Single -Subject Designs - Ch 5

1. Single -Subject Designs - Ch 5 “Data collection allows teachers to make statements about the direction and magnitude of behavioral changes” (p. 116). In short, teachers can verify that their instruction/intervention is working based on data. AT5.ppt

2. Big Idea: An array of ABA designs exists • Certain ABA designs (a.k.a. formats) can indicate experimentally to others ‘what is working’ in your classroom for your students. • Of all 6 designs, 3 do yield functional relationships(ABAB, Changing Criterion, and Multiple Baseline) • Of all 6 designs, 3 do not yield functional relationships (AB, Changing Conditions, and Alternating Treatment) • See glossary - p.425 for definition of functional relationship • See page 118 (‘Single-subject experimental designs allow…cause of the effects’) for explanation of functional relationships. AT5.ppt

3. Preface: The social sciences use two methods to test hypotheses. • Group designs compare the performance of one sample of individuals (e.g., people who don’t smoke, or rabbits who don’t have smoke blown into their cages) with another (e.g., people who do smoke, or rabbits who do have smoke blown into their cages). • Single-subject designs compare the performance of an individual* before and after a specified intervention. • Read pages 119-20 (‘Applied behavior analysis...they will work.’) • *Note: Sometimes single-subject design procedures are applied to groups (e.g., designated driver or graffiti studies). AT5.ppt

4. ABA - Baseline Requirements“Baseline data are measures of the level of behavior (the dependent variable) as it occurs naturally, before intervention.” • In order to evaluate whether your instruction is achieving changes in your students’ school life, you should begin with a baseline. • Baseline data are measures of the level of behavior (recall the description of dependent variables) as it occurs naturally (prior to your intervention). • Certain rules govern the collection of valid baeline data. AT5.ppt

5. ABA - Baseline Rules • General Assumption: Baseline will have at least 5 data points. • Stability of the baseline must be demonstrated • Stability is based on whether the baseline data represent the group or vary a lot – highs and lows but no real average group. Stability has also been called “variability.” • How the baseline data are trended - ascending or descending - is also important. AT5.ppt

6. ABA - Baseline Requirements When baselines are unstable (variable), the first thing to examine is the definition of the target behavior. A lack of stability in the baseline may suggest the operational definition of the target behavior is not sufficiently descriptiveto allow for accurate and consistent recording or that the data collector is not being consistentin the procedure used for data collection (p. 120). AT5.ppt

7. ABA - Baseline Requirements Example: # correct (16, 5, 9, 11, 10, 9) • Find the mean (average) 60/6 = 10 • Divide the mean in half = 5 • Add & subtract B from the mean = 5 and 15 • Determine if all baseline data fall between the high & low range in C. No. Stability is based on whether the data vary a lot. This has been termed “variability” and “stability.” Here’s how you determine this facet of baseline stability. WordsCorrect AT5.ppt

8. ABA - Baseline Requirements Stability is also based on how the data are trended - ascending or descending. “…3 successive data points in the same direction” (p. 121). Examples: If this chart is a picture of # correct on a spelling test, we can say that the data are appropriately trended. That is they are going in the opposite direction of what we seek - increasing spelling performance. If this chart is a picture of # tattles on the playground, we can say that the data are not appropriately trended. That is, they are going in the direction of what we seek - decreasing tattling. Words Correct AT5.ppt

9. ABA - Baseline Requirements Stability is also based on how the data are trended - ascending or descending. “…3 successive data points in the same direction” (p. 121). Examples: If this chart is a picture of # correct on a spelling test, we can say that the data are appropriately trended. That is they are going in the opposite direction of what we seek - increasing spelling performance. If this chart is a picture of # tattles on the playground, we can say that the data are not appropriately trended. That is, they are going in the direction of what we seek - decreasing tattling. TattlingEvents AT5.ppt

10. Single Subject Designs AB (a.k.a. “teacher”) Design Some Considerations • Simplicity • Cannot be used to establish functional relationship • Very vulnerable to confounding variables or coincidental events • See example on next slide. AT5.ppt

11. Single Subject Designs 1.AB (a.k.a. “teacher”) Design Example: Spelling test performance for Jo-Jo A B Note: Teacher cannot confirm that intervention produced the successful results. Words Correct AT5.ppt

