To summarize, the replicated within-tier analysis with sufficient lag can rigorously control for the threat of maturation. Kazdin, A. E. (2021). A baseline (A) and an intervention (B) are included in a straightforward AB design psychological experiment (B). Hayes argued that fortunately the logic of the strategy does not really require (p. 206) an across-tier comparison because the within-tier comparison rules out these threats. 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. - 181.212.136.34. 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. 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. For example, instrumentation is addressed primarily through observer training, calibration, and IOA. Events that contact a single participant may be termed participant-level. Alternating Treatment Designs Watch on What are the disadvantages of alternating treatments? The ABA or Reversal Design 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. https://doi.org/10.1007/s40614-022-00343-0, DOI: https://doi.org/10.1007/s40614-022-00343-0. An example of multiple baseline across behaviors might be to use feedback to develop a comprehensive exercise program that involves stretching, aerobic exercise, 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. 2023 Springer Nature Switzerland AG. 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. If an extraneous variable were to have a tier-specific effect, it would be falsely interpreted as a treatment effect. Examples could include family events, illness, changed social interactions (e.g., breaking up with a partner), losing or gaining access to a social service program, etc. Part of Springer Nature. 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. 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. Hayes, S. C. (1981). The across-tier comparison of concurrent multiple baseline designs is less certain and definitive than it may appear. In both forms of multiple baseline designs, a potential treatment effect in the first tier would be vulnerable to the threat that the changes in data could be a result of testing or session experience. In this case, the across-tier comparison would give the false appearance of strong internal validity. Smith, J. D. (2012). In addition, functionally isolating tiers (e.g., across settings) such that they are highly unlikely to be subjected to the same instances of a threat can also contribute to this goal. write that after implementing the treatment in an initial tier, the experimenter perhaps notes little or no change in the other baselines (p. 94). https://doi.org/10.1901/jaba.1968.1-91, Article Experimental and quasi-experimental designs for research. 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. The across-tier comparison is an additional basis for evaluating alternative explanations. 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. A critical requirement of the within-tier analysis is that no single extraneous event could plausibly cause the observed changes in multiple tiers. Later they present an overall evaluation of the strength of multiple baseline designs, attributing its primary weakness to its reliance on the across-tier comparison, The multiple baseline design is considerably weaker than the withdrawal design as the controlling effects of the treatment on each of the target behaviors is not directly demonstrated . However, researchers in clinical, educational, and other applied settings recognized that they could expand research much further if the tiers of a multiple baseline could be conducted as they became available sequentially rather than simultaneously. The within-tier comparison may be further strengthened by increasing independence of the tier in other dimensions. PubMed WebAnother limitation cited for single-subject designs is related to testing. Pearson Education. Testing and session exposure may be particularly troublesome in a study that requires taking the participant to an unusual location and exposing them to unusual assessment situations in order to obtain baseline data. Finally, we make recommendations for more rigorous use, reporting, and evaluation of multiple baseline designs. Additionally, the The lag between phase changes must be long enough that maturation over any single amount of time cannot explain the results in multiple tiers. When conditions are less ideal, additional tiers may be necessary. (Similar arguments can be made for comparisons across settings, persons, and other variables that might define tiers.) Google Scholar, Gast, D. L., Lloyd, B. P., & Ledford, J. R. (2018). The Family of Single-Case Experimental Designs WebGive two advantages and two disadvantages of quasi-experimental designs. In J. R. Ledford & D. L. Gast (Eds. Pearson Education. Data analysis issues concern two closely related questions: (1) Was there a change in data patterns after the phase change? a potential treatment effect in the first tier would be vulnerable to the threat that the changes in data could be a result of Rosales-Ruiz, J., & Baer, D. M. (1997). 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. 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. (1968) who emphasized the replicated within-tier comparison. 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. WebLike RCTs, the multiple baseline design can demonstrate that a change in behavior has occurred, the change is a result of the intervention, and the change is significant. Sometimes, the multiple baseline design may be more appropriate to use in interventions with small sample Table 1 summarizes these threats to internal validity and the dimension of lag necessary to control for each. 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. Describe the retrospective and prospective research designs. Without the latter you cannot conclude, with confidence, that the intervention alone is responsible for observed behavior changes since baseline (or probe) data are not concurrently collected on all tiers from the start of the investigation. It would be an even greater concern if the treatment were an instructional program that requires several weeks or months to implement. Second, we briefly summarize historical methodological writing and current textbook treatment of these designs. Learn more about Institutional subscriptions. The multiple baseline family of designs includes multiple baseline and multiple probe designs. chapter 9 Flashcards | Quizlet Using Single-Case Designs in Practical Settings: Is Within-Subject Replication Always Necessary? 