QUANTITATIVE RESEARCHMETHODOLOGIES SINGLE-SUBJECT RESEARCH
ESSENTIAL CHARACTERISTICSData are collected and analyzed for only one subject at one time.Most commonly used to study the changes in behavior
THE GRAPHING OF SINGLE-SUBJECT DESIGNSResearchers primarily use line graphs to; Present their data Illustrate the effects of a particular intervention or treatment.
THE A-B DESIGN Collecting data on the same subject, operating as his or her own control under two conditions or phases. First condition (A); pretreatment condition Second condition (B); treatment or intervention condition, introduced and maintained for a period of time. figure 14.2 A-B Design.jpg
DISADVANTAGE OF A-B DESIGNResearcher does not know whether any behavior change occurred because of the treatment.
THE A-B-A DESIGN Sometimes called reversal design Researchers simply add another baseline period To get stronger evidence for the effectiveness of the intervention Reduce threats to internal validity figure 14.3 A-B-A Design.jpg
DISADVANTAGE OF A-B-A DESIGNItinvolves leaving the subjects in the A condition.Studiesended without some degree of final improvement.
THE A-B-A-B DESIGN Two baseline periods are combined with two treatment periods. Permits the effectiveness of the treatment. Avoids leaving subject without an intervention. Demonstrate that dependent variable changes as independent variable is applied. figure 14.4 A-B-A-B Design.jpg
DISADVANTAGES OF A-B-A-B DESIGNThe possibility of data-collector biasAn instrumentation effect; need for an extensive number of data collections period
THE B-A-B DESIGN Involvesa treatment followed by a baseline by a return to the treatment. Appropriate when there is a lack of behavior. figure 14.5 B-A-B Design.jpg
THE A-B-C-B DESIGN Further modification of the A-B-A design. The intervention is changed to control for any extra attention the subject may have received. Contingent(or selective) praise is critical for improved responsiveness. figure 14.6 A-B-C-B Design.jpg
MULTIPLE-BASELINE DESIGNS Researcher do more than collect data on one behavior. They collect on several behaviors for one subject. Researchers systematically apply the treatment at different time for each behavior. figure 14.8 Multiple-Baseline Design.jpg Treatment is applied to change behaviors accordingly.
THREATS TO INTERNAL VALIDITY1. Condition length2. Number of variables changed when moving from one condition to another.3. Degree and speed of change.4. Return to baseline level5. Independence of behavior6. Number of baseline
THINGS TO PONDER Whichdo you think is easier to conduct: single subject or group comparison research? Why? What sorts of behaviors might require only a few data points to establish a baseline?