multiple baseline design disadvantages multiple baseline design disadvantages

Some current dimensions of applied behavior analysis. Thus, the assumption that the coincidental event contacts all tiers would be valid and the across-tier analysis might reveal the effects of this sort of event. If it changes at that point, evidence is accruing that the experimental variable is indeed effective, and that the prior change was not simply a matter of coincidence (p. 94). Behavior Research Methods, 43(4), 971980. Behavioral Interventions, 33(2), 160172. Although the across-tier comparison may detect some coincidental events; it cannot be assumed to detect them all. Threats to Internal Validity in Multiple-Baseline Design Variations, https://doi.org/10.1007/s40614-022-00326-1, Concurrence on Nonconcurrence in Multiple-Baseline Designs: A Commentary on Slocum et al. Google Scholar, Harvey, M. T., May, M. E., & Kennedy, C. H. (2004). However, in a concurrent multiple baseline across participants, participant-level events contact only a single tier (participant)the coincidental event would not contact other tiers (participants)we might say that the across-tier analysis is inherently insensitive to detecting this kind of event. Therefore, researchers must exercise extreme caution in interpreting and generalizing the results from pre-experimental studies. 234235). Throughout this article we have referred to the importance of replicating within-tier comparisons, emphasizing the idea that tiers must be arranged with sufficient lag in phase changes so that specific threats to internal validity are logically ruled out. Google Scholar. the effects of the treatment variable are inferred from the untreated behaviors (p. 227). The issue of concurrence of tiers should be considered along with many other design variations that can be manipulated to create a design that fits the particular experimental challenges of a particular study. It is possible that a coincidental event may be present for all tiers but have different effects on different tiers. Small n Designs: ABA & Multiple-Baseline Designs However, as Hayes (1985) pointed out, even with the most rigorous care in experimental design, we can never give two individuals the same experiences outside of our experimental sessions. The vast majority of contemporary published multiple baseline designs describe the timing of phases in terms of sessions rather than days or dates. 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. Finally, we make recommendations for more rigorous use, reporting, and evaluation of multiple baseline designs. Features of the target behaviors, participants, measurement, and so forth can make threats to internal validity more or less likely. Adding multiple tiers to the design allows for two types of additional comparisons to be used to evaluate, and perhaps rule out, these threats: (1) replications of baseline-treatment comparisons within subsequent tiers (i.e., horizontal analysis), and (2) comparisons across tiers (i.e., vertical analysis). So, for example, session 10 in tier 2 must take place at some time between tier 1s session 9 and 11. Oxford. WebOften creates lots of problems BAB Reversal Design Doesnt enable assessment of effects prior to the intervention May get sequence effects May be appropriate with dangerous behaviors Addresses ethics of withholding effective treatment Need to be careful when using NCR Reversal Technique Noncontingent reversal Single-case designs for educational research. This raises the question of how many replications are necessary to establish internal validity. This assumption was initially identified by Kazdin and Kopel in 1975, but its implications for the rigor of the across-tier comparison have rarely been discussed since that time. Journal of Behavioral Education, 13, 267276. Characteristics of single-case designs used to assess intervention effects in 2008. Textbooks commonly describe and characterize the design without clearly defining it. Coincidental events might be expected to be more variable in their effect than interventions that are designed to have consistent effects. The nature of control for coincidental events (i.e., history) provided by the within-tier comparison in both concurrent and nonconcurrent multiple baseline designs is relatively straightforward. Hersen, M., & Barlow, D. H. (1976). This control assumes that the replications are sufficiently offset in real time (e.g., calendar days) to ensure that a single coincidental event could not plausibly cause the effects observed in multiple tiers. WebWhat are some disadvantages of alternating treatment design? We will focus on the three types of threats that are addressed through comparisons between baseline and treatment phases in multiple baseline designs: maturation, testing and session experience, and coincidental events.Footnote 1. Tactics of scientific research. WebMULTIPLE BASELINE DESIGN Most widely used for evaluating treatment effects in ABA Highly flexible Do not have to withdraw treatment variable Is an alternative to reversal In a concurrent multiple