Main purpose of Randomisation is
**Core Concept**
Randomization is a fundamental concept in clinical trials and research studies, aiming to minimize bias and ensure the internal validity of the results. It involves assigning participants to different groups, such as treatment or control groups, in a way that is unpredictable and not related to any specific characteristic of the participants.
**Why the Correct Answer is Right**
Randomization helps to prevent selection bias by distributing both known and unknown confounding variables evenly across groups. This is achieved through the use of randomization algorithms, such as block randomization or stratified randomization, which ensure that each participant has an equal chance of being assigned to any group. Randomization also helps to reduce the risk of confounding variables by minimizing the differences between groups in terms of demographic and clinical characteristics.
**Why Each Wrong Option is Incorrect**
**Option A:** This option might suggest that randomization is used to ensure that groups are similar in terms of demographic characteristics, but this is not the primary purpose of randomization.
**Option B:** This option is incorrect because randomization is not used to assign participants to groups based on their disease severity or other specific characteristics.
**Option C:** This option might suggest that randomization is used to increase the sample size, but this is not the main purpose of randomization.
**Clinical Pearl / High-Yield Fact**
A key benefit of randomization is that it allows researchers to make causal inferences about the relationship between the intervention and the outcome, which is essential for establishing the efficacy and effectiveness of treatments.
**Correct Answer: C. To prevent selection bias and ensure internal validity.**