The conditions in a single-subject experimental study are often assigned letters such as the A phase and the B phase, with A being the baseline, or no-treatment phase, and B the experimental, or treatment phase. (Other letters are sometimes used to designate other experimental phases.)
Full Answer
What are the phases of a single subject design?
The most basic single-subject research design in which the researcher measures the dependent variable in three phases: Baseline, before a treatment is introduced (A); after the treatment is introduced (B); and then a return to baseline after removing the treatment (A). It is often called an ABA design. Another term for reversal design.
Why do we use single-subject designs in clinical trials?
Also with the disorders that we deal with, it’s very hard to get the number of participants that we would need for the gold standard randomized controlled trial. Using single-subject designs works around the possible limiting factor of not having enough subjects in a particular area of study.
Is single subject design a crucial methodology among several?
So I see it as a crucial methodology among several. What we can do to promote what single-subject design is good for is to speak up. It is important that it is being recognized for what it can do and what it cannot do.
How is the outcome variable measured in single subject designs?
The outcome variable is measured repeatedly within and across different conditions or levels of the independent variable. Single-subject designs are typically described according to the arrangement of baseline and treatment phases.
What are the phases of a single-subject design?
The conditions in a single-subject experimental study are often assigned letters such as the A phase and the B phase, with A being the baseline, or no-treatment phase, and B the experimental, or treatment phase. (Other letters are sometimes used to designate other experimental phases.)
Is ABAB a single-subject design?
The most basic single-subject research design is the reversal design , also called the ABA design. During the first phase, A, a baseline is established for the dependent variable. This is the level of responding before any treatment is introduced, and therefore the baseline phase is a kind of control condition.
What does B stand for in ABAB design?
The A-B-A-B design represents an attempt to measure a baseline (the first A), a treatment measurement (the first B), the withdrawal of treatment (the second A), and the re-introduction of treatment (the second B).
Is ABAB multiple baseline?
In the ABAB design the two demonstartions are the first and second time the phase changes from baseline to treatment and in the multiple-baseline design it is after the first participants/behavior/setting and then again for the second particpant/behavior/setting.
What is ABAB model?
An ABAB research design, also called a withdrawal or reversal design, is used to determine if an intervention is effective in changing the behavior of a participant. The design has four phases denoted by A1, B1, A2, and B2. In each phase, repeated measurements of the participant's behavior are obtained.
Why would we use an ABA versus an ABAB design?
The ABA design can help find effective treatment methods and models. The ABAB method reintroduces the intervention to help end on a positive note as the therapy is brought back.
What is a multielement design?
A multielement design is also known as an alternating treatments design, because it measures the effect of multiple treatments delivered one after the other. For instance, two treatments may be compared in order to see which is most efficient in producing the target behavior.
What is the reversal phase of an ABAB study?
An ABAB reversal involves two conditions wherein 'A' is a baseline or no-intervention (or no manipulation) condition and 'B' is an intervention condition. Observations of a specified length (e.g., 15 min) are first conducted under the baseline condition.
Why is an AB design non experimental?
Although the AB design is often described as a SSED, it is more accurately considered a pre-experimental design because it does not sufficiently control for many threats to internal validity and, therefore, does not demonstrate experimental control.
What kind of design is an ABAB design?
Withdrawal designs, also known as ABAB designs, rely on the comparisons between conditions when an intervention is in place and conditions when that intervention is not being implemented. This comparison demonstrates the impact of the IV on the DV (Ledford & Gast, 2018 p. 217).
Why is ABAB design typically superior to AB design?
Why is an ABAB design superior to an ABA design? The ABAB design is superior to the ABA design because a single reversal is not strong enough for the effectiveness of the treatment. Also the sequence ends with the treatment rather than with people withdrawing from the treatment.
What is the fifth guideline when using ABAB design?
The fifth requirement concerns those extraneous factors that might be associated with , or at least present during, the intervention condition and are not shared with the control condition.
What is single subject therapy?
Although researchers have used single-subjects designs with less positivist therapies, such as narrative therapy , the single-subjects design is generally used in therapies with more quantifiable outcomes . The results of single-subjects studies are not generalizable to the overall population, but they help ensure that social workers are not ...
Why do social workers use single subject designs?
