Abstract
Special education and related professionals often understand the importance of adhering to intervention procedures (i.e., fidelity), but may be less familiar with concepts of intervention intensity. In some cases, professionals may correctly apply an intervention, but with insufficient intensity. This can result in an intervention failing to produce the expected benefit, which can add to student frustration, lost resources, and teacher burnout. Students with autism spectrum disorder (ASD) often benefit from intensive intervention that contains high rates of opportunities to respond. This article provides an overview of a practical guide for adjusting intervention intensity for students with ASD through a three-step process that includes identifying when to adjust intensity along with three ways to adjust intervention intensity. Additional considerations are included for analyzing student responses for data-based decision-making.
Students with autism spectrum disorder (ASD) often require intensive instruction to meet their behavioral, academic, and communication needs. For example, traditional early intensive behavioral intervention for students with ASD usually includes 15 to 40 hours per week of treatment to produce the expected outcome (Dawson et al., 2010). However, the mere number of hours a child receives services is a crude estimate of intervention intensity because interventions for students with ASD often entail frequent opportunities to respond (OTR) within a specific session length to change countable target behaviors. Other dimensions of intervention intensity (e.g., OTR, session length, frequency) can also impact student outcomes. Thus, professionals who serve students with ASD may need to adjust intervention intensity when their students are not making adequate progress.
Professionals understand that an intervention needs to be applied with high fidelity to produce an expected outcome. Fidelity refers to the consistent adherence to intervention procedures (DiGennaro & Codding, 2014). Sometimes, a student might not respond to an intervention because the procedures are not properly followed. However, in some cases, high fidelity to an intervention might not result in the expected outcome due to an insufficient intervention intensity. For example, research indicates that social skills training is generally effective for improving the social skills of students with ASD. However, professionals may follow social skills training procedures with high fidelity, but obtain less than acceptable student outcomes because the intervention was not applied with sufficient intensity. Research may not make clear how much social skills training is needed to produce the expected benefit; likewise, individual student differences (e.g., strengths, weaknesses, preferences, and interests) influence the amount of intervention needed to achieve the outcome. This leaves teachers guessing about how much and how often they need to use the intervention (Codding & Lane, 2015). This may cause teachers to abandon an intervention that would be effective if implemented with sufficient intensity. A related concern is that special educators who believe that they are ineffective may experience persistent frustration and abandon the profession (Zee & Koomen, 2016). Conversely, if professionals who serve students with ASD recognize the importance of and methods for adjusting intervention intensity, they may improve learning outcomes for their students (Stevenson & Reed, 2017) and experience a higher sense of self-efficacy for themselves (Strong, 2014).
Intervention Intensity
Researchers have conceptualized intervention intensity in different ways (Codding & Lane, 2015; Fuchs et al., 2017; Warren et al., 2007; Yoder & Woynaroski, 2015). Warren et al. (2007) provided a straightforward explanation that special educators who serve students with ASD should find helpful. They explained that intervention intensity included (a) dose, (b) dose frequency, and (c) dose duration. According to Warren et al. (2007), the intervention dose refers to the number of OTRs during a single teaching session. Warren et al. also explained that dose frequency was the number of teaching sessions per day or week, and that dose duration was the length of the intervention in days or weeks. For example, a professional might apply a math fact recall intervention with 40 OTRs during a 10-min session (i.e., dose) for five sessions per week (i.e., dose frequency), for four consecutive weeks (i.e., dose duration). Similarly, a “lunch bunch” social skills intervention may require 10 OTRs to peer questions during a 20-min lunchtime session (i.e., dose) 3 days per week (i.e., dose frequency) for 9 weeks (i.e., dose duration). Also, instruction aimed at improving meal preparation skills may require completing a 10-min chain of 15 tasks (i.e., dose) two times per day every school day (i.e., dose frequency) for 2 weeks (i.e., dose duration) to master the tasks. Professionals should plan and deliver instruction based on a general estimate of the total amount of intervention (i.e., intensity) needed to produce the expected outcome.
