chapter two BYO What is a clinical trial? In a clinical trial a group of people is randomly allocated to either a treatment group or a control group and a number of factors are measured before and after the treatment programme. In the case of coaching these factors could be goal attainment, anxiety, stress or depression, and ability to set and achieve goals. If the coaching or the treatment programme really does work, there should be a significant difference between the group that undergoes the programme and the group that doesn't.