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Group Discussion 13. Describe the primary distinction between descriptive research and other research strategies. Describe the three types of survey questions and outline the advantages and disadvantages of each. Single- Subject Research Designs. Chapter 14. Single- subject designs.
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Group Discussion 13 • Describe the primary distinction between descriptive research and other research strategies. • Describe the three types of survey questions and outline the advantages and disadvantages of each.
Single- Subject Research Designs Chapter 14
Single- subject designs 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.
Evaluating the Results from a Single- Subject Study • a single- subject design does not provideresearchers with a set of scores from a group of subjects • Instead, the presentation and interpretation of results from a single- subject experiment are based on visual inspection of a simple graph of the data.
Limitation • The results as presented do not represent a true experiment because there is no control over extraneous variables.
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 types of baseline • Stable level • Stable trend • Unstable data
Dealing With Unstable Data • The researcher can simply wait; occasionally, a participant reacts unpredictably to the novelty of being observed.
Dealing With Unstable Data 2. Consider the average of a set of two ( or more) observations.
Dealing With Unstable Data 3. look for patterns within the inconsistency. For example, a researcher examining disruptive classroom behavior may find that a student exhibits very high levels of disruption on some days and very low levels on other days. days she has a swimming lesson
Length of a Phase • To establish a pattern ( level or trend) within a phase and to determine the stability of the data within a phase, a phase must consist of a minimum of three observations.
When to Change Phases • When the data in a baseline phase show a trend indicating improvement in the client’s behavior, a researcher should not intervene by introducing a treatment phase. • Another possibility is that the baseline data indicate a seriously high level of dangerous or threatening behavior. In this case, a researcher probably should not wait for the full set of five or six observations necessary to establish a clear pattern.
When to stop treatment • If a treatment appears to produce an immediate and severe deterioration in behavior, we should stop the treatment
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 types of change • Change in average level • Immediate change in level • Change in trend • Latency of change.
2- Immediate change in level • Comparing the last point in one phase with the first point in the following phase
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).
Limitations of the ABAB Design • The clinician has implemented a treatment that has corrected a problem behavior, and when the treatment is removed, the correction continues. • A second problem with an ABAB design concerns the ethical question of withdrawing a successful treatment.
2- B not working add C B= Graduated exposure C= Reinforcement
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.
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 students (across subjects)
Person1 Person2 2 different students
Yelling Crying 2 different behaviors
School Home 2 different situations.
Weaknesses of the Multiple- Baseline Design • The risk is that a treatment applied to one behavior may generalize and produce changes in the second behavior. (Treating stuttering may help treating aggressive behavior) • In a multiple- baseline study across behaviors, onebehavior may show a large and immediate change, but the second behavior may show only a minor or gradual change when the treatment is introduced. • The same problem can occur with research involving different participants with similar behavior problems.
4- Dismantling design A dismantling design, also called a component- analysis 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.
5- The Changing- Criterion Design • The criterion level is changed from one phase to the next.
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.
GENERAL STRENGTHS OF SINGLE- SUBJECT DESIGNS • Is conducted with only one participant or occasionally a very small group. • Tends to be much more flexible than a traditional group study. • Single- subject designs require continuous assessment.
General Weaknesses Of Single- Subject Designs • Participant’s behavior may be affectednot only by the treatment conditions but also by the assessment procedures. • Another concern for single- subject designs is the absence of statistical controls.
