Single-subject designs are typically described according to the arrangement of baseline and treatment phases. 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.
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.
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 is a single-subject research design?
Single-subject research designs typically involve measuring the dependent variable repeatedly over time and changing conditions (e.g., from baseline to treatment) when the dependent variable has reached a steady state.
What is the baseline phase of treatment?
A baseline phase is followed by separate phases in which different treatments are introduced. Two or more treatments are alternated relatively quickly on a regular schedule. A baseline is established for several participants and the treatment is then introduced to each participant at a different time.
What does a single subject design measure?
Single-subject research designs typically involve measuring the dependent variable repeatedly over time and changing conditions (e.g., from baseline to treatment) when the dependent variable has reached a steady state.
What is an ABAB single subject design?
A-B-A-B 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).
What is the most common type of analysis in single subject design?
The most basic single-subject research design is the reversal design, also called the ABA design.
What are the basic phases of 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.)
What is ABAB design ABA?
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.
How are the baseline and treatment phase measurements displayed in single subject designs?
Furthermore, the baseline and treatment phase measurements are usually displayed using graphs. Single-subject designs require the repeated measurement of a dependent variable or, in other words, the target problem.
What is pre experimental design?
Pre-experimental designs are research schemes in which a subject or a group is observed after a treatment has been applied, in order to test whether the treatment has the potential to cause change.
What is single system research design?
Single-system designs (SSDs), otherwise known as single-subject, single-case, or N-of-1 designs, are research formats that permit uncontrolled program evaluation and controlled experiments with only one subject, one group, or one system.
Is ABAB a multiple baseline design?
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 are the types of single subject design?
Six primary design types are discussed: the pre-experimental (or AB) design, the withdrawal (or ABA/ABAB) design, the multiple-baseline/multiple-probe design, the changing-criterion design, the multiple-treatment design, and the alternating treatments and adapted alternating treatments designs (see Table 2).
What are the four defining features of single subject experimental designs?
D-3: Identify defining features of single-subject experimental designs (e.g., individuals serve as their own controls, repeated measures, prediction, verification, replication)© Quiz Yourself!
What are the key features of a single-case experimental design?
Single-case experimental designs are a family of experimental designs that are characterized by researcher manipulation of an independent variable and repeated measurement of a dependent variable before (i.e., baseline) and after (i.e., intervention phase) introducing the independent variable.
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 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.
What is the gradual increase or decrease in the dependent variable?
The gradual increases or decreases in the dependent variable across observations. The time it takes for the dependent variable to begin changing after a change in conditions. The percentage of responses in the treatment condition that are more extreme than the most extreme response in a relevant control condition.
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 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.
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…