Interactive demo
Randomization in action
Click Randomize to randomly assign 50 patients into two groups — and notice how their characteristics end up (almost) balanced, even though no one chose who goes where. That is the quiet engine behind every randomized controlled trial.
Try it yourself
Each circle is a patient. Colour shows symptom severity, the symbol shows sex, and a dashed border means a comorbidity is present.
High symptom severity
Low symptom severity
♀ Female
♂ Male
Has comorbidity
Covariate balance after randomization