Data to Inform Decision-Making
Traditionally, when intervention data indicate a student is not sufficiently improving, professionals might supplement the current intervention with an additional intervention. For example, data might indicate a student with ASD continued to get out of seat and leave the classroom despite a visual support intervention. The professional may decide to supplement the visual support intervention with a token reinforcement plan to increase duration of seated behavior. However, this addition may increase the intervention complexity, making it difficult to implement (Pellecchia et al., 2015) and leading professionals to prematurely abandoning the original intervention for a new one (e.g., terminating the visual supports and instead applying a self-monitoring intervention). Changing interventions may also require additional training and resources and may delay student progress (Stahmer et al., 2015). Supplementing and substituting interventions are viable professional strategies, but may not be necessary if data suggest that low student response can be explained by insufficient intervention intensity. Accordingly, professionals may be more efficient when they make systematic adjustments to intervention intensity according to the data before supplementing or substituting an intervention.
This article provides guidance regarding intervention intensity for special education and related professionals who serve students with ASD. Professionals who can systematically adjust intervention intensity may improve student outcomes and experience higher rates of self-efficacy for themselves. A three-step process for adjusting intervention intensity along with suggestions for measuring student responding and making data-based decisions are provided. The process for incorporating adjustments to intervention intensity when planning and delivering specialized instruction is shown in Figure 1. The process begins by evaluating current intervention intensity (i.e., dose, dose frequency, and duration). Next, professionals should increase intervention intensity using one or more techniques. Finally, professionals should rely on data-based decision-making to evaluate the effects of adjusted intensity. Each of these steps is described in further detail.
Decision tree for three-step process for adjusting intervention intensity.
Three-Step Process for Adjusting Intervention Intensity
Step 1: Evaluate Effectiveness of Current Intensity
Professionals should examine their data to decide whether their student with ASD is sufficiently responsive to the current intervention (Filderman & Toste, 2018). Figure 2 is a line graph of data indicating the student is not making adequate progress (for guidance on progress monitoring, see Filderman et al., 2019; McArthur Capizzi & Barton-Arwood, 2009). Professionals should first determine whether the intervention has been applied with high fidelity (see Step 1 in Figure 1). Incorrect implementation of the intervention procedures, either by adding or omitting intervention steps, can negatively alter intervention effects. If the data indicate inadequate progress is due to low intervention fidelity, then professionals should probably continue the intervention and focus on increasing fidelity. If fidelity is high, professionals should seek evidence that other potential factors are interfering with responsiveness (e.g., frequent absences, frequency and intensity of disruptive behavior, limited functional value of skills being taught, insufficient reinforcement). If fidelity is satisfactory and no other factors appear to explain why the student is not making adequate progress, then professionals should collect intensity data.
Graph representing inadequate response to intervention with normal intensity.
Collect intensity data
To determine whether insufficient intensity likely explains inadequate progress, professionals should collect information about the number of OTRs per session, session length, number of sessions per week, and the date the intervention began. This information will be useful for making decisions about how to intensify the intervention. There are several ways to collect intensity data.
Finding the sum of correct, incorrect, and non-responses can reveal the total number of OTRs per session (Cooper et al., 2019). This can be accomplished with tally marks, golf counters, or other methods to document the number of OTRs per session. However, counting OTRs may be difficult when also tracking error types or during procedurally complex instructional interventions. If counting correct and incorrect responses is challenging, then professionals might sample a portion of their instruction to estimate OTRs per session. For example, the teacher might track OTRs during 5 min of a 20-min teaching session and multiply to obtain an approximation.
In addition, a smartphone can be used to audio or video record a session and later listen/watch the recording to count the OTRs (Morin et al., 2019). This method helps professionals focus more on their teaching during instruction and more accurately collect intensity data because they can replay the audio/video multiple times. Audio/video can also capture student responding for progress monitoring. An additional suggestion might include asking a paraprofessional, fellow teacher, or administrator familiar with the intervention to observe and count OTRs during the session (Lane et al., 2004). Finally, professionals who use scripted curricula that make explicit all OTRs need only to count them prior to or following the session (Ganz & Flores, 2009).
Strategic alterations can be made to intervention intensity by collecting data about the number of OTRs per session, number of sessions per day (or week), and the number of weeks an intervention is used (Yoder & Woynaroski, 2015). If data indicate the student is not sufficiently responding to the intervention despite high fidelity of intervention implementation, and student factors do not appear to explain inadequate progression, then increasing intervention intensity should be considered.
Step 2: Increase Intervention Intensity
There are at least three ways professionals can increase intervention intensity: (a) increase the pace of instruction, allowing more OTRs in the same amount of time; (b) increase session length and therefore increase number of OTRs per session; and (c) increase the number of sessions per day or week to add more OTRs. Each of these approaches is described in more detail along with considerations to inform decision-making.
