1. Applied Behavior Analysis for Teachers
Chapter 5:
Single-Subject Designs

2. Chapter Overview Variables and Functional Relations
Basic Categories of Designs
Single-Subject Designs
AB Design
Reversal Design
Changing Criterion Design
Multiple Baseline Design
Alternating Treatment Design
Changing Condition Design
Evaluating Single-Subject Designs
Action Research and Single-Subject Design Tools

3. Dependent and Independent Variables
The behavior targeted for change.
Independent Variable:
The intervention being used to change behavior.
Functional Relation:
A functional relation is said to exist if the dependent variable systematically changes in the manipulation of the independent variable.

4. What is the Dependent and Independent Variable?
To increase compliance in vocational settings by implementing a token reinforcement system.
Use picture prompts with students with severe disabilities to increase instruction-following skills.
Students will increase their organizational skills by outlining their daily activities on a schedule checklist for six weeks.
The use of graduated guidance will enable the student to eventually feed himself.
Increase reading skills by two grade levels following instruction using the “I’m A Better Reader” program in combination with time delay.
Implement a response cost system for verbal outburst.
Give the puppy a treat when he follows his master’s commands.
Marty writes his name in the appropriate space in order to obtain teacher approval.
When students correctly complete their homework assignments, they earn free time using the computer.
Mrs. Hoffman uses differential reinforcement of incompatible behaviors to increase in seat behaviors.

5. Single-Subject Designs
Identifies the effects of variables on a specific behavior of an individual
Require repeated measures of the dependent variable (behavior)
Emphasize clinical rather than statistical significance
Common Components:
Baseline
At least one measure of performance under an intervention
At least one replication of the intervention within the design

6. Baseline Measures Serve 2 Functions: (Kazdin, 1982, 1998)
1) Descriptive Function
2) Predictive Function
How many baseline data points are required?
Typically, at least 5 baseline data points or
Baseline Stability
If no data point of the baseline varies more than 50% from the mean of the baseline.

7. Calculating Baseline Stability
Session Data Points
Step 1: Baseline Mean ( = 71/5 = 14.2)
Step 2: 50% of mean (14 x .50 = 7)
Step 3: Acceptable Range of Data Points ( =) (7, 21)
Step 4: Baseline is stable because no data point varies more than
50% from the mean.

8. Trends
Pattern in the data which indicates a distinct direction in the performance of the behavior
3 data points in the same direction (Barlow & Hersen, 1984)
Increasing trend
(ascending)
Decreasing trend
(descending)

9. AB Design
Baseline
Intervention
Joe

10. AB Design: Advantages and Disadvantages
Simple to use
Cannot be used to make a confident assumption of a functional relation.
Does not provide for replication

11. Reversal Design Referred to as ABAB design
Involves the sequential application and withdrawl of an intervention to verify the intervention’s effects on a behavior
4 Phases of Reversal Design:
1) A: Baseline 1
2) B: Intervention 1
3) A: Baseline 2
4) B: Intervention 2
Demonstration of a functional relation

12. Reversal Design
Baseline
Intervention
Baseline 2
Intervention 2
Meg

13. Reversal Design: Advantages
ABAB design is most desirable of reversal designs because it allows us to see the effects of the independent variable on the natural rate of occurrence of the target behavior
Use this design:
When a clear functional relation between independent and dependent variable needs to be demonstrated
When the nature of the target behavior is such that it can be reversed when the treatment is withdrawn
When the nature of the treatment is such that its effects are not present on the target behavior after it is withdrawn
When withdrawal of treatment does not compromise ethics

14. Reversal Design: Disadvantages
Do not us this design:
When the target behavior is not reversible
When the treatment effects will continue after the treatment with withdrawn
When it is not educationally or clinically desirable for the behavior to return to baseline levels
When the target behavior is such that withdrawal of effective treatment would be unethical

