What is the primary purpose of randomization in experimental studies?

The primary purpose of randomization in experimental studies is to ensure that treatment and control groups are alike in all respects except for the treatment itself. By randomly assigning participants to either group, researchers can effectively balance both known and unknown confounding variables across the groups. This helps to isolate the effect of the treatment being tested, making it more likely that any differences in outcomes can be attributed to the treatment rather than to some other factor.

Through randomization, the random assignment process reduces selection bias, thereby enhancing the internal validity of an experiment. It does not necessarily eliminate bias in observations, nor does it directly address the issue of placebo effects. The main aim is to create comparable groups to enhance the reliability of the results derived from the study. This allows for stronger conclusions regarding the efficacy of the treatment being examined.