multiple baseline design disadvantages

According to conventional wisdom, concurrent multiple baselines are superior because they allow for across-tier comparisons that can rule out coincidental events. Google Scholar. Third, patterns of results influence the number of tiers needed to yield definitive conclusions. Table 1 summarizes these threats to internal validity and the dimension of lag necessary to control for each. This has been the sharpest point of criticism of nonconcurrent multiple baselines. As Kazdin and Kopel (1975) pointed out, multiple baseline designs require that the effects of the independent variable must have tier-specific effects, yet the across-tier analysis requires that extraneous variables must not have tier-specific effects. Sometimes, the multiple baseline design may be more appropriate to use in interventions with small sample 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. First, the design assumes that treatment effects will be tier-specific and not spread to untreated tiers. WebMultiple-Baseline Designs There are two potential problems with the reversal designboth of which have to do with the removal of the treatment. The multiple baseline design for evaluating population Multiple-Baseline Design: Definition & Examples These could include presence of observers, testing procedures, exposure to testing stimuli, attention from implementers, being removed from the typical setting, exposure to a special setting, and so on. Routledge/Taylor & Francis Group. Three phonological patterns were targeted for each child. Routledge. The current SCD methodological literature and most SCD textbooks claim that because the tiers of nonconcurrent multiple baseline are not synchronized in real time they have a diminished capacity to control for extraneous variables, in particular coincidental events (e.g., Carr, 2005; Gast et al., 2018; Harvey et al., 2004; Johnston et al., 2020). Each of these three types of threats point us to distinct dimensions of the lag between phase changes that must be controlled for in order to achieve experimental control: for maturation, we control for elapsed time (e.g., days); for testing and session experience, we must be concerned with the number of sessions; and for coincidental events, we must be concerned with the specific time periods (i.e., calendar dates) of the study. Multiple baseline designs can rigorously control these threats to internal validity. The replicated within-tier analysis looks to patterns of results within the other tiers. Watson and Workman described a nonconcurrent multiple baseline design in which participants could be begin a study as they became known to the researcher. Use of brief experimental analyses in outpatient clinic and home settings. How many tiers do we need? Cooper, J. O., Heron, T. E., & Heward, W. L. (2020). Type I errors and power in multiple baseline designs. If we observe a potential treatment effect in one tier and corresponding changes in untreated tiers after similar amounts of time (i.e., number of days), maturation becomes a more plausible alternative explanation of the initial potential treatment effect. Multiple baseline designs are the workhorses of single-case design (SCD) research and are the predominant design used in modern applied behavior analytic research (Coon & Rapp, 2018; Cooper et al., 2020). Multiple baseline procedure. Therefore, concurrent and nonconcurrent designs are virtually identical in control for testing and session experience. Campbell, D. T., & Stanley, J. C. (1963). 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. However, this kind of support is not necessary: lagged replications of baseline predictions being contradicted by data in the treatment phase provide strong control for all of these threats to internal validity. The across-tier comparison is an additional basis for evaluating alternative explanations. (p. 325), Compared to its concurrent multiple baseline design sibling, a non-concurrent arrangement is inherently weaker . - 181.212.136.34. For example, there is less room for participant-level coincidental events if all participants reside in a single group home than if they reside in different group homes in different states. Rand McNally. Single-case research designs: Methods for clinical and applied settings (3rd ed.). Pearson Education. If a nonconcurrent multiple baseline has a long lag in real time between phase changes (e.g., weeks or months), this may provide stronger control than a design with a lag of one or several days. (2020) make a somewhat different methodological criticism of nonconcurrent multiple baseline designs. This is a preview of subscription content, access via your institution. Oxford University Press. Application of multiple baseline designs in behavior analytic research: Evidence for the influence of new guidelines. 