Increase pace of instruction
The pace of instruction can be increased to include more OTRs per session. This can be achieved by increasing the pace of teacher cues or instructions, prompts, and feedback. Although professionals may have some reservations about increasing the pace of instruction (i.e., perhaps due to concerns about mental processing ability), research indicates that rapid instructional pacing may produce superior academic, social, and behavioral outcomes for students with ASD or other developmental disabilities when compared with slower paced instruction of the same content (Julien & Reichle, 2016; Tincani & De Mers, 2016). Researchers have also found that increased instructional pace can increase engagement of students with ASD during classroom activities and instruction (Menzies et al., 2017; Skibo et al., 2011).
Increasing the pace of instruction entails reducing time delay, reducing feedback latency, and/or reducing inter-trial intervals (see Figure 3). More specifically, professionals can reduce the time between teacher’s cue/direction and prompted student responses (Lamella & Tincani, 2012). Educators also can reduce the time between a student’s response and the teacher’s feedback (i.e., feedback latency). They also can reduce the time between feedback and the beginning of the next instructional trial (Cariveau et al., 2016). For example, professionals can intensify an intervention by (a) reducing time delay from 7 to 3 s, (b) reducing feedback latency from 5 to 1 s, and (c) reducing the inter-trial interval from 3 to 1 s.
Model for increasing the pace of instruction to intensify intervention.
Instructional pacing is probably not a viable option when the task requires a student with ASD to complete multiple steps in a predetermined sequence. For example, professionals might only have one OTR for meal preparation during the session because the process includes steps like gathering ingredients, chopping vegetables, turning on the stove, and so on. Increasing the pace of instruction may result in more errors, impede progress, and increase the risk for harm. Also, meal preparation and other similarly chained tasks often do not allow for repeated practice without incurring extra costs for materials, time, and other resources. In cases where increased pace of instruction is not feasible, professionals might instead increase session length and/or session frequency.
Increase session length
A second way to increase intervention intensity is to lengthen intervention sessions while maintaining the original pace of instruction. This is a rather straightforward way of increasing the amount of intervention a student receives (i.e., assuming the pace of instruction is maintained throughout the session). For example, increasing the length of the social skills intervention example (described previously) from 20 to 40 min will likely double the number of opportunities for peer interactions during the session. Special educators might request permission for a short-term increase in session length to evaluate whether this change results in positive student responding. If data indicate more time is needed for specialized instruction, then the team should revise the individualized education program (IEP) to reflect the change. This also may be necessary when professionals examine whether increasing the number of sessions per day or week results in desired improvements to student responding.
Increase sessions per day or week
A third way to intensify an intervention is by increasing the number of sessions per day or week (i.e., dose frequency). This again is a rather straightforward process that entails adding one or more sessions per day or week and is ideal when the pace of instruction and session length feasibly cannot be increased. For example, a reading specialist likely cannot increase the pace of instruction and may not be able to increase session length due to curricular or logistical constraints. In this and similar situations, the dose frequency can be increased from two to four sessions per week. A special education teacher focused on adaptive skills can increase OTRs for meal preparation by scheduling daily rather than weekly sessions. Higher dose frequency provides more opportunities for students to practice the skills, which may result in more timely goal attainment (Yoder et al., 2014).
Considerations for increasing intensity
The decision about which aspects of intervention intensity to adjust depends on the circumstances confronting the professional (see Step 2 in Figure 1). Professionals can choose to maximize intensity by simultaneously increasing pace of instruction, session length, and number of sessions per week (or month) for a short period of time. Maximizing intensity will more immediately reveal whether the intervention should be supplemented or replaced with a different practice. For example, a professional might increase the pace of instruction from 20 OTRs per 15-min session to 30 OTRs per 20-min session. In conjunction, they may increase the number of sessions per week from two to four sessions. This represents an increase from 40 OTRs per week to 120 per week. This significant change illustrates how increased instructional pace, session length, and sessions per week can dramatically intensify the intervention. If maximized intensity is not accompanied by dramatic changes in student responding consistent with expectations as reflected by the graphed goal line, or another way to adjust intensity is not available, then professionals should replace or supplement the intervention with a different evidence-based practice (EBP; see Step 2 in Figure 1).
