What is the purpose of random assignment in research?

The purpose of random assignment in research is to reduce bias and confounding variables in group placement. By randomly assigning participants to different groups, the researcher ensures that each group is similar at the start of the experiment. This helps to control for both known and unknown factors that could influence the outcomes of the study. Consequently, any differences observed between the groups can be more confidently attributed to the treatment or intervention being tested, rather than to other extraneous variables.

Random assignment is crucial for establishing internal validity, as it helps ensure that the effects of the independent variable are isolated from other potential influences. This allows researchers to draw more reliable and valid conclusions about the cause-and-effect relationships being studied.