Assessing Skill Strengths in Individuals with Autism and Other Developmental Disabilities: Practical Considerations for Behavior Analysts

Headnote

Abstract : The BCBA Task List (5" and 6" Edition) requires behavior analysts are familiar with multiple assessment methods, including tools to assess the function of problem behaviors and assess skill strengths and deficits. Although several studies exist on the assessment of functions using indirect functional assessments, descriptive functional assessments, and functional analyses, there is no comprehensive review and/or description of skill-based assessments used by behavior analysts. Based on literature and clinical practice, the current paper describes several skill-based assessments, including key features of the assessment, reliability and validity, and consideration for behavior analysts in their practice. Implications for practice and research are discussed.

Keywords: assessment; behavior analysts; practice; skill deficits; skill strengths

The Behavior Analyst Certification Board (BACB®) 5th Edition Task List under the Behavior Assessment content area requires behavior analysts be competent in conducting assessments of relevant skill strengths and deficits (BACB, 2017; F-4 & E-3). Also, the Ethics Code for Behavior Analysts (E-3; Assessing behavior) and the Personnel Supervision and Management (I-4; Train personnel to competently perform assessments and intervention procedures) areas require behavior analysts to be competent in all assessment procedures.

To assess clients, behavior analysts and their supervisees must be aware of options for behaviorally-based assessments when developing intervention plans. Further, the current BACB guidelines state behavior analysts should select and design assessments that use behavioral principles, are evidence-based, and meet diverse needs of clients (Ethics code 2.13; BACB, 2022). Researchers also emphasized behavior intervention goals should be derived from assessments to effectively target an individual's skill deficits (Padilla et al., 2023).

Correspondence concerning this article should be addressed to: Devender Banda, College of Education, Texas Tech University, 3002 18% St, Lubbock, TX 79409. Email: [email protected] Educators use several types of assessments, including standardized tests, curriculum-based measures (CBM), and criterion-based assessments. Standardized assessments follow a set of procedures for administration and scoring. They provide norm-referenced scores to compare the student to a large sample population for whom the test is designed (Cooper et al., 2020). These tests typically are administered by licensed school psychologists or clinical psychologists. Results from standardized assessments cannot provide sufficient information or create interventions for target behaviors (Cooper et al., 2020). However, they provide a broader understanding of student skills for program planning. CBMs are a systematic data collection procedure to obtain skill levels in basic areas of achievement (Cusumano, 2007). Data gathered from CBM provide a general overview of skill acquisition and fluency.

CBMs can be used to periodically monitor skills to determine the impact of instruction, intervention, or program implementation (Cusumano, 2007). Criterion-based assessments measure performance against accepted developmental milestones (Cooper et al., 2020). For behavior analysts, criterionbased or curriculum-based assessments provide strengths and weaknesses in each skill area they assess so specific skills can be targeted for change.

Behavior analysts should be aware of two important properties of assessment-reliability and validity. Reliability refers to "the desired consistency (or reproducibility) of test scores" (Crocker & Algina, 2008, р. 105). In other words, when the assessment is administered on multiple occasions, the results should be close enough to rule out external factors. Reliable assessments should give an accurate measure of the client's performance and produce stable and consistent results. There are three types of reliability: testretest (i.e., similar scores across subsequent administration of the same test),

alternate form (ie, a similar parallel test is administered and compared to the original test to see if the scores are similar across tests), and internal consistency (i.e., how closely the individual items are related to each other). In general, assessments that show reliability of +.80 (80%) or higher should be selected.

Tests should also be valid. A valid test measures what it intends to measure. For example, when assessing a language component, the test should measure language rather than cognitive ability or a personality trait. Cooper et al. (2020) noted three important elements of validity: directly measuring socially significant target behavior, measuring a dimension (e.g., duration, frequency) of the relevant target behavior, and ensuring the collected data is representative of the behavior's occurrence under the conditions relevant to the behavior.