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. The replicated within-tier analysis looks to patterns of results within the other tiers. Nonconcurrent multiple baseline designs for educational program evaluation. First, studies differ with respect to the experimental challenges imposed by the phenomena under study. Provided by the Springer Nature SharedIt content-sharing initiative, Over 10 million scientific documents at your fingertips, Not logged in Thus, although the across-tier analysis does provide a test of the maturation threat, a lack of change in untreated tiers cannot definitively rule it out. Reversal Designs - University of Idaho This certainty is increased by isolation of tiers in time and other dimensions. limitation of alternating treatment designs: o it is susceptible to multiple treatment interference, o rapid back-and-forth switching of treatments does not reflect the typical manner in which interventions are applied and may be viewed as artificial and undesirable. The non-concurrent multiple baseline across-individuals design: An extension of the traditional multiple baseline design. . Pergamon. 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 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). 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. First, in the replicated within-tier comparison, each tier of the design is exposed to the treatment at a different point in time. Single-case experimental designs: Strategies for studying behavior change. Given that multiple baseline designs make up such a large proportion of the existing SCD literature and current research activity, it is critical that SCD researchers thoroughly understand the specific ways that multiple baseline designs address potential threats to internal validity so that they can make experimental design decisions that optimize internal validity and accurately evaluate, discuss, and interpret the results of their research. Strategies and tactics of behavioral research. For example, Gast et al. The process begins with a simple baseline-treatment (AB) comparisona change from baseline to treatment within a single tier. These views of multiple baseline designs have been carried through into much of the single-case methodological literature and textbooks to the current day. 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). Kennedy, C.H. WebNew Mexico's Flagship University | The University of New Mexico Cooper et al. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. Second, as we have discussed above, the amount of lag between phase changes (in terms of sessions in baseline, days in baseline, and elapsed days) is the primary design feature that reduces the plausibility of any single threat accounting for changes in multiple tiers, and thereby threatening the internal validity of the design as a whole. Although many maturational changes are gradual, more sudden changes are possible. However, if this within-tier pattern is replicated in multiple tiers after differing numbers of baseline sessions, this threat becomes increasingly implausible. Natural multiple baselines across persons: A reply to Harris and Jenson. Ten sessions of baseline would be expected to have similar effects whether they occur in January or June. 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 Concurrence is not necessary to detect and control for maturation. Concurrent and nonconcurrent multiple baseline designs address maturation in virtually identical ways through both within- and across-tier comparisons. Multiple baseline and changing criterion design Flashcards Single-case intervention research design standards. For both types of comparisons, addressing maturation begins with an AB contrast in a single tier. If A changes after B is put into practice, a researcher can draw the Conclusion that B caused A to change. Craig H. Kennedy. 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). A coincidental event may contact a single unit of analysis (e.g., one of four participants) or multiple units (e.g., all participants). An important drawback of pre-experimental designs is that they are subject to numerous threats to their validity. 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. The across-tier analysis of coincidental events is the main way that concurrent and nonconcurrent multiple baselines differ. 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). Oxford. Journal of Behavioral Education, 13(4), 213226. https://doi.org/10.1002/bin.191, Article We have no known conflict of interest to disclose. Correspondence to One area that has, in the past, been particularly controversial is the experimental rigor of concurrent versus nonconcurrent multiple baseline designs; that is, the degree to which each can rule out threats to internal validity. 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. Predi Abab Design Essay If the pattern of change shortly after implementation of the treatment is replicated in the other tiers after differing lengths of time in baseline (i.e., different amounts of maturation), maturation becomes increasingly implausible as an alternative explanation. If, in the initial tier, a pattern of stable baseline data is followed by a distinct change soon after the phase change, this constitutes a potential treatment effect. Chapter 9: Multiple Baseline And Changing Criterion Although the design entails two of the three elements of baseline logicprediction and replicationthe absence of concurrent baseline measures precludes the verification of [the prediction]. Basic Books. This would draw attention to the relationship between the prediction from baseline and the (possible) contradiction of that prediction by the obtained treatment-phase data, and the replication of this prediction-contradiction pair in subsequent tiers. Any one tier may, at best, demonstrate a potential treatment effect; however, a set of three or more tiers may strongly address the threat of coincidental events and clearly demonstrate experimental control. Thus, both of the articles introducing nonconcurrent multiple baselines made explicit arguments that replicated within-tier comparisons are sufficient to address the threat of coincidental events. This has been the sharpest point of criticism of nonconcurrent multiple baselines. Three children (ages 4;3 to 5;3) with moderate-severe to severe SSDs participated in two cycles of therapy. In this case, the effects of this kind of event could be revealed through the across-tier comparison of participants or behaviors that have not been exposed to the independent variable. 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). PubMedGoogle Scholar. 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. 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). By nature, undetected events are unknown. Shadish, W. R., Cook, T. D., & Campbell, D. T. (2002). https://doi.org/10.1023/B:JOBE.0000044735.51022.5d, Hayes, S. C. (1981). 