Stratification
Splitting participants into subgroups first, so groups stay balanced.
Learning
What it means
Stratification divides participants by a characteristic — such as age band or disease stage — and randomises within each group, so the arms stay balanced on that characteristic.
Why it matters if you take part
It makes the comparison fairer by ensuring one arm does not end up with all the more or less severely affected participants.
Related terms
This explains how clinical research works. It is not medical advice and does not describe any specific condition or treatment. Only a trial site can determine whether someone can take part in a study.