baseline that involves a single participant across settings, behaviors, antecedent stimuli etc., this kind of event would be expected to contact all tiers. Neither the within-tier comparison, nor the across-tier comparison depends on the tiers being conducted simultaneously; both types of comparisons only require that phase changes occur after substantially different amounts of time since the beginning of baselinethat is, each tier is exposed to different amounts of maturation (i.e., days) prior to the phase change. The present article is focused on the second questionwhether systematic changes in data can be attributed to the treatment. Other threats to internal validity such as (1) ambiguous temporal precedence, (2) selection, (3) regression, (4) attrition, and (5) instrumentation are addressed primarily through other design features. Anyone you share the following link with will be able to read this content: Sorry, a shareable link is not currently available for this article. It is interesting that this emphasis on across-tier comparisons is the opposite of that evident in Baer et al. When changes in data occur immediately after the phase change, are large in magnitude, and are consistent across tiers, threats to internal validity tend to be less plausible explanations of the data patterns, and fewer tiers would be required to rule them out. In both within- and across-tier comparisons, the dates on which the sessions took place are not relevant to the effects of testing and session experience. Throughout their discussion of SCD, these authors describe experimental control in terms of three processes: prediction, verification, and replication. It would be an even greater concern if the treatment were an instructional program that requires several weeks or months to implement. Nonconcurrent multiple baseline designs for educational program evaluation. For example, for a child who is on the cusp of walking, a month of exposure to maturational variables may result in a significant improvement in walking, but much less change in fine motor skills. In concurrent multiple baseline across participants, behaviors, or stimulus materials that take place in a single setting, this kind of event would contact all the tiers of the multiple baseline. They do not elaborate on the importance of this type of comparison. Kennedy, C.H. WebIn yet a third version of the multiple-baseline design, multiple baselines are established for the same participant but in different settings. These coincidental events would contact all tiers of a multiple baseline that include this individual participant, but not tiers that do not involve this participant. While the fact that the researcher does not use a large number of participants has its advantages, it also has a downside: Because the experimental trials are run on only one subject, it is difficult to empirically show with the experiment's data that the findings will generalize out to larger populations. In particular, within-tier comparisons may be strengthened by isolating tiers from one another in ways that reduce the chance that any single coincidental event could coincide with a phase change in more than one tier (e.g., temporal separation). Having identified the criticisms of nonconcurrent multiple baseline designs, we now turn to a detailed analysis of threats to internal validity and features that can control these threats. The concurrent multiple baseline design opened up many new opportunities to conduct applied research in contexts that were not amenable to other SCDs. They never raise the question of whether replicated within-tier comparisons are sufficient to rule out threats to internal validity and establish experimental control. In order to meet the terms of the definition, and confirm the critical characteristics for controlling threats to internal validity, we recommend that all multiple baseline studies explicitly report, for each tier, the number of days and sessions in each phase, and the number of calendar days of phase change lag from the previous tier. Further, if the potential treatment effect is more gradual (as one might expect from an educational intervention on a complex skill), maturational changes may be impossible to distinguish from treatment effects. Attachment L: Strengths and Limitations of the Single The key characteristic that maturational processes share is that they may produce behavioral changes that would be expected to accumulate as a function of elapsed time in the absence of participation in research.Footnote 2 In order to control for maturation, we must attend to the passage of timetypically, calendar days. WebNew Mexico's Flagship University | The University of New Mexico Taplin, P. S., & Reid, J. Slocum, T.A., Pinkelman, S.E., Joslyn, P.R. A COMPARISON OF MULTIPLE BASELINE FAMILY OF https://doi.org/10.1177/0741932512452794, Lanovaz, M. J., & Turgeon, S. (2020). Three phonological patterns were targeted for each child. Chapter 8 Multiple Baseline Designs - Florida (pp. The multiple baseline family of designs includes multiple baseline and multiple probe