Single subject research design paper
Multiple baseline design example
As Stanovich suggested, research methods serve as the glue that holds together a discipline consisting of many different subdisciplines. Similarly, although clinical psychology was but a faint light on the distant horizon in the early s, it now constitutes the single largest of subdiscipline in the field of psychology. For example, imagine once again that a researcher was examining whether a new treatment reduced SIB in a developmentally disabled child. Although commonly used, the procedure had not yet been effectively evaluated. Then, at a later point, the researcher would introduce the treatment for a second subject, while the third subject continued under baseline. The alternating treatments design can be a quick and effective way of comparing treatments, but only when the treatments are fast acting. Malden, MA: Blackwell. Perone, M.
Thus, after researchers have collected their data using traditional large-N methods, the use of hypothesis testing and inferential statistics allows them to determine whether any difference in group means was due to random, uncontrolled factors or whether the difference was due to the effects of the independent variable.
The researchers concluded that by focusing the functional analysis on precursor conditions, it may be possible to identify the conditions under which the problem behavior is most and least likely to occur. Of course, depending on the purpose of the study, researchers might extend the A-B-A-B design to include more treatment presentations and withdrawals e.
Second, the study is divided into distinct phases, and the participant is tested under one condition per phase.
It is possible that something else changed at around the same time and that this extraneous variable is responsible for the change in the dependent variable.
The nature and history of experimental control.
When should you use single-case and small-n research designs
Malden, MA: Blackwell. Notice that if the researchers had only studied one school or if they had introduced the treatment at the same time at all three schools, then it would be unclear whether the reduction in aggressive behaviours was due to the bullying program or something else that happened at about the same time it was introduced e. One is that if a treatment is working, it may be unethical to remove it. Nevertheless, the rapid expansion of psychology has resulted in the rigorous study of a wide variety of topics that researchers approach from many different theoretical perspectives. Columbus, OH: Merrill. Summary The history of psychology is replete with studies in which early, influential researchers examined interesting phenomena using a small number of subjects under tightly controlled experimental conditions. Of course, depending on the purpose of the study, researchers might extend the A-B-A-B design to include more treatment presentations and withdrawals e. Second, the use of large-N designs may raise practical issues with regard to obtaining research subjects. Journal of Applied Behavior Analysis, 7, For example, we might measure how many baskets someone makes while shooting for 2 minutes. For example, imagine once again that a researcher was examining whether a new treatment reduced SIB in a developmentally disabled child. If the dependent variable is much higher or much lower in one condition than another, this suggests that the treatment had an effect.
In visually inspecting their data, single-subject researchers take several factors into account. In each case, a researcher replicates some aspect of a study as closely as possible and notes the resulting outcomes. Specifically, inferential statistics provided researchers with a quantitative means of determining whether their groups were meaningfully different.
This approach allows the researcher to see whether changes in the independent variable are causing changes in the dependent variable. Influenced by the early statistical work of Sir Ronald A.
Single case methodology
The multiple baselines can be for different participants, dependent variables, or settings. In essence, multiple-baseline designs entail the measurement of behavior under more than one baseline condition and the staggered introduction of a treatment to see if behavior changes only when the treatment is introduced. In the large majority of studies conducted in psychology e. Thus, after researchers have collected their data using traditional large-N methods, the use of hypothesis testing and inferential statistics allows them to determine whether any difference in group means was due to random, uncontrolled factors or whether the difference was due to the effects of the independent variable. After 2 more weeks, they implemented it at the second school. We might play music while shooting, give encouragement while shooting, or video the person while shooting to see if our intervention influenced the number of shots made. Twelve subjects with prior stroke were recruited; 11 completed the study. Specifically, I will discuss a the history of single-subject designs in psychology, b problems with large-N designs and why single-subject designs have regained some popularity in the past 30 to 40 years, c characteristics shared by different single-subject designs, and d some of the most common single-subject designs. Myerson, J.
In fact, psychology has exploded to such an extent in the last 50 years that some psychologists would argue that now it consists of nothing more than a large number of disjointed subareas, many of which have little relation to one another e. Hall et al.
An added benefit of this design, and all single-case designs, is the immediacy of the data.
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