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. Coincidental events might be expected to be more variable in their effect than interventions that are designed to have consistent effects. Attachment L: Strengths and Limitations of the Single Estimating reliabilities and correcting for sampling error in indices of within-person dynamics derived from intensive longitudinal data, Optimizing Detection of True Within-Person Effects for Intensive Measurement Designs: A Comparison of Multilevel SEM and Unit-Weighted Scale Scores, https://doi.org/10.1023/B:JOBE.0000044735.51022.5d, https://doi.org/10.1037/0022-006X.49.2.193, https://doi.org/10.1177/001440290507100203, https://doi.org/10.1016/S0005-7894(75)80181-X, https://doi.org/10.1007/s40614-020-00263-x, https://doi.org/10.3758/s13428-011-0111-y, https://doi.org/10.1016/0005-7916(81)90055-0, http://creativecommons.org/licenses/by/4.0/, SI: Commentary on Slocum et al, Threats to Internal Validity. Provided by the Springer Nature SharedIt content-sharing initiative, Over 10 million scientific documents at your fingertips, Not logged in Additional replications further reduce the plausibility of extraneous variables causing change at approximately the same time that the independent variable is applied to each tier. https://doi.org/10.1007/s40614-022-00343-0, SI: Commentary on Slocum et al, Threats to Internal Validity. Two articles published in 1981 described and advocated the use of nonconcurrent multiple baseline designs (Hayes, 1981; Watson & Workman, 1981). WebIn yet a third version of the multiple-baseline design, multiple baselines are established for the same participant but in different settings. Journal of Behavior Therapy & Experimental Psychiatry, 12(3), 257259. It is clear that we cannot claim that these assumptions are always valid for multiple baseline designs. The point is that although the across-tier comparison may reveal a maturation effect, there are also circumstances in which it may fail to do so. The purposes of this article are to (1) thoroughly examine the impact that threats to internal validity can have on concurrent and nonconcurrent multiple baseline designs; (2) describe the critical features of each design type that control for threats to internal validity; and (3) offer recommendations for use and reporting of concurrent and nonconcurrent multiple baseline designs. However, ina concurrent multiple baseline across settings a setting-level event would contact only a single tierthe design would be inherently insensitive to these coincidental events. 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. However, we can never ensure that any two contexts or any two session times are not subject to unique events during the study. He acknowledged that earlier authors had stated that multiple baselines must be concurrent and he noted that in a nonconcurrent multiple baseline the across-tier comparison could not reveal coincidental events. 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 This comparison can reveal the influence of an extraneous variable only if it causes a change in several tiers at about the same time. 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 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. Oxford University Press. The author has no known conflicts of interest to disclose. in their classic 1968 article that defined applied behavior analysis. https://doi.org/10.1037/0022-006X.49.2.193. 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. With stable data, the range within which future data points will fall is To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The assumption that all tiers respond similarly to maturation may be somewhat more problematic. 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 withdrawal phase of an A-B-A design is important because it shows that the results of the intervention weren't just a result of a difference in time. However, it does not rule out maturation as an alternative explanation of the change in behavior. WebIdentify the limitations of multiple baseline design 1.Does not demonstrate experimental control directly 2Provides more information about effectiveness of treatment Multiple baseline designsboth concurrent and nonconcurrentare the predominant experimental design in modern applied behavior analytic research and are increasingly employed in other disciplines. Slocum, T.A., Pinkelman, S.E., Joslyn, P.R. 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. Advantages and Disadvantages of ABA Design. 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. AB Design. Journal of Consulting & Clinical Psychology, 49(2), 193211. Although publication dates would suggest that Kazdin and Kopel (1975) was published before Hersen and Barlow (1976), Kazdin and Kopel cite Hersen and Barlow, and not the other way around. 66 : Discuss the advantages and disadvantages of using visual inspection of graphs rather than statistics to evaluate the significance of the results. Perspect Behav Sci 45, 647650 (2022). This statement, of course, fails to satisfy the operational desire for a specific number of tiers that accomplishes this function. If an effective treatment were to have a broad impact on multiple tiers, the logic of the design would be to falsely attribute these effects to possible extraneous variables. Concurrent multiple baseline designs are multiple baseline designs in which the tiers are synchronized in real time. Type I errors and power in multiple baseline designs. 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. Nonconcurrent multiple baseline designs, however, do not afford this comparison. Psychological Methods, 17(4), 510550. 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. So, similar to maturation, the across-tier comparison is sometimes able to reveal effects of testing and session experience, but it may fail to do so in some circumstances. 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. Webmultiple baseline (3 forms) 1. across bx 2. across settings, 3. across subjects or groups using 3-5 tiers. That is, session numbers do not necessarily correspond to the same periods of real time across tiers. Therefore, researchers must exercise extreme caution in interpreting and generalizing the results from pre-experimental studies. Perspectives on Behavior Science These variables share the key characteristic that their impact would be expected to accumulate as a function of number of experimental sessions. WebMultiple-Baseline Designs There are two potential problems with the reversal designboth of which have to do with the removal of the treatment. Multiple baseline designs can rigorously control these threats to internal validity. Campbell, D. T., & Stanley, J. C. (1963).
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