Because clinical social work often involves one-on-one practice, single-subjects designs are often used by social workers to ensure that their interventions are having a positive effect. While the results will not be generalizable, they do provide important insight into the effectiveness of clinical interventions.
What is baseline stage?
The baseline stage is the period of time before the intervention starts. During the baseline stage, the social worker is collecting data about the problem the treatment is hoping to address. For example, a person with substance use issues may binge drink on the weekends but cut down their drinking during the work week.
What is the importance of single subject research?
Another important aspect of single-subject research is that the change from one condition to the next does not usually occur after a fixed amount of time or number of observations. Instead, it depends on the participant’s behaviour.
How does single subject research differ from group research?
In addition to its focus on individual participants, single-subject research differs from group research in the way the data are typically analyzed. As we have seen throughout the book, group research involves combining data across participants. Group data are described using statistics such as means, standard deviations, Pearson’s r, and so on to detect general patterns. Finally, inferential statistics are used to help decide whether the result for the sample is likely to generalize to the population. Single-subject research, by contrast, relies heavily on a very different approach called#N#visual inspection#N#. This means plotting individual participants’ data as shown throughout this chapter, looking carefully at those data, and making judgments about whether and to what extent the independent variable had an effect on the dependent variable. Inferential statistics are typically not used.
What is a reversal design?
The most basic single-subject research design is the#N#reversal design#N#, also called the ABA design. During the first phase, A, a is established for the dependent variable. This is the level of responding before any treatment is introduced, and therefore the baseline phase is a kind of control condition. When steady state responding is reached, phase B begins as the researcher introduces the treatment. There may be a period of adjustment to the treatment during which the behaviour of interest becomes more variable and begins to increase or decrease. Again, the researcher waits until that dependent variable reaches a steady state so that it is clear whether and how much it has changed. Finally, the researcher removes the treatment and again waits until the dependent variable reaches a steady state. This basic reversal design can also be extended with the reintroduction of the treatment (ABAB), another return to baseline (ABABA), and so on.
Can single subject research be analyzed?
The results of single-subject research can also be analyzed using statistical procedures— and this is becoming more common. There are many different approaches, and single-subject researchers continue to debate which are the most useful. One approach parallels what is typically done in group research.
Is it unethical to remove a treatment?
One is that if a treatment is working, it may be unethical to remove it. For example, if a treatment seemed to reduce the incidence of self-injury in a developmentally disabled child, it would be unethical to remove that treatment just to show that the incidence of self-injury increases.
What is the importance of single subject research?
Another important aspect of single-subject research is that the change from one condition to the next does not usually occur after a fixed amount of time or number of observations. Instead, it depends on the participant’s behavior. Specifically, the researcher waits until the participant’s behavior in one condition becomes fairly consistent ...
How does single subject research differ from group research?
In addition to its focus on individual participants, single-subject research differs from group research in the way the data are typically analyzed. As we have seen throughout the book, group research involves combining data across participants. Group data are described using statistics such as means, standard deviations, correlation coefficients, and so on to detect general patterns. Finally, inferential statistics are used to help decide whether the result for the sample is likely to generalize to the population. Single-subject research, by contrast, relies heavily on a very different approach called#N#visual inspection#N#. This means plotting individual participants’ data as shown throughout this chapter, looking carefully at those data, and making judgments about whether and to what extent the independent variable had an effect on the dependent variable. Inferential statistics are typically not used.
What is a reversal design?
During the first phase, A, a is established for the dependent variable. This is the level of responding before any treatment is introduced, and therefore the baseline phase is a kind of control condition. When steady state responding is reached, phase B begins as the researcher introduces the treatment. There may be a period of adjustment to the treatment during which the behavior of interest becomes more variable and begins to increase or decrease. Again, the researcher waits until that dependent variable reaches a steady state so that it is clear whether and how much it has changed. Finally, the researcher removes the treatment and again waits until the dependent variable reaches a steady state. This basic reversal design can also be extended with the reintroduction of the treatment (ABAB), another return to baseline (ABABA), and so on.
Can single subject research be analyzed?
The results of single-subject research can also be analyzed using statistical procedures— and this is becoming more common. There are many different approaches, and single-subject researchers continue to debate which are the most useful. One approach parallels what is typically done in group research.
Is it unethical to remove a treatment?
