Simultaneous / Alternating Treatment Designs

1. Simultaneous / Alternating Treatment Designs

2. Also known as: • Multi-element baseline design • Multiple schedule design • Concurrent schedule design

3. Overview • Efficient for comparing effects of 2 or more treatments • Alternated in a variety of ways • A distinct stimulus is often associated with each treatment • Involves prediction, verification, and replication

4. Logic of Simultaneous or Alternating Treatments Design • Experimental control is demonstrated with different levels of response in different treatments • Allows for quick comparison • Stresses importance of evaluating individualized treatments

5. Design Variations • Single phase without no-treatment control condition • Single phase with one no-treatment control condition • Two phase with initial baseline • Three phase with baseline and final best treatment phase

6. Without No-Treatment Control Condition

7. With No-Treatment Control Condition

8. With Baseline and Final Best Treatment Phase

9. Design Advantages • Does not require treatment withdrawal • Speed of comparison • Minimizes irreversibility problem • Minimizes sequence effects • Can be used with unstable data • Can be used to assess generalization of effects • Intervention can begin immediately

10. Design Disadvantages • Multiple treatment interference • Unnatural nature of rapidly alternating treatments • Limited capacity (max. of 4 conditions) • Selection of treatments – should be significantly different from one another

11. Conclusions • Good way to examine a lot of options • Need to be careful to not do too many • Client may become overwhelmed • Client may become confused about what to do • You may lose track of what you are doing.