Randomization

Being assigned to one group or another purely by chance, like a coin flip, so the comparison stays fair.

Randomization means that when a trial is comparing two or more approaches, a computer assigns you to a group purely by chance — a bit like flipping a coin. Neither you nor your doctor picks which group you land in.

Why do it this way? It keeps the comparison honest. If people chose their own group, the groups might end up different in ways that muddy the results. Letting chance decide makes the groups as similar as possible, so any difference at the end can be trusted to come from the treatment itself. One group is often the control group. You’ll be told before you join that a trial uses randomization.