Advantages
There are three major advantages to single-subject designs.

1. One major advantage is the ability to focus on individual performance. A classic example is in the field of learning. If you plotted performance on a memory task for a group of subjects, you might conclude that learning is a gradual process. However, if you plotted the learning of an individual subject, you might find that learning takes place in an all-or-nothing fashion.
   
   
2. Another advantage to the use of this design in clinical work is that you don't leave individuals untreated in control groups.
   
   
3. A third advantage is that single-subject designs allow flexibility in design. If a treatment is not working, it is easy to change.