How does the alternative-treatments design differ from the changing-criterion, withdrawal, and multiple-baseline designs?
The alternative-treatments design (ATD) entails the systematic interchanging of two or more interventions over time and contrasting the responses of each variable to the intervention. ATD permits participants to be subjected to specific treatment conditions for equal durations. Therefore, ATD is delineated as a between-series plan given that it likens outcomes from two or more distinct progressions of data points.
It is possible to alternate treatments for short durations by offsetting or allocating treatments arbitrarily in various stages of the study. Consequently, different treatments and their upshots can be likened over time, thereby expanding the literature base on evidence-based practice.
As opposed to changing criterion, multiple-baseline, and withdrawal designs, ATD makes it possible to ascertain late treatment outcomes continuous baselines can be used as a basis for comparison. Additionally, the ongoing baselines facilitate the testing of variables that often happen at unstable rates. Another difference between ATD and other designs is that a baseline is not a prerequisite for testing. Nevertheless, if a baseline is required, it does not need to be lengthy, which is more practical and ethically helpful. A difference between ATD and withdrawal design is that the former design eliminates the ethical dilemma of withdrawing treatment.
Discuss the major tenets of the simultaneous-treatments design
The key tenets of simultaneous-treatments design (STDs) include the presentation of at least two treatments at the same time in each case. STDs normally evaluate the predilections of participants among a group of treatments. When executing STDs, there is unequal exposure of subjects to various treatments due to the forcing of choices except in instances where the patient has equal inclinations to the interventions.
Explain the limitations of the alternating-treatments design
The main limitation of the ATD is difficulty establishing cause and effect due to causal inferences regarding the efficacy of intermediations. Such difficulties are attributed to multiple-treatment interference, which threatens the internal validity of the design because of interactions between the present and future treatments. This shortcoming can be circumvented by making the treatment conditions random or counterbalancing across subjects.
Discuss multi-treatment interference and outline (with examples) how its effects can be minimized in the alternating-treatments design
Multi-treatment interference (MTI) denotes the influence of one treatment on another. For instance, when a subject experiences more than one treatment, coming into contact with one intervention may alter the effectiveness of subsequent remedies. MTI may occur in all situations, including the prior history of participants (baseline and lack of previous experience). Comparing treatments within-subjects may yield four likely as a result of MTI.
Exposure to other interventions may potentiate or reduce the subsequent treatments, the effect of one treatment may be increased by the baseline conditions, or the treatments may not affect each other (Barker et al., 2011). Sequence effects may be minimized by interspersing treatment implementation quickly. Additionally, interventions can be applied for shorter times to prevent the formation of a learning history that could affect subsequent treatments.
Sequence effects can also be avoided by the arbitrary ordering of treatments in the intervention phase. ‘Carry-over’ effects are MTIs where the inherent features of treatment affect subsequent interventions and not the order of administration. This limitation can be overcome by balancing the sequence of the treatments, for instance, using specified time intervals (such as one week) between treatments and giving slower and distinct treatment modifications.
Discuss the major trends of the alternating-treatments design
The ATD design comes from a collection of experimental designs that are prevalent in the investigation of operant behavior in applied situations. These have been used to pinpoint associations between behavior and impetus in learning experiments. However, the application of ATD in sports and exercise is limited.
Nonetheless, in the sports and exercise realm, there is evidence to show the use of ATD in the evaluation of on-task conduct, correct practice trials, and overall practice attempts under diverse supervision configurations (Barker et al., 2011). ATD has also been used to contrast the effects of various treatments in enhancing the percent precision of setting in volleyball. The design has also been applied in the comparison of various effects of conventional coaching as a baseline condition with normal coaching and public self-regulation.
Barker, J., McCarthy, P., Jones, M., & Moran, A. (2011). Single case research methods in sport and exercise. Routledge.