designs. Smith, J. D. (2012). This has been the topic of important recent methodological research, including studies of the interobserver reliability of expert judgements of changes seen in published multiple baseline designs (Wolfe et al., 2016) and use of simulated data to test Type I and II error rates when judgements of experimental control are made based on different numbers of tiers (Lanovaz & Turgeon, 2020). Kazdin, A. E. (2021). If a potential treatment effect is observed in the treated tier but a change in the dependent variable is also observed in corresponding sessions in a tier that is still in baseline, this provides evidence that an extraneous variable may have caused both changes. Timothy A. Slocum. Single-case research designs: Methods for clinical and applied settings (3rd ed.). In the case of multiple baseline designs, a stable baseline supports a strong prediction that the data path would continue on the same trajectory in the absence of an effective treatment; these predictions are said to be verified by observing no change in trajectories of data in other tiers that are not subjected to treatment; and replication is demonstrated when a treatment effect is seen in multiple tiers. Thus, for any multiple baseline design to address the threat of maturation, it must show changes in multiple tiers after substantially differing numbers of days in baseline. Pearson Education. Thus, to demonstrate experimental control, the effects of the independent variable must not generalize; and to detect an extraneous variable through the across-tier comparison, the effects of that extraneous variable must generalize. What are the benefits and problems of these designs? Although it is plausible that an extraneous variables influence could coincide with one phase change, it is less plausible that such a coincidence would occur twice, and even less plausible that it would occur three times. (2020) make a somewhat different methodological criticism of nonconcurrent multiple baseline designs. In this article, we first define multiple baseline designs, describe common threats to internal validity, and delineate the two bases for controlling these threats. The across-tier comparison of concurrent multiple baseline designs is less certain and definitive than it may appear. This insensitivity is not due to poor experimental design or implementation, it is built in to the nature of multiple baseline designs across participants. To summarize, the replicated within-tier analysis with sufficient lag can rigorously control for the threat of maturation. This might be conveniently reported in the methods section or a small table in an appendix. Multiple Baseline Designs - University of Idaho a potential treatment effect in the first tier would be vulnerable to the threat that the changes in data could be a result of https://doi.org/10.1002/bin.1510. must have stable baseline and tx in first bx Multiple baseline designs can rigorously control these threats to internal validity. Because experimental circumstances and design elements vary so greatly, no universal answer can be given. Thus, a multiple baseline with phase changes sufficiently lagged (in terms of number of sessions) provides rigorous control for this threat. Single case experimental designs: Strategies for studying behavior change (3rd ed.). https://doi.org/10.1177/001440290507100203, Johnston, J. M., Pennypacker, H. S., & Green, G. (2020). Applied behavior analysis (3rd ed.). Any of these types of circumstances may require additional tiers in order to clearly address threats to internal validity. Two articles published in 1981 described and advocated the use of nonconcurrent multiple baseline designs (Hayes, 1981; Watson & Workman, 1981). https://doi.org/10.1023/B:JOBE.0000044735.51022.5d, Hayes, S. C. (1981). Controlling for coincidental events requires attention to the specific dates on which events occur. The Nonconcurrent Multiple-Baseline Design: It is What it is and Not Something Else. This comparison can reveal the influence of an extraneous variable only if it causes a change in several tiers at about the same time. WebGive two advantages and two disadvantages of quasi-experimental designs. First, in the replicated within-tier comparison, each tier of the design is exposed to the treatment at a different point in time. The time lag must be sufficiently long so that no single event could produce potential treatment effects in more than one tier. This consensus is that nonconcurrent multiple baseline designs are substantially weaker than concurrent designs (e.g., Cooper et al., 2020; Johnston et al., 2020; Kazdin, 2021). (1973). Consequently, it is often difficult or impossible to dismiss rival hypotheses or explanations. Johnston, J. M., Pennypacker, H. S., & Green, G. (2010). In addition, multiple baseline designs are increasingly used in literatures that are not explicitly behavior analytic. This is consistent with the judgements made by numerous existing standards and recommendations (e.g., Gast et al., 2018; Horner et al., 2005; Kazdin, 2021; Kratochwill et al., 2013). and (2) Was any change the result of the independent variable? The first is the reversal design and the authors describe the important applied limitation with this designsituations in which reversals are not possible or feasible in applied settings. Data from the treatment phase in one tier can be compared to corresponding baseline data in another tier. Nonconcurrent multiple baseline designs, however, do not afford this comparison. Carr, J. E. (2005). ), Single case research methodology: Applications in special education and behavioral sciences (pp. For example, instrumentation is addressed primarily through observer training, calibration, and IOA. The multiple baseline design for evaluating population Interrater agreement on the visual analysis of individual tiers and functional relations in multiple baseline designs. The multiple baseline design was initially described by Baer et al. Provided by the Springer Nature SharedIt content-sharing initiative, Over 10 million scientific documents at your fingertips, Not logged in Journal of Applied Behavior Analysis, 1(1), 9197. In such an instance, there may be a disruption to experimental control in only one-tier of the design and not others, thus influencing the degree of internal Threats to Internal Validity in Multiple-Baseline Design Variations. Concurrence is not necessary to detect and control for maturation. WebWeaknesses of multiple baseline designs: There are certain functional relations that may not be clearly understood by this design This design is time consuming and Nonconcurrent multiple baseline designs and the evaluation of educational systems. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. The assumption that all tiers respond similarly to maturation may be somewhat more problematic. The authors discuss two designs commonly used to demonstrate reliable control of an important behavior change (p. 94). Other design features that contribute to the isolation of tiers such that any single extraneous variable is unlikely to contact multiple tiers can also strengthen the independence of tiers. Or in a multiple baseline across settings that are assessed at different times of the day, a socially challenging event such as an increase in daily bullying on a morning bus ride could disrupt the target behavior of a participant for the first hour of the day, but have reduced effects thereafter. PubMed Central The details of situations in which this across-tier comparison is valid for ruling out threats to internal validity are more complex than they may appear. This question cannot be addressed by data analysis alone; any pattern of data, no matter how dramatic, could be a result of an extraneous variable if the experimental design features are not properly arranged. - 216.238.99.111. For the purposes of this article, we define a multiple baseline design as a single-case experimental design that evaluates causal relations through the use of multiple baseline-treatment comparisons with phase changes that are offset in (1) real time (e.g., calendar date), (2) number of days in baseline, and (3) number of sessions in baseline. cycles approach: a multiple baseline WebExtended baselines or interventions may threaten experimental control, delayed intervention may pose a risk to client or others as an ethical concern. That is, session numbers do not necessarily correspond to the same periods of real time across tiers. Coincidental events (i.e., history) are specific events that occur at a particular time (or across a particular period) and could cause changes in behavior. Cooper, J. O., Heron, T. E., & Heward, W. L. (2020). PubMedGoogle Scholar. Multiple baseline designsboth concurrent and nonconcurrentare the predominant experimental design in modern applied behavior analytic research and are increasingly employed in other disciplines. Google Scholar. If a potential treatment effect is seen in one tier and on the same day there is no change in other tiers, this is taken as strong evidence that the potential treatment effect was not a result of a coincidental event, because a coincidental event would have had an effect on all tiers. Ab design advantages simple to use In this article, we argue that the primary reliance on across-tier comparisons and the resulting deprecation of nonconcurrent designs are not well-justified. Any alternative explanation of this pattern of results would have to posit an alternative set of causes that could plausibly result in changes in the dependent variable in this specific pattern across the multiple tiers. Reversal Designs - University of Idaho A critical requirement of the within-tier analysis is that no single extraneous event could plausibly cause the observed changes in multiple tiers. The across-tier comparison is an additional basis for evaluating alternative explanations. Data analysis issues concern two closely related questions: (1) Was there a change in data patterns after the phase change? Use of brief experimental analyses in outpatient clinic and home