlled trials (RCT) in which the participants are randomly assigned to treatment, i.e., intervention or control, are considered as gold standard by most because of the significant reduction in bias. RCTs methods can vary in a number of ways e.g., problem under study (disease or behavior), population (individuals, groups etc.), types of interventions (e.g., drugs, procedures, therapies etc.), design (e.g., parallel, crossover, cluster etc.), expected outcome (superiority, non-inferiority etc.), allocation concealment, blinding, analytical approach etc., the details of which are available elsewhere.