Behavior analysts should be aware of four types of validity when reviewing or using the tests: face validity, construct validity, criterion validity, and content validity. Face validity is a basic form of validity to see if the assessment measures the construct of interest. For example, if the assessment is intended to measure social skills, does it appear to measure social skills? However, face validity is a very weak measure and can be subjective. Construct validity is how accurately the test measures the concept. For example, if the test claims to measure social skills, it should measure social skills constructs (several individual components of social skill such as initiations,

responses, and non-verbal skills, which form a complex social construct). Criterion validity refers "to the degree to which a test score is related to a meaningful outcome or criterion of interest" (Horstmann et al., 2019). Criterion validity evaluates how well a test can assess the current state of the participant level or performance (i.e., concurrent validity) and is able to predict an outcome (i.e., predictive validity). Content validity should involve all components of a construct. For example, a communication assessment should include an entire range of both receptive and expressive communication items (for detailed descriptions of reliability and validity components of assessment, refer to Padilla et al., 2023).

Beyond those four measures of validity, social validity (i.e., consumer satisfaction or consumer acceptability) of skill-based assessments must be taken into consideration. Kennedy (1992) described asking subjects or relevant stakeholders the most important behavior needing to be changed before the behavior intervention is introduced and whether the target behavior changed after the intervention is implemented.

For skill-based assessments, social validity is important because assessors as well as stakeholders should think the assessment identifies relevant treatment goals, is administered in an acceptable fashion, and is cost-efficient. In applied behavior analysis (ABA), measurement must be valid and reliable to be trustworthy (Cooper et al., 2020).

Researchers have conducted several literature reviews on assessments used in ABA.

Gould et al. (2011) conducted a comprehensive review of assessments used in early intensive behavioral interventions curriculum programs addressing a wide range of domains: developmental/educational, social skills, motor function, speech/language communication, daily living, play skills, academic/achievement, and intelligence. The authors noted assessments in some domains are typically administered during the diagnosis process (e.g., developmental, intelligence, academic achievement) by school psychologists, speech language pathologists, and educational diagnosticians. When working with individuals with autism and other developmental disabilities, behavior analysts may want to conduct additional assessments in the domains of social skills, communication, and adaptive behavior. Gould et al. noted the following early intervention service assessments useful for behavior analysts: communication (e.g., Assessment of Basic Language and Learning SkillsRevised, ABLLSR; Partington, 2010); Verbal Behavior Milestones Assessment and Placement Program, VB-MAPP; Sundberg, 2014),

daily living skills (e.g., Vineland Adaptive

Behavior Scales-3, VABS; Sparrow et al., 2016), social skills (e.g., Social Skills Rating System; Gresham & Elliot, 1990).

Bolte and Diehl (2013) conducted a literature review of autism interventions from 195 articles conducted between 2001 to 2010 and found 289 measurement tools ranging from informal to formal assessments. The authors analyzed the quality and distribution of target skills/symptoms covered by the measurement tools in three areas: psychological (interventions targeted to modify cognition and behavior), pharmacological, and complementary/ alternative medicine. The investigators found the most commonly used measurement/observation tools in psychological area were VABS (Sparrow et al., 2016), Bayley's Scale of Infant and Toddler Development (Bayley, 2006), and videotaped observations designed by investigators. The authors did not recommend skill-based assessments to address behaviors in individuals with autism spectrum disorders, noting many of these assessments were not sensitive to small changes, which may not be useful for behavior analysts who rely on continuous data collection and measurement during interventions.

Similarly, Hanratty et al. (2015) conducted a systematic review of behavior measurement tools used in published studies prior to 2013 (randomized and quasi-randomized) in young children (birth to 6 years) with autism spectrum disorders. The authors listed 12 measurement tools, including the Aberrant Behavior Checklist (ABC; Aman et al., 1985), the Behavior Assessment System for Children (BASC-2; Kamphaus & Reynolds, 2007), and the Child Behavior Checklist (CBCL; Achenbach, 1999). They concluded a lack of research exists on psychometric properties for several assessments. Also, many scales lack sensitivity to minor behavioral changes, making it difficult to evaluate treatment effects on a regular basis to make clinical decisions about when to continue, modify, or discontinue the intervention.