15. Changing Criterion Design
Evaluates the effectiveness of an independent variable by demonstrating that a behavior can be incrementally increased or decreased toward a terminal performance goal
2 Phases:
1) Baseline
2) Intervention
Intervention phase divided into subphases – each requiring a closer approximation to the terminal behavior

16. Changing Criterion Design: Graph
Baseline
Intervention
Joshua

17. Changing Criterion Design: Advantages and Disadvantages
Helpful when working on behaviors that are being shaped
Helpful when the terminal goal that is set takes a long time to reach
The treatment does not have to be withdrawn to show its
requisite functional relation with the target behavior
Not appropriate when the behavior must occur immediately
It may not be appropriate to “hold back” an individual and his/her behavior change

18. Multiple Baseline Design
Allows for simultaneous analysis of more than one dependent variable
Experimentally test the effects of the intervention on:
Two or more behaviors with one student in a single setting (multiple baseline across behaviors)
Two or more students exhibiting the same behavior in a single setting (multiple baseline across students)
Two or more settings in which one student is exhibiting the behavior (multiple baseline across settings)

19. Multiple Baseline Design: Graph
Jim
Percentage of Occurrences
Pete
Jose

20. Multiple Baseline: Advantages
Use this design:
When withdrawal designs are not feasible due to ethical concerns
When there is more than one target behavior, setting, or individual in need of treatment
When the effects of the independent variable cannot be withdrawn or reversed

21. Multiple Baseline: Disadvantage
Do not use this design:
When selected target behaviors are not functionally similar nor independent of one another
If there is only one individual/setting/behavior selected for treatment
When more than on intervention phase is desirable to demonstrate a functional relation
When constraints on resources make implementation impossible

22. Alternating Treatments Design
Allows comparison of the effectiveness of more than one treatment or intervention strategy on a single dependent variable
Scheduling of interventions should be counterbalanced
Fractionation of the data
3 Phases:
1. Baseline
2. Intervention
3. Replication

23. Alternating Treatments Design: Graph
Baseline
Intervention
Replication
Cindy

24. Alternating Treatment Design: Advantages
Use this design:
When you want to determine the relative effectiveness of more than one treatment on a given behavior
When baseline data are either unavailable or might be unstable
When the treatments are sufficiently different from each other
When the subjects can discriminate the treatment conditions
When the effects of sequencing the interventions might obscure the results

25. Alternating Treatment Designs: Disadvantages
Avoid this design:
When the treatments might interact, thus obscuring the results
When the subjects cannot discriminate the treatment conditions
When the treatments typically produce slow behavior changes
When the treatments need to be administered over a continuous period of time to be effective
When it becomes difficult to counterbalance the various aspects of the study

26. Changing Condition Design
Used to investigate two or more interventions on a behavior
Interventions administered sequentially
Variations:
ABC
ABAC
ABACAB

27. Changing Conditions Design: Graph
Baseline
Intervention 1
Baseline
Intervention 2
Nicole

28. Changing Conditions Design: Advantages and Disadvantages
Used to investigate the effect of two or more treatments on the behavior of a student
Cannot be used to determine the effects of a functional relation between the dependent variable and any of the tested independent variables

29. Evaluating Single-Subject Designs
Analysis of Results
Experimental Criterion
Clinical Criterion
Social Validity
Mean of data points within a phase
Levels of Performance Across Phases
Percentage of Overlapping Data Points
Rapidity of Behavior Change

30. Action Research
A systematic inquiry conducted by teachers and other education professions in teaching/learning environments to gather information and reflect upon how their school operates, how they teach, or how well their students learn.
Components of Action Research:
1) identify an area of focus or concern
2) collect data for documentation
3) analyze and interpret data
4) share the information with other and develop an action plan
(Arhar, et al., 2001; Schoen & Nolen, 2004; Stringer, 2004; Mills, 2003)

31. Key Terms
variable enhanced functioning dependent Variable changing criterion design independent variable multiple baseline design baseline data alternating treatment design functional relation changing conditions design trend group designs reversal design single-subject designs ABAB design