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. We can identify at least three general categories of issues that influence the number of tiers required to render threats implausible: challenges associated with the phenomena under study, experimental design features, and data analysis issues. For example, in a study of language skills in typically developing 3-year-old children, maturation would be a particular concern. The multiple baseline family of designs includes multiple baseline and multiple probe designs. Create the graph from the data in Sheets; 3. Threats to Internal Validity in Multiple-Baseline Design Variations. Journal of Consulting & Clinical Psychology, 49(2), 193211. Correspondence to Because experimental circumstances and design elements vary so greatly, no universal answer can be given. However, each replication of the possible treatment effect that takes place at a substantially distinct calendar date reduces the plausibility of this threat. Based on the logic laid out in this article, we believe that the treats of maturation and testing and session experience are controlled equivalently in concurrent and nonconcurrent design. Kazdin, A. E. (2021). because a non-concurrent design does not allow any AB comparisons across baselines, it omits the opportunity to see if responding under the control condition changes when the treatment condition is implemented in the other baseline. Exceptional Children, 71, 165179. The non-concurrent multiple baseline across-individuals design: An extension of the traditional multiple baseline design. and (2) Was any change the result of the independent variable? In the past, there was significant controversy regarding the relative rigor of concurrent and nonconcurrent multiple baseline designs. https://doi.org/10.4324/9781315537085. Journal of Behavior Therapy & Experimental Psychiatry, 12(3), 257259. Both concurrent and nonconcurrent multiple baseline designs also afford the same across-tier comparison; both can show a potentialtreatment effect after a certain number of baseline sessions in one tier and a lack of effect after that same number of sessions in another tier. Baer, D. M., Wolf, M. M., & Risley, T. R. (1968). Multiple baseline and multiple probe designs. Maturation refers to extraneous variables such physical growth, physiological changes, typical interactions with social and physical environments, academic instruction, and behavior management procedures that tend to cause changes in behavior over time (cf., Shadish et al., 2002). WebThe first quality of ideal baseline data is stability, meaning that they display limited variability. Article et al. https://doi.org/10.1901/jaba.1968.1-91, Article It is interesting that this emphasis on across-tier comparisons is the opposite of that evident in Baer et al. Longer lags and more isolated tiers can reduce the number of tiers necessary to render extraneous variables implausible explanations of results. This insensitivity is not due to poor experimental design or implementation, it is built in to the nature of multiple baseline designs across participants. . Reversal Designs - University of Idaho The Family of Single-Case Experimental Designs PubMed 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. Therefore, we view this approach as less desirable than the standard multiple baseline design across subjects and suggest that it should be employed only when the standard approach is not feasible. If either of these assumptions are not valid for a coincidental event, then the presence and function of that event would not be revealed by the across-tier analysis. Throughout this article we have argued that controlling for the three main threats to internal validitymaturation, testing and session experience, and coincidental eventsin multiple baseline designs requires attention to three distinct dimensions of lag of phase changes across tiers. However, the specific issues in this controversy have never been thoroughly identified, discussed, and resolved; and instead a consensus emerged without the issues being explicitly addressed. 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. A study may be at heightened risk of coincidental events if the target behavior is particularly sensitive to events in the environment that are uncontrolled by the experimenter. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. 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. Chapter 8 Multiple Baseline Designs - Florida Without these dimensions of lag explicitly stated in the definition, we cannot claim that multiple baseline designs will necessarily include the features required to establish experimental control. PubMed Central The dimension of time is recognized in the requirement that phase changes be lagged in real timethat is, the date on which the phase changes are made. For example, knowing the date of session 10 in tier 1 tells us nothing about the date of session 10 in tier 2. Ten sessions of baseline would be expected to have similar effects whether they occur in January or June. WebIdentify the limitations of multiple baseline design 1.Does not demonstrate experimental control directly 2Provides more information about effectiveness of treatment That is, session numbers do not necessarily correspond to the same periods of real time across tiers. 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. The logic of replicated within-tier analysis applies equally to concurrent and nonconcurrent designs. 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. Slider with three articles shown per slide. Single-case research designs: Methods for clinical and applied settings (3rd ed.). If an extraneous variable were to have a tier-specific effect, it would be falsely interpreted as a treatment effect. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. They argue that because nonconcurrent multiple baseline designs lack an across-tier comparison in real time (the criticism described above), they cannot verify the prediction of the behavior pattern in the absences of intervention. 