Ackley et al. (2019) examined 18 ABA-based assessments and curricula used to teach communication skills in children with autism. The authors mentioned only four protocols had appropriate reliability and validity data (ABLLS-R; Promoting the Emergence of Advance Knowledge Relational Training System, PEAK; Dixon, 2014; Skills for Autism, SKILLS; Skills Global, 2017; VB-MAPP), and four other protocols had effectiveness data (Autism Curriculum Encyclopedia, ACE; New England Center for Children, 2013; Early Start Denver Model for Young Children with Autism, ESDM; Rogers & Dawson, 2010; PEAK; Strategies for Teaching Based on Autism Research, STAR; Arick et al., 2004). Many of the protocols incorporated individual researchbased ABA strategies (e.g., reinforcement, prompting) but little research exists on the effectiveness of the intervention packages offered in various protocols. Researchers concluded many of the tools lacked research on psychometric properties such as reliability and validity. The authors recommended future researchers investigate the utility and effectiveness of commonly used ABA-based protocols for skill building in individuals with autism.

Recently, Padilla et al. (2023) conducted a systematic review to examine the reliability and validity of commonly used criterion referenced assessments in ABA. They analyzed six assessments (e.g., Assessment of Basic Learning Abilities, ABLA; Kerr et al, 1977; ABLLS-R; PEAK; Verbal Behavior Assessment Scale; Duker, 1999; the Training and Assessment of Relational Precursors and Abilities, TARPA; Moran et al., 2010; VB-MAPP; SKILLS) from 46 studies. Only 37 of 46 studies presented reliability data, and 43 of 36 presented validity data. The investigators found a mismatch between the use of assessments and their research base. For example, VB-MAPP is the most commonly used assessment but only has two studies reported reliability and validity.

Furthermore, ABLA and PEAK have multiple studies establishing reliability and validity but are used infrequently by ABA practitioners. The authors concluded multiple studies should be conducted on each ABA assessment to establish reliability and validity by collaborating with measurement experts (e.g., psychometrician, statistician). Additionally, ABA practitioners need to have familiarity with basic psychometric properties in order to select and use the assessments with a sound research base in their practice. According to Padilla et al. (2023), "The strength of reliability and validity evidence is an important factor when selecting assessments for practice, research, or insurance policies, but it must also be aligned with the code of ethics and dimensions central to the work of behavior analysts" (р. 281).

Researchers have conducted only one survey on the use of assessments by ABA professionals. Padilla (2020) surveyed 1,428 ABA professionals (i.e., clinical supervisors, faculty members, graduate students, and practitioners) to identify commonly used assessments by ABA practitioners. The researchers found VB-MAPP was most often used by the respondents (76%), followed by ABLLS-R (45%), VABS-2 (34%), and PEAK (14%). Survey respondents (35%) reported using 115 different assessments in addition to the four assessments researchers surveyed. The authors also reported 71% of respondents received assessment training from their direct supervisors. Respondents selected assessments based on research literature (58%), insurance requirements (38%), or colleague recommendation (38%). Despite the fact respondents identified "research literature" as the basis for selecting assessments, there is little research on the psychometric properties of the assessments, particularly for VB-MAPP. The authors recommend more research on reliability and validity of assessments used in the field of ABA.

Although several reviews and surveys have been conducted on ABA skill-based assessments, no single review has addressed effectiveness, usability, reliability, and validity across the life span. Furthermore, previous literature does not provide general guidelines for practicing behavior analysts. Therefore, the purpose of this article is to inform behavior analysists about the range of tools for assessing skill strengths and areas of need (deficits) that are used or available for use in the field.