One is that if a treatment is working, it may be unethical to remove it. For example, if a treatment seemed to reduce the incidence of self-injury in a child with an intellectual delay, it would be unethical to remove that treatment just to show that the incidence of self-injury increases.
What is single subject design?
Single Subject Designs are used not just for research but also to "evaluate practice" and improve client outcomes through monitoring a client's progress. At a minimum, single-subject research designs include: *repeated measurements - identifies client's status.
What is preferred method?
The "preferred method" is to take measures of the target with the client prior to implementing the intervention For example, during the assessment process and during the course of the intervention. identifies client's status.
What is stable line?
stable line: a line that is relatively flat with little variability (easier to rule out) trend line: an ascending or descending line (difficult to rule out) cycle: a pattern reflecting ups and downs depending on time of measurement.
What is simultaneous treatment?
The same is true for simultaneous-treatment designs; a design that is appropriate for situations where one wishes to evaluate the concurrent or simultaneous application of two or more treatments in a single case. Rapid or random alteration of treatment is not required with simultaneous-treatment design.
How to implement alternating treatment?
To implement an alternating treatments design, begin as usual with a brief baseline, simply to ensure that the client actually needs intervention to eat those foods. You then alternate meals back and forth between the two different treatments that you want to evaluate.
How many alterations are required for ATD?
ATD requires a minimum of two alterations per data series.
What is an ATD?
The alternating treatment design (ATD) consists of rapid and random or semirandom alteration of two or more conditions such that each has an approximately equal probability of being present during each measurement opportunity. As an example, it was observed during a clinical training case that a student therapist, during many sessions, would alternate between two conditions: leaning away from the client and becoming cold and predictable when he was uncomfortable, and leaning towards the client and becoming warm and open when feeling comfortable. The client would disclose less when the therapist leaned away, and more when he leaned forward. If it were assumed that the therapist had preplanned the within-session alternations, an ATD as shown in Figure 6 would be obtained. The condition present in the example at any given time of measurement is rapidly alternating. No phase exists; however, if the data in each respective treatment condition are examined separately, the relative level and trend of each condition can be compared between the two data series (hence the name between-series designs).
What is Snyder and Shaw's methodology?
Snyder & Shaw (this volume) provide a substantive discussion of the use of single-case experimental designs (also referred to as “small-n designs”) to answer an assortment of questions about sexuality. Nonetheless, we believe that the use of single-case experimental methodology to answer questions regarding childhood sexuality is of sufficient importance to warrant some discussion here.
What is single case design?
Although usually labeled a quasi-experimental time-series design, single-case research designs are described in this article as a separate form of research design (formerly termed single-subject or N = 1 research) that have a long and influential history in psychology and education (e.g., Kratochwill, 1978; Levin et al., 2003) and can serve as an alternative to using large, aggregate group designs ( Shadish and Rindskopf, 2007 ). Single-case research designs bear similarly to time-series design and have often been regarded as quasi-experimental because they usually do not (but could) include randomization in the experiment. In the single-case design, replication is scheduled to help rule out various threats to validity. Single-case designs can involve a single participant or group as the unit but differ from repeated measures and hierarchical linear modeling (HLM) designs because multiple observations are taken over a long period of time within a design structure of replication and/or randomization of the conditions of the experiment.
When to use ATDs?
ATDs are ideally used with behaviors emitted at a relatively high frequency that correspondingly allows many instances of each alternate intervention to be applied. However, the design may be used with relatively infrequent behaviors if data is collected for a longer period of time.
General Features of Single-Subject Designs
Reversal Designs
- The most basic single-subject research design is the , also called the . During the first phase, A, a is established for the dependent variable. This is the level of responding before any treatment is introduced, and therefore the baseline phase is a kind of control condition. When steady state responding is reached, phase B begins as the researche...
Multiple-Baseline Designs
- There are two potential problems with the reversal design—both of which have to do with the removal of the treatment. One is that if a treatment is working, it may be unethical to remove it. For example, if a treatment seemed to reduce the incidence of self-injury in a child with an intellectual delay, it would be unethical to remove that treatment just to show that the incidence …
Data Analysis in Single-Subject Research
- In addition to its focus on individual participants, single-subject research differs from group research in the way the data are typically analyzed. As we have seen throughout the book, group research involves combining data across participants. Group data are described using statistics such as means, standard deviations, correlation coefficients, and so on to detect general pattern…