Mathematics
Design of Experiments: The Role of Randomization
Quick fact
Randomization is so powerful that it allows researchers to draw cause-and-effect conclusions without even knowing about potential confounding variables, because it makes groups comparable on average across all factors—measured and unmeasured alike.
Why this is interesting
Imagine two groups of patients: one receives a new drug, the other a placebo. If the drug group gets better, is it because of the drug, or because they were younger and healthier to begin with? Randomization is the tool that makes the answer trustworthy.