2. Single Subject Jesus Valdez

3. Purpose To study the changes in behavior of an individual exhibits after exposure to an intervention or treatment of some sort.

4. Essential characteristics Line graphs Dependent outcome is expressed on y-axis Sequence of time is expressed on x- axis Involves extensive collection on subject Can be applied where group designs are difficult

5. 2 ways it differs from other forms of research 1. Baseline is followed by the independent variable 2. Figure caption near the bottom of the graph

6. What is and why baseline What? Graphic record of measurements taken prior to introducing an intervention in a time-series design Why? It’s the control before the treatment

7. The 6 Designs A-B Reversal (A-B-A) A-B-A-B B-A-B A-B-C-B Multiple-baseline

8. A-B Design Design in which measurements are repeatedly made until stability is presumably established (baseline), after which treatment is introduced and an appropriate number or measurements are made

9. A-B-A Design Same as A-B design, except a second baseline is added

10. A-B-A-B Design Same as A-B-A design, except a second treatment is added

11. B-A-B Design Same as A-B-A-B design, except the initial baseline phase is omitted

12. A-B-C-A Design Same as A-B-A design, except a second baseline phase is replaced by a modified treatment phase

13. Multiple-Baseline Design Experimental design in which baseline data are collected on several behaviors for on subject, after which the treatment is applied sequentially over a period of time to each behavior

14. Threats to internal validity Length of the baseline and conditions Number of variables changed form condition to condition Degree and speed of change Return or not of baseline levels Number of baselines

15. Ways to control threat Subject characteristics, mortality, testing, and history Less effective with location, date collector characteristics Weak in instrument decay, data collector bias, attitude

16. External validity Are weak when it comes to generalizability Important to replicate to test generalization

17. Example of Single Subject Onto the Internet