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. Craig H. Kennedy. Multiple Baseline Designs Concurrent and nonconcurrent multiple baseline designs address maturation in virtually identical ways through both within- and across-tier comparisons. Further, it is impossible to know how many events, which events, or the severity of the events that are missed by an across-tier comparison. This controversy began soon after the first formal description of nonconcurrent multiple baseline designs by Hayes (1981) and Watson and Workman (1981). Two articles published in 1981 described and advocated the use of nonconcurrent multiple baseline designs (Hayes, 1981; Watson & Workman, 1981). Barlow, D. H., Nock, M. K., & Hersen, M. (2009). Third, we explore how concurrent and nonconcurrent multiple baselines address each of the main threats to internal validity. Given this dilemma, priority should be given to optimizing the within-tier comparisons because this is the comparison that can confer stronger control. Single-Subject Research Designs Research Methods in 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. In this article, we argue that the primary reliance on across-tier comparisons and the resulting deprecation of nonconcurrent designs are not well-justified. Harvey, M. T., May, M. E., & Kennedy, C. H. (2004). Poor execution can certainly worsen these problems, but good execution cannot eliminate them. Alternating Treatment Designs Watch on What are the disadvantages of alternating treatments? Perspectives on Behavior Science, 43, 605616. PubMedGoogle Scholar. First, studies differ with respect to the experimental challenges imposed by the phenomena under study. 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. 2023 Springer Nature Switzerland AG. 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. Taplin, P. S., & Reid, J. Experimental and quasi-experimental designs of research. The across-tier comparison is valuable primarily when it suggests the presence of a threat by showing a change in an untreated tier at approximately the same time (i.e., days, sessions, or dates) as a potential treatment effect. 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. Houghton Mifflin. Rosales-Ruiz, J., & Baer, D. M. (1997). Multiple baseline and changing criterion design Flashcards 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. In this case, the across-tier comparison would give the false appearance of strong internal validity. Wacker, D., Berg, W., Harding, J., & Cooper-Brown, L. (2004). The general steps for the development of the line graphs are as follows: 1. Advantages and Disadvantages of ABA Design. (2011). Finally, we make recommendations for more rigorous use, reporting, and evaluation of multiple baseline designs. Part of Springer Nature. The bottom line is that the experimenter can never know whether a coincidental event has contacted only a single tier of a concurrent multiple baseline and, therefore, whether it is possible for the across-tier comparison to detect this threat. Likewise, in a multiple baseline across settings, selecting settings that tend to share extraneous events would make the across-tier analysis more powerful than would selecting settings that share few common events. It is possible that a coincidental event may be present for all tiers but have different effects on different tiers. Second, the across-tier comparison assumes that extraneous variables will affect multiple tiers similarly. The functional answer to this question is that there must be sufficient tiers so that none of the threats to internal validity are plausible explanations for the pattern of effects across the set of tiers. Nonconcurrent multiple baseline designs, however, do not afford this comparison. WebThe main disadvantage of the multiple baseline design is that a high degree of planning is required to produce a successful implementation. (pp. A functional relation can be inferred if the pattern of data demonstrates experimental controlthe experimenters ability to produce a change in the dependent variable in a precise and reliable fashion (Sidman, 1960). By synchronized we mean that session 1 in all tiers takes place before session 2 in any tier, and this ordinal invariance of session number across tiers is true for all sessions. As Kazdin and Kopel point out, it is clearly possible for treatments to have broad effects on multiple tiers and for extraneous variables to have narrow effects on a specific tier. cycles approach: a multiple baseline Thus, to the degree that nonconcurrent designs support longer lags between phases changes than concurrent designs, they may support stronger control of the threat of coincidental events through replicated within-tier comparisons. Consequently, it is often difficult or impossible to dismiss rival hypotheses or explanations. Rather, the passage of time allows for more opportunities for participants to interact with their environmentleading to maturational changes. Behavioral Assessment, 7(2), 129132. Basic Books. 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. These observations lead us to the conclusion that neither of the critical assumptions that coincidental events will (1) contact and (2) have similar impact on all tiers can be assumed to be valid. For example, instrumentation is addressed primarily through observer training, calibration, and IOA. Hayes, S. C. (1981). On the other hand, across-tier comparisons may be strengthened by arranging tiers to be as similar as possible so that they would be more likely to be exposed to the same coincidental events. 