 We're back with an ABA design. An ABA design is a three-phase experimental single-subject research design that starts with a baseline condition, A, followed by an intervention condition, B, and then a return to baseline condition, A. The criteria for exiting each condition is stability in the behavior. The behavior becomes stable in the A condition, then we go into the B condition, and again stay there until the behavior is stable, and we revert back to the A condition to make a comparison between this baseline and that baseline. A couple of examples for you. We could stick with the food example where you start with your traditional diet here during your A condition. You switch in your B condition to a new diet and you return back to your original diet at the end to see how the difference is, see if there were any differences between pre and post if you will. A second example could be where we have typical classroom rules, then we switch the classroom rules and implement a token economy, and then we remove that token economy to go back to the original classroom rules.