In which experimental design are subjects randomly assigned to treatment conditions?

The random group design is a type of experimental design that involves randomly assigning subjects to different treatment groups or conditions. This random assignment helps ensure that the groups are comparable at the start of the experiment, minimizing the impact of confounding variables and making it more likely that any observed effects can be attributed to the treatment itself rather than pre-existing differences between participants.

In this design, participants are randomly allocated to various conditions, eliminating biases that might arise from factors such as participant characteristics or pretesting. This enhances the internal validity of the study and the reliability of the results, allowing researchers to draw more accurate conclusions about the effects of the treatments being investigated.

Other designs, such as single subject ABA, pretest-posttest, and matched pairs, utilize different methodologies that do not involve random assignment of subjects to conditions in the same manner. For instance, a single subject ABA design focuses on observing the behavior of a single participant over time under different conditions, while a matched pairs design attempts to pair participants with similar characteristics before assigning them to conditions, rather than relying on randomization. Pretest-posttest designs typically involve measuring outcomes before and after an intervention but do not emphasize random assignment of participants to various groups.