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. Johnston, J. M., Pennypacker, H. S., & Green, G. (2010). As we mentioned above, across-tier comparisons require the assumptions that coincidental events will (1) contact and (2) have similar effects on all tiers of the design. This paper describes procedures for using these designs, The time lag must be sufficiently long so that no single event could produce potential treatment effects in more than one tier. Instead, the idea that lag across phase changes includes three important dimensions and that these lags are critical for establishing experimental control and justifying strong causal conclusions should be elevated in importance. https://doi.org/10.1037/0022-006X.49.2.193. They do not elaborate on the importance of this type of comparison. The Nonconcurrent Multiple-Baseline Design: It is What it Coincidental events include divorce, changing of living situation, changes in school or work schedule, physical injury, changes in a setting such as construction, changes in coworkers or staffing, and many others. The within-tier analysis seeks replication of these potential treatment effects in additional tiers of the design. Psychological Methods, 17(4), 510550. When conditions are less ideal, additional tiers may be necessary. Interrater agreement on the visual analysis of individual tiers and functional relations in multiple baseline designs. Multiple baseline designsboth concurrent and nonconcurrentare the predominant experimental design in modern applied behavior analytic research and are increasingly employed in other disciplines. The author has no known conflicts of interest to disclose. So, for example, session 10 in tier 2 must take place at some time between tier 1s session 9 and 11. The authors discuss two designs commonly used to demonstrate reliable control of an important behavior change (p. 94). Single case experimental designs: Strategies for studying behavior change (3rd ed.). Journal of Consulting & Clinical Psychology, 49(2), 193211. In this design, behavior is measured across either multiple individuals, behaviors, or settings. Sidman, M. (1960). This argument rests on the assumptions that any extraneous variable that affects one tier will (1) contact all tiers and (2) have a similar effect on all tiers. The strength of this control is a function of our certainty that no single coincidental event could have caused more than one change in the dependent variable. https://doi.org/10.3758/s13428-011-0111-y, Article Second, we briefly summarize historical methodological writing and current textbook treatment of these designs. A potential treatment effect in any single tier could plausibly be explained as a result of a coincidental event. Although the across-tier comparison may detect some coincidental events; it cannot be assumed to detect them all. When determining whether a multiple baseline study demonstrates experimental control, researchers examine the data within and across tiers and also consider the extent to which alternative explanations (e.g., extraneous variables or confounds) could plausibly account for the obtained data patterns. Multiple However, it does not rule out maturation as an alternative explanation of the change in behavior. That is, experimental control has not been convincingly demonstrated. Multiple Baseline Flashcards | Quizlet 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 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. 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. Small n Designs: ABA & Multiple-Baseline Designs 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. Throughout their discussion of SCD, these authors describe experimental control in terms of three processes: prediction, verification, and replication. Testing and session experience encompasses features of experimental sessions (both baseline and intervention phases) other than the independent variable that could cause changes in behavior. Single Subject Design Guide - Eastern Michigan University A baseline (A) and an intervention (B) are included in a straightforward AB design psychological experiment (B). In addition, arranging tiers that are isolated in other dimensions (e.g., location, behaviors, participants) confers overall strength, not weakness, for addressing coincidental events. Peer reviewers and editors who serve as gatekeepers for the scientific literature must also have a deep understanding of these issues so that they can distinguish between stronger and weaker research, ensure that information critical to evaluating internal validity is included in research reports, and assess the appropriateness of discussion and interpretation of results. The across-tier comparison of concurrent multiple baseline designs is less certain and definitive than it may appear. (p. 206). Chapter 9: Multiple Baseline And Changing Criterion 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). After implementing the treatment for the first tier, they say, rather than reversing the just produced change, he instead applies the experimental variable to one of the other as yet unchanged responses. Textbooks commonly describe and characterize the design without clearly defining it. 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. PubMed There is ample empirical evidence of differential impact of variables across tiers. Create the data table in Sheets; 2. They never raise the question of whether replicated within-tier comparisons are sufficient to rule out threats to internal validity and establish experimental control. Smith, J. D. (2012). Data from the treatment phase in one tier can be compared to corresponding baseline data in another tier. 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. Potential setting-level events include staffing changes in classroom, redecoration or renovation of the physical environment, and changes in the composition of the peer group in a classroom, group home, or worksite.
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