12. Single Subject Designs 2.ABAB (a.k.a. “reversal”) Design • Some Considerations • +Simplicity • +Functional relationship is established • -Takes longer • -Necessity of withdrawing an effective intervention • -Not appropriate with dangerous behaviors • Could appear as a BAB if behavior did not intitially exist in subject’s repertoire • See example on next slide. AT5.ppt

13. Single Subject Designs ABAB (a.k.a. “reversal”) Design Example: Spelling test performance for Jo-Jo Note: Teacher can confirm that intervention produced the successful results. A B A B Words Correct AT5.ppt

14. Single Subject Designs 3.Changing Criterion Design • Some Considerations • +Gradual acquisition may not be appropriate here • +Functional relationship is established (w. 3 successful phases) • +Continually progresses toward target behavior - no reversal • +Appropriate in ‘shaping’ behaviors • Requires setting interim and final goals “After the student has reached the established level of performance in a predetermined number of consecutive sessions (usually 2, or in 2 out of three consecutive sessions of a subphase), the level of performance required for reinforcement should be adjusted in the direction of the desired level…Each successive interim level of performance should be determined using the same mathematical difference established at the first interim level of performance” (p. 131). OYO Read 4 strategies on page 131. AT5.ppt

15. Single Subject Designs Changing Criterion Design Example: Spelling test performance for Jo-Jo Note: Teacher can confirm that intervention produced the successful results (w. 3 successful phases). A B1 B2 B3 AT5.ppt

16. Single Subject Designs 4.Multiple Baseline Design • Some Considerations • +Functional relationship is established w/o withdrawing intervention - this is based on continuous data collection of baseline • -Not appropriate when intervention is needed immediately • Subsequent interventions are based on • 3 data points trended appropriately • Predetermined criteria (e.g., 4 of 5 appropriately trended points) • Second, third, etc. introductions of the intervention yielding results constitutes replication • See example on next slide. AT5.ppt

17. Single Subject Designs Multiple Baseline Design Example: Spelling test performance for Jo-Jo & D-D B A Note: Teacher can confirm that intervention produced the successful results A B AT5.ppt

18. Single Subject Designs 5.Alternating Treatment Design(a.k.a. multiple schedule, alternating conditions, multiple element) • Some Considerations • To fairly compare 2 (or more) interventions, counterbalance administrations • Specify which intervention you are implementing “Now we are going to use the CAI, not the TDI intervention • Applying the more effective intervention to the content can affirm that the more effective intervention works better • Extending the effective intervention into an ABAB study can produce a functional relationship • Allows teachers to make decisions about “what works” in classrooms • Use Wilson et. al (1996) example on p. 111 for further explanation. • See example on next slide. AT5.ppt

19. Single Subject Designs Alternating Treatment Design Example: Spelling test performance for Jo-Jo Note: Teacher cannot confirm that an intervention produced the successful results. Teacher Presented A B Computer Presented AT5.ppt

20. Single Subject Designs 6.Changing Conditions Design(a.k.a. ABC) • Some Considerations • Used to compare 2 (or more) interventions • +Helpful in deciding what will work for a specific student after Functional Behavioral Analysis • -No functional relationship occurs as a result • May include a return to baseline between each condition (AB AC AD) • See example on next slide. AT5.ppt

21. Single Subject Designs Changing Conditions Design Example: Spelling test performance for Jo-Jo A B C Note: Teacher cannot confirm that an intervention produced the successful results. Earns Candy Earns Money AT5.ppt

22. How are results evaluated? • Successfully repeating the intervention with a subject adds credibility • Changes that produce “meaningful” results are valued • Visually inspecting the data provides the best evidence of effectiveness • Change in means • Levels of performance • Trends in performance AT5.ppt

23. How are results evaluated? • Change in means - difference between baseline mean and intervention mean(s): Baseline mean = 8.16 Intervention mean = 13.5 Change in means = 5.34 • 13.50 • 8.16 • 5.34 AT5.ppt

24. How are results evaluated? • Level of performance - difference between last baseline data point and first intervention data point: Last baseline data point = 5 First intervention data point = 12 Level of performance difference = +7 AT5.ppt

25. How are results evaluated? • Trend in performance - focuses on systematic and consistent increases or decreases in intervention performance Average of first half of intervention data points = 13 Average of second half of intervention data points = 14.3 Connect the points and determine if line ascends, descends, remains unchanged. AT5.ppt