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 a
fair 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.