Professor Cheryl Dissanayake
Director, Olga Tennison Autism Research Centre, La Trobe University
In a multiple baseline design, the interventions for each behaviour are staggered.
The baseline for the 2nd behaviour continues until a change in the 1st behaviour is evident (minimum 3 data points).
If a change in the 2nd behaviour is observed, following baseline but prior to intervention for the 2nd target behaviour, than you have failed to demonstrate experimental control (i.e., the changes may have occurred because of an outside factor).
Look at the following graph and answer the following questions:
- Has experimental control been demonstrated?
- If not, why not?
Think of 5 reasons why the two behaviours may have both changed in session 5, despite intervention only being provided for the 1st behaviour.