Definition

Clinical Trials are studies that evaluate the effectiveness and safety of treatments.

Although clinical trials often test the effects of drugs, they also test medical devices, and other forms of prevention and treatment, such as health promotion, methods of disease detection, surgery and physical therapies. Clinical trials are vital for reliable information about the effects of different treatments, ensuring that treatment options are effective and safe.

The results of controlled trials help to develop a sound evidence base, which doctors and patients can use when making treatment decisions. In offering a reliable evidence base, doctors can be more confident that they are using treatments that have been shown to have beneficial effects and that resources can be allocated to effective therapies.

A randomised controlled trial is a study in which people are allocated at random (by chance alone) to receive one of several clinical interventions. One of these interventions is the standard of comparison or control. The control may be a standard practice, a placebo ("sugar pill"), or no intervention at all. Someone who takes part in a randomised controlled trial (RCT) is called a participant or subject.

RCTs seek to measure and compare the outcomes after the participants receive the interventions. Because the outcomes are measured, RCTs are quantitative studies. In sum, RCTs are quantitative, comparative, controlled experiments in which investigators study two or more interventions in a series of individuals who receive them in random order. The RCT is one of the simplest and most powerful tools in clinical research.

In some instances, cluster randomisation methods are used where patients are allocated to a treatment by group rather than on an individual basis (e.g. by clinic, by town). Statistics should accurately represent the sample.

What are clinical trials?
Definition
Process for drugs
Regulation and guidance
Informed consent