A clinical trial is a medical study involving participants who volunteer to take part. Clinical trials are used in all areas of medicine and are carried out for many different reasons. They could be testing a new treatment by comparing it to the best current treatment available or they could be used in testing new technology or procedures. From clinical trials we can find out if a new treatment is safe, if it is better than the current treatment and we can find out what the side-effects of the treatment are.
When we do not know which way of treating patients is best, we need to make a comparison. An important part of making afair comparison is ‘randomisation’. Most large trials are randomised. The decision about which treatment a patient receives is random – based on chance. This is done by a computer programme, not the patient or the doctor. This is called randomisation. Randomisation ensures that the two (or more) groups of people in a trial are as similar as possible, except for the treatment they receive. Therefore, randomisation means that the results are more reliable. The process of randomisation is usually carried out by a computer-based system.
Randomisation is also the best way of ensuring that the results of trials are not biased by the way treatments are selected. For example, if a doctor chose which treatment a patient should receive as part of a trial, she or he might give the new treatment to sicker patients, or to younger patients. This would make the results of a trial unreliable. Randomisation helps prevent this kind of bias.