You Are Interested in Studying Health Behaviors, Particularly Why Some

You are interested in studying health behaviors, particularly why some patients comply with their doctors' order to take the full course of a prescribed medication, whereas others stop taking the medication once they begin to feel better. You run an experiment to test whether people who write down their own dosing instructions are more compliant than those who have the doctor do it for them. Results reveal that having patients write their own dosing instructions has a significant impact on compliance. However, a colleague disputes your claim saying perhaps the severity of illness is what is affecting compliance behavior. Use your understanding of random assignment to respond to this concern.