settings. https://doi.org/10.1016/S0005-7894(75)80181-X, Kratochwill, T. R., Hitchcock, J., Horner, R. H., Levin, J. R., Odom, S. L., Rindskopf, D. M., & Shadish, W. R. (2013). Campbell, D. T., & Stanley, J. C. (1963). Perspectives on Behavior Science This paper describes procedures for using these designs, For example, in a multiple baseline across participants, all the residents of a group home may contact peanut butter and jelly sandwiches for lunch but this change may disrupt the behavior of residents with a mild peanut allergy, but not other residents. Instead, a detailed understanding of how specific threats to internal validity are addressed in multiple baseline designs and specific design features that strengthen or weaken control for these threats are needed. Type I Errors and Power in Multiple Baseline Designs, Assessing consistency of effects when applying multilevel models to single-case data. Attachment L: Strengths and Limitations of the Single- Subject A multiple baseline design with tiers conducted at different times during each day could show disruption due to this coincidental event in the tier assessed early in the day but not in tiers that are assessed later in the day. Campbell, D. T., & Stanley, J. C. (1963). Watson and Workman (1981) noted that the requirement that observations be taken concurrently clearly poses problems for researchers in applied settings (e.g., schools, mental health centers), since clients with the same target behavior may only infrequently be referred at the same point in time (p. 257). Correspondence to https://doi.org/10.1007/s40614-022-00343-0, SI: Commentary on Slocum et al, Threats to Internal Validity. Behavioral Interventions, 20(3), 219224. Part of Springer Nature. Independent from Watson and Workman (1981), Hayes (1981) published a lengthy article introducing SCDs to clinical psychologists and made the point that these designs are well-suited to conducting research in clinical practice. Google Scholar, Gast, D. L., Lloyd, B. P., & Ledford, J. R. (2018). Single-case experimental designs: A systematic review of published research and current standards. If session experience exerted a small degree of influence on the DV, an effect might be observed in settings where the behavior is more likely, but not in settings where the behavior is less likely. The lag between phase changes must be long enough that maturation over any single amount of time cannot explain the results in multiple tiers. An alternative explanation would have to suggest, for example, that in one tier, experience with 5 baseline sessions produced an effect coincident with the phase change; in a second tier, 10 baseline sessions had this effect, again coinciding with the phase change; and in a third tier, 15 baseline sessions produced this kind of change and happened to correlate with the phase change. First, studies differ with respect to the experimental challenges imposed by the phenomena under study. On resolving ambiguities of the multiple-baseline design: Problems and recommendations. We will explore these issues extensively after we sketch the historical development of multiple baseline designs and criticisms of nonconcurrent multiple baselines. This critical requirement is mainly addressed by the lag between phase changes in successive phases. https://doi.org/10.1016/0005-7916(81)90055-0, Wolfe, K., Seaman, M. A., & Drasgow, E. (2016). Single case experimental design and empirical clinical practice. They describe the control afforded by the design: The experimenter is assured that his treatment variable is effective when a change in rate appears after its application while the rate of concurrent (untreated) behaviors remains relatively constant (p. 226). And researchers generally design and implement interventions, select tiers, and employ measures that will likely show consistent treatment effects. A close examination of threats to internal validity in multiple baseline designs reveals and clarifies the critical design features that determine the degree of experimental control and internal validity of either type of multiple baseline. Single-case experimental designs: Strategies for studying behavior change. For example, it is implausible that the effects of maturation would coincide with a phase change after 5 days in one tier, after 10 days in a second tier, and after 15 days in a third. One is that if a With control for coincidental events in multiple baseline designs resting squarely on replicated within-tier comparisons, there is no basis for claiming that, in general, concurrent designs are methodologically stronger than nonconcurrent designs. Houghton Mifflin. In general, in a concurrent multiple baseline design across any factor, the across-tier analysis is inherently insensitive to coincidental events that are limited to a single tier of that factor. Journal of Behavioral Education, 13(4), 267276. Watson and Workman did not explicitly address threats to internal validity other than coincidental events. This would align the definition with the critical features required to demonstrate experimental control and thereby allow strong causal statements based on multiple baseline designs.