Single Subject Research Designs Chapter 14 1 Single
Single- Subject Research Designs Chapter 14 1
Single- subject designs, or single- case designs, are research designs that use the results from a single participant or subject to establish the existence of cause- and- effect relationships. 2
Phases and phase changes A phase is a series of observations of the same individual under the same conditions. When no treatment is being administered, the observations are called baseline observations. 3
Visual Inspection Techniques • Unfortunately, there are no absolute, objective standards for determining how much of a change in pattern is sufficient to provide a convincing demonstration of a treatment effect. • The most convincing results occur when the change in pattern is immediate and large. 4
4 types of change • • Change in average level Immediate change in level Change in trend Latency of change. 5
Change in average level Immediate change in level Change in trend Latency in Change 6
The problem with single subject design 7
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THE ABAB REVERSAL DESIGN • the majority of single- subject research studies use ABAB design; • consists of four phases: a baseline phase ( A), followed by treatment ( B), then a return to baseline ( A), and finally a repetition of the treatment phase ( B). 9
Effective A= no treatment 10
Not Effective 11
Variations on the ABAB Design 12
1 - B&B 1 not working use C 13
2 - B not working add C B= Graduated exposure C= Reinforcement 14
3 - MULTIPLE- BASELINE DESIGNS 1 - Eliminates the need for a return to baseline and therefore, 2 - Is particularly well suited for evaluating treatments with long- lasting or permanent effects. 15
3 - MULTIPLE- BASELINE DESIGNS Examples A therapist uses the same method for 2 different behaviors (across behaviors) For one behavior that is exhibited in 2 different situations. (across situations) A teacher uses the same method on 2 different individuals (across subjects) 16
Person 1 Person 2 2 different students 17
Yelling Crying 2 different behaviors 18
School Home 2 different situations. 19
Weaknesses of the Multiple- Baseline Design? 20
4 - Dismantling design A dismantling design, also called a componentanalysis design, consists of a series of phases in which each phase adds or subtracts one component of a complex treatment to determine how each component contributes to the overall treatment effectiveness. 21
Example 22
5 - The Changing- Criterion Design • The criterion level is changed from one phase to the next. 23
Smoking Treatment 24
6 -The Alternating- Treatments Design • In an alternating- treatments design, also called a discrete-trials design, two ( or more) treatment conditions are randomly alternated from one observation to the next. 25
Example - Alternate weeks 26
- Slides: 26