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