Threats to Internal Validity in Multiple-Baseline Design Variations.

Multiple baseline designs-both concurrent and nonconcurrent-are the predominant experimental design in modern applied behavior analytic research and are increasingly employed in other disciplines. In the past, there was significant controversy regarding the relative rigor of concurrent and nonconcurrent multiple baseline designs. The consensus in recent textbooks and methodological papers is that nonconcurrent designs are less rigorous than concurrent designs because of their presumed limited ability to address the threat of coincidental events (i.e., history). This skepticism of nonconcurrent designs stems from an emphasis on the importance of across-tier comparisons and relatively low importance placed on replicated within-tier comparisons for addressing threats to internal validity and establishing experimental control. In this article, we argue that the primary reliance on across-tier comparisons and the resulting deprecation of nonconcurrent designs are not well-justified. In this article, we first define multiple baseline designs, describe common threats to internal validity, and delineate the two bases for controlling these threats. Second, we briefly summarize historical methodological writing and current textbook treatment of these designs. Third, we explore how concurrent and nonconcurrent multiple baselines address each of the main threats to internal validity. Finally, we make recommendations for more rigorous use, reporting, and evaluation of multiple baseline designs.

Revisiting an Analysis of Threats to Internal Validity in Multiple Baseline Designs.

In our previous article on threats to internal validity of multiple baseline design variations (Slocum et al., 2022), we argued that nonconcurrent multiple baseline designs (NCMB) are capable of rigorously demonstrating experimental control and should be considered equivalent to concurrent multiple baselines (CMB) in terms of internal validity. We were fortunate to receive five excellent commentaries on our article from experts in single-subject research design-four of whom endorsed the conclusion that NCMBs should be considered strong experimental designs capable of demonstrating experimental control. In the current article, we address the most salient points made in the five commentaries by further elaborating and clarifying the logic described in our original article. We address arguments related to classic threats including maturation, testing and session experience, and coincidental events (history). We rebut the notion that although NCMBs are strong, CMBs provide an increment of additional control and discuss the application of probability-based analysis of the likelihood of threats to internal validity. We conclude by emphasizing our agreement with many of the commentaries that selection of single-case experimental designs should be based on the myriad subtleties of research priorities and contextual factors rather than on a decontextualized hierarchy of designs.

Ethical Behavior Analysis: Evidence-Based Practice as a Framework for Ethical Decision Making.

As the number of applied behavior analysts continues to grow, ethical practice and decision making become increasingly important. Specifically, improving behavior analysts' ethical decision-making repertoires is critical to effective and ethical behavioral service delivery within the field of applied behavior analysis (ABA). This article proposes that the evidence-based practice (EBP) of ABA (Slocum et al., 2014) provides a framework to support fluent ethical decision making. The purpose of this article is to (a) review the importance of ethical decision making related to the practice of ABA, (b) introduce and summarize EBP of ABA, (c) review the three main components of EBP of ABA, and (d) discuss the broader role that EBP of ABA can play in the field of ABA. We tie the EBP of ABA to current Behavior Analyst Certification Board ethical standards and present actions that behavior analysts can engage in to support their ethical decision making throughout.

Features of Direct Instruction: Content Analysis.

The goal of Direct Instruction (DI) is to teach content as effectively and efficiently as possible. To do this, instructional designers must identify generative relations or strategies that allow the learner to respond correctly to untaught situations. The purpose of content analysis is to identify generative relations in the domain to be taught and arrange the content in such a way that it supports maximally generative instruction. This article explains the role of content analysis in developing DI programs and provides examples and nonexamples of content analysis in five content domains: spelling, basic arithmetic facts, earth science, basic language, and narrative language. It includes a brief sketch of a general methods of conducting a content analysis. It concludes that content analysis is the foundation upon which generative instruction is built and that instructional designers could produce more effective, efficient, and powerful programs by attending explicitly and carefully to content analysis.

