What is the primary goal of random assignment in research?

The primary goal of random assignment in research is to minimize preexisting differences between participants in different groups. By randomly assigning individuals to either the experimental or control group, researchers aim to ensure that any preexisting characteristics—such as age, gender, socio-economic status, or prior experiences—are evenly distributed across all groups. This process increases the likelihood that the groups are comparable at the start of the experiment, allowing any observed effects to be attributed more confidently to the treatment or intervention rather than to inherent variations between the participants. Essentially, random assignment helps in establishing internal validity by controlling for confounding variables that could skew the results.