However, scheduling issues and other responsibilities might prevent professionals from maximizing intervention intensity. In this case, professionals should choose aspect(s) of intervention intensity to increase based on feasibility. Some professionals might focus on adjusting the pace of instruction because increasing session length or adding more sessions per week is not feasible. In other circumstances, it may be difficult to adjust the pace of instruction (e.g., a reading fluency intervention or math fact recall intervention may already be sufficiently rapid). Accordingly, the professional may choose to increase session length or add more sessions per week. Whatever the case, duration of the intervention may need to be extended when only one aspect of intensity is adjusted.
After deciding which aspects of intervention intensity to increase, professionals should determine the level of increase. Currently, there is little information regarding the optimal intensity of each EBP for students with ASD, and differences in contexts and learner profiles will likely influence the decision. For example, scheduling issues and lack of personnel resources may make it impossible to significantly increase dose frequency for social skills training and only allow adding one additional session per week. Similarly, a student who requires a longer responding time probably needs only a small increase in the pace of instruction. Therefore, adjusting the level of intensity is a case-by-case decision-making process. Professionals should take into account individual differences and increase the intervention intensity to the highest feasible level.
Step 3: Monitoring and Data-Based Decisions
Professionals will need to continue collecting and graphing data to determine whether increased intensity is improving student outcomes (see Figure 1). A good indicator is the trend line that represents the overall student progress and future data trajectory. Researchers have developed several methods for drawing trend lines (Cooper et al., 2019), but one easy method is to find the median or mean of the first three data points and plot it on the graph, then do the same for the final three data points. These two plotted points can be connected to create a line representing the trend. Professionals who would like to use a more precise method for calculating the trend may refer to the website for the National Center on Response to Intervention (NCRTI, 2012).
Intensifying interventions will require continual monitoring of (a) procedural fidelity, (b) the emergence of factors that may interfere with responding (e.g., absences, problem behavior), and (c) whether the intervention was actually intensified (e.g., more OTRs per session, intervention sessions per day/week, total weeks). If a high-fidelity and intensified intervention does not generate the expected benefit, and other factors that might reduce responding are not evident, then supplementing or abandoning the intervention should be considered.
Different types of data patterns may emerge after intensifying the intervention. The first pattern entails an immediate increase in responding demonstrated by a steep trend line that quickly exceeds the goal line. These data indicate that the intensified intervention should be continued until the goal is met. The second data pattern corresponds to a gradual increase in responding and is shown by a flatter trend line. This graph shows how increases in intervention intensity may still result in a timely goal attainment when initial progress is limited. In both cases, professionals can conclude that insufficient intervention intensity explained previous poor responding. In other cases, however, data may indicate the student will meet the goal after the intervention was intensified but with more time than originally anticipated being necessary. For example, a student with ASD who was expected to master recollection of math facts in 4 weeks may need one or two more weeks of intensified instruction to meet the goal. Similarly, a student who was expected to learn to prepare 30 meals over a 12-month period might need two more months to learn three more meals to meet the goal. In these and similar situations, data may indicate performance that closely approximated the goal line, and professionals may conclude that changing the intervention to meet the timeline is probably too costly and unlikely to make a meaningful difference when compared to the existing intervention. If, however, early data clearly indicate the goal will not be met in an acceptable time frame, then professionals should change their instruction such that their students receive educational benefit.
Finally, professionals may find a data pattern that shows no noticeable increase in the trend of responding after intensifying their intervention (i.e., the trend line is almost parallel to that in the previous session). This pattern implies previous poor responding is not due to insufficient intervention intensity. Accordingly, professionals should abandon the intervention and select a different EBP for learners with ASD.
Conclusion
Intervention intensity is an important aspect of specialized education that includes dose, dose frequency, and dose duration. Sometimes an EBP for learners with ASD may not produce the expected effect despite high fidelity of implementation. Before supplementing or substituting their intervention, professionals should consider increasing the intensity in one or more ways. They may maximize intervention intensity by increasing the pace of instruction, extending session length, and adding more sessions per day or week. Maximized intensity permits quick determinations about whether the intervention should be supplemented or replaced with a different EBP. Alternatively, professionals may choose to make adjustments to intervention intensity and observe whether improved responding will lead to the goal being met on time. In either case, special education professionals who serve students with ASD should regard collecting and analyzing student response data as well as procedural fidelity and intervention intensity data as critical aspects of their decision-making.
Footnotes
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
