A trial is a way to test something. So, a medical trial can be used to test treatments.

For example, if a new medicine is better than what is used at the moment or how safe a treatment is.

Trials can be different sizes, from a single set of patients in one city, to patients all over the country and abroad, in many research centres.

Usually in a trial, some patients receive one treatment while others receive another.

The decision about which patients receive which treatment, is usually made by computer.

This is called randomisation. So the patient, nurse or doctor don’t make the decision.

Randomisation means each treatment is given to a similar mix of patients to make sure the results are not due to anything else, like their age or where they live.

Usually the patient, nurse or doctor will only find out which treatment a patient has received at the end of the trial.

We might think a new treatment is going to be better than what is used at the moment.

But we cannot know until we test it in a trial.

So trials are needed to compare treatments, and find out what works best.

This helps us improve the care given to patients, including children and teenagers.

For patients there are positives about being in a trial.

The results from trials can also help other patients as well as patients in the future, by finding out which treatments work best.

This means that many treatments you are given have already been tested safely in trials with other people.

Trials usually involve lots of different people.

You’ll meet some of these people if you take part in a trial.

Some of them work behind the scenes and you won’t even see them.

The principal investigator, sometimes called the chief investigator, leads the study, and this is likely to be a doctor or researcher.

A research nurse or study nurse will usually look after you during the trial and collect information about you.

Sometimes this work is done by the doctor looking after you, your GP or the hospital doctor.

Scientists and researchers study your blood samples and the results of the tests.

The data manager enters this data into the computer.

The statistician will analyse the data to make sure the maths is right.

They all work together as a team to make sure the trial runs well.