Which statement about randomization is true?

Which statement about randomization is true?

• A. It helps ensure comparable groups by randomly assigning participants
• B. It guarantees identical groups
• C. It guarantees no confounding
• D. It is used only in cross-over trials

Answer: (B)

Randomization aims to create comparable groups by assigning participants to treatment arms purely by chance. This helps balance both measured and unmeasured factors across groups on average, so differences in outcomes are more likely due to the intervention itself rather than preexisting differences. But it doesn’t guarantee identical groups or completely eliminate confounding—smaller studies can still have imbalances by chance, and unmeasured confounders can remain. Randomization is used in many trial designs, including parallel-group trials and cross-over trials, not just in one type. So the statement that randomization helps ensure comparable groups by randomly assigning participants is the most accurate description.

Randomization aims to create comparable groups by assigning participants to treatment arms purely by chance. This helps balance both measured and unmeasured factors across groups on average, so differences in outcomes are more likely due to the intervention itself rather than preexisting differences. But it doesn’t guarantee identical groups or completely eliminate confounding—smaller studies can still have imbalances by chance, and unmeasured confounders can remain. Randomization is used in many trial designs, including parallel-group trials and cross-over trials, not just in one type. So the statement that randomization helps ensure comparable groups by randomly assigning participants is the most accurate description.