Features of Direct Instruction: Interactive Lessons.

Direct Instruction (DI) teaches challenging academic content to a range of diverse learners. In order to do so, DI includes a complex system for organizing and directing teacher-student interactions to maximize learning. This system includes: instructional formats that specify the interactions between teacher and student, flexible skills-based groupings, active student responding, responsive interactions between students and teachers, ongoing data-based decision making, and mastery teaching. In this article, we describe each of these main features of the system, define their functions, reveal how they are interwoven throughout all DI lessons, and provide specific examples of their application during instruction. Our goal is to describe and clarify critical features of DI lesson presentation and teacher-student interaction so that instructional designers, teachers, and other practitioners can use existing DI programs effectively and include these features in newly developed programs.

Which Exercise Interventions Can Most Effectively Improve Reactive Balance in Older Adults? A Systematic Review and Network Meta-Analysis.

BACKGROUND: Reactive balance is the last line of defense to prevent a fall when the body loses stability, and beneficial effects of various exercise-based interventions on reactive balance in older adults have been reported. However, their pooled evidence on the relative effects has yet to be described. OBJECTIVE: To review and evaluate the comparative effectiveness of various exercise-based interventions on reactive balance in older adults. METHODS: Nine electronic databases and reference lists were searched from inception to August 2021. Eligibility criteria according to PICOS criteria were as follows: (1) population: older adults with the mean age of 65 years or above; (2) intervention and comparison: at least two distinct exercise interventions or one exercise intervention with a no-exercise controlled intervention (NE) compared in each trial; (3) outcome: at least one measure of reactive balance; (4) study: randomized controlled trial. The main network meta-analysis was performed on data from the entire older adult population, involving all clinical conditions as well as healthy older adults. Subgroup analyses stratified by characteristics of participants (healthy only) and reactive balance outcomes (simulated slip or trip while walking, simulated forward falls, being pushed or pulled, and movable platform) were also conducted. RESULTS: Thirty-nine RCTs (n = 1388) investigating 17 different types of exercise interventions were included in the network meta-analysis. Reactive balance training as a single intervention presented the highest probability (surface under the cumulative ranking (SUCRA) score) of being the best intervention for improving reactive balance and the greatest relative effects vs. NE in the entire sample involving all clinical conditions [SUCRA = 0.9; mean difference (95% Credible Interval): 2.7 (1.0 to 4.3)]. The results were not affected by characteristics of participants (i.e., healthy older adults only) or reactive balance outcomes. SUMMARY/CONCLUSION: The findings from the NMA suggest that a task-specific reactive balance exercise could be the optimal intervention for improving reactive balance in older adults, and power training can be considered as a secondary training exercise.

A Dynamic Measure of Morphological Awareness and First-Grade Literacy Skill.

Purpose The purpose of this feasibility study was to investigate an early dynamic measure of morphological awareness (MA) involving graduated prompts to measure early MA skill and determine whether this task relates to and predicts performance on other language and/or literacy measures in first-grade children with language abilities typically found in the classroom. Method In addition to a battery of language and literacy measures, a dynamic assessment of MA was designed and administered to 74 first-grade children with a range of language abilities. Results The dynamic measure of MA was found to be valid, reliable, and measured early school-age MA performance for children with typical language and those at risk for developmental language disorder. For children with typical language, the developed dynamic MA measure was related to and predictive of performance on other language and literacy measures above and beyond static phonological and MA measures. Conclusions The results provide preliminary support for the use of dynamic assessment to measure MA in first-grade children with a range of language abilities. Supplemental Material https://doi.org/10.23641/asha.12591767.

Language preference and reinforcing efficacy of praise in bilingual children with disabilities.

