What best defines 'randomization' in biomedical research?

• A. It is a method of distributing animals among the different groups needed for the study
• B. It is a method used to collect data
• C. It is a method used to blind investigators to treatment
• D. It is a method used to calibrate equipment

Answer: (A)

Randomization means assigning animals to experimental groups by chance so each animal has an equal opportunity to be placed in any group. This helps ensure the groups start out similar in both measured and unmeasured factors, reducing selection bias and making it more likely that observed differences are due to the treatment rather than preexisting differences. It’s not about how data are collected, nor about blinding investigators to treatment, nor about calibrating equipment. Therefore, distributing animals among the different groups needed for the study best defines randomization.