What method helps in ensuring that each subject has an equal chance of assignment in a study?

Randomization is a fundamental method in research design that ensures that each subject has an equal chance of being assigned to any of the experimental groups, including the control group. This process helps to eliminate selection bias and ensures that the groups are comparable at the outset of the study. By randomly assigning participants, researchers can be more confident that the results are due to the interventions being tested rather than pre-existing differences among the subjects.

This technique is crucial in providing a valid basis for statistical analysis, as it allows for the results to be generalized to a larger population. In randomized controlled trials, this method strengthens the internal validity of the study, making it a cornerstone of experimental research in fields such as music therapy and beyond.