We conducted a stimulus preference assessment to identify preference for praise delivered in English versus Spanish for bilingual students. Next, a concurrent-operant reinforcer assessment was used to evaluate the reinforcer efficacy of praise in each language. Participants showed limited to no preference for one language over another. One participant showed a slight preference for Spanish praise and Spanish praise functioned as a slightly more potent reinforcer. If a participant did not prefer a specific language of praise (i.e., undifferentiated preference or equal percentage of approaches), both languages were considered to be similarly reinforcing.

Manipulating parameters of reinforcement to reduce problem behavior without extinction.

Differential reinforcement of alternative behavior (DRA) most often includes extinction as a treatment component. However, extinction is not always feasible and it can be counter-therapeutic if implemented without optimal treatment integrity. Researchers have successfully implemented DRA without extinction by manipulating various parameters of reinforcement such that alternative behavior is favored. We extended previous research by assessing three participants' sensitivities to quality, magnitude, and immediacy using arbitrary responses and reinforcers that maintain problem behavior. The results were used to implement an intervention for problem behavior using DRA without extinction. Our findings indicate that arbitrary responses can be used to identify individual and relative sensitivity to parameters of reinforcement for reinforcers that maintain problem behavior. Treatment was effective for all participants when we manipulated parameters of reinforcement to which they were most sensitive, and, for two participants, the treatment was less effective when we manipulated parameters to which they were least sensitive.

A comparison of two approaches to training visual analysis of AB graphs.

Visual analysis is the primary method of evaluating data in single-subject research. Few studies have evaluated interventions to teach visual analys is skills. The purpose of this study was to evaluate systematic instruction, delivered using computer-based intervention or a recorded lecture, on identifying changes in slope and level in AB graphs. Results indicated that both approaches were significantly more effective than a no-treatment control condition but were not different from each other. We discuss the implications of these results for training and directions for future research.

Generalization of negatively reinforced mands in children with autism.

Each day, people encounter stimuli they find unpleasant. Some children with autism may require systematic instruction to acquire the communication skills necessary to request the termination of such aversive stimuli. We taught 2 school-aged boys with autism a mand (e.g., signing "stop") that could be used to escape a variety of aversive stimuli. First, we employed a systematic assessment to identify aversive stimuli to use during training. We then conducted mand training sequentially across those stimuli until sufficient exemplars were trained for generalization to occur to untrained stimuli. For both participants, cross-stimulus generalization was observed after training with 2 stimuli. Participants manded for escape in the presence of aversive stimuli, but almost never manded in the presence of preferred stimuli or when the programmed stimuli were absent. In addition, we found an inverse relation between acquisition of the mand and engagement in problem behavior and evidence of generalization to nontraining contexts.

The Evidence-Based Practice of Applied Behavior Analysis.

Evidence-based practice (EBP) is a model of professional decision-making in which practitioners integrate the best available evidence with client values/context and clinical expertise in order to provide services for their clients. This framework provides behavior analysts with a structure for pervasive use of the best available evidence in the complex settings in which they work. This structure recognizes the need for clear and explicit understanding of the strength of evidence supporting intervention options, the important contextual factors including client values that contribute to decision making, and the key role of clinical expertise in the conceptualization, intervention, and evaluation of cases. Opening the discussion of EBP in this journal, Smith (The Behavior Analyst, 36, 7-33, 2013) raised several key issues related to EBP and applied behavior analysis (ABA). The purpose of this paper is to respond to Smith's arguments and extend the discussion of the relevant issues. Although we support many of Smith's (The Behavior Analyst, 36, 7-33, 2013) points, we contend that Smith's definition of EBP is significantly narrower than definitions that are used in professions with long histories of EBP and that this narrowness conflicts with the principles that drive applied behavior analytic practice. We offer a definition and framework for EBP that aligns with the foundations of ABA and is consistent with well-established definitions of EBP in medicine, psychology, and other professions. In addition to supporting the systematic use of research evidence in behavior analytic decision making, this definition can promote clear communication about treatment decisions across disciplines and with important outside institutions such as insurance companies and granting agencies.