Method

To determine which assessments should be included in this paper, we consulted literature, including systematic reviews and surveys, to identify ABA skill-based assessments that are research-based. First, we identified assessment tools used in surveys (Padilla, 2020) and systematic reviews used by behavior analysts and practitioners in the field of autism and other developmental disabilities (Ackley et al., 2019; Bolte & Diehl, 2013; Gould et al., 2011; Hanratty et al., 2015; Padilla et al., 2023). Second, from the surveys and reviews, we identified tools assessing individual skill strengths and deficits. Third, we prioritized assessments reported in the literature as being commonly us ed for intervention planning as well as for research purposes in the field. We did not include: a) function-based assessments (e.g., Motivational Assessment Scale, MAS; Durand & Crimmins; 1988; Functional Assessment Interview, FAI; O'Neill et al, 2015; Functional Assessment Screen Tool, FAST; Iwata & DeLeon, 2005); b) intelligence or diagnostic assessments (e.g., Stanford-Binet Intelligence Scales; Roid & Pomplun, 2012; Wechsler Intelligence Scale for Children Fifth Edition, WISC; Wechsler, 2014; Woodcock-Johnson Test of Cognitive Abilities; Woodcock et al., 2001; Autism Diagnostic Observation Schedule, ADOS; Lord et al., 1999); or с) standardized language assessments (e.g., Clinical Evaluation of Language Fundamentals, CELF-R; Semel et al., 2003; Preschool Language Scale, fourth edition, PLS4; Zimmerman et al., 2002) typically administered by speech language pathologists. We excluded the afore-mentioned assessments because they were not included in any of the systematic reviews or surveys on skillbased assessments.

Based on these criteria, the following assessments are reviewed: VB-MAPP, ABLLS-R, VABS3, Social Skills Improvement System (SSIS; Gresham & Elliot, 2008), PEAK, ABLA, the Assessment of Functional Living Skills (AFLS; Partington & Mueller, 2015), and Essential for Living (McGreevy et al., 2012). Though VABS3 3 a standardized assessment, we included it because it is often reported in the literature and is also used by practitioners in intervention planning. For each assessment, we described the purpose, age range, domains, administration time, reliability, validity (if available), and considerations for behavior analysts (see Table 1). We categorized the reliability and validity component based on the number of studies reported in the literature. We labeled the assessments as "weak" for no studies, "emerging" for few studies, "strong" for multiple studies, and "very strong" for numerous studies.

Assessments

Verbal Behavior Milestones Assessment and Placement Program (VB-MAPP)

Sundberg (2008; 2014) developed the VBMAPP based on Skinner's analysis of verbal

162 / Education and Training in Autism and Developmental Disabilities-June 2025

TABLE 1

Skill-based assessments in ABA

Assessment

Age Range

Type (Rating Scale, Interview, Observation)

Domains/ Target Skills

Time to Administer

Reliability and Validity

Reported use in Practice"

VB-MAPP (Sundberg, 2008; 2014)

ABLLS-R (Partington, 2010)

VABS-3 (Sparrow et al., 2016)

SSIS (Gresham & Elliott, 1990; 2008)

PEAK (Dixon, 2014)

AFLS (Partington & Mueller, 2015)

0-4 years

0-12 years

0-90 years

3-18 years

18 months18 years

Across life span

Observation

Rating & Observation

Rating Scale

Rating Scale

Rating & Observation

Interview & Observation

Social, Motor, Language, Play, & Academic

Language, Social Interaction, Academic, Self-help, Motor Skills

Communication, Daily Living, Socialization, Motor, Adaptive Behavior

Social Skills, Problem Behaviors, Academic Competence

Direct Training, Generalization, Equivalence, Transformation

Basic Living, Home Skills, Community Participation Skills, School Skills, Independent Living Skills, Vocational Skills

3-10 hours

3-10 hours

20-90 minutes

10-20 minutes

2 hours

60-90 minutes

Emerging (few studies)

Emerging (few studies)

Very strong (numerous studies)

Very strong (numerous studies)

Strong (multiple

studies)

Weak (no studies)

Assessment and program planning

Assessment and program planning

Diagnosis of IDD and program planning

Assessment and program planning

Assessment and program planning

Assessment and program planning

(continued on next page)

operants (e.g., choices, mands, tacts, and intraverbals). This is a criterion-referenced tool and comes with a curriculum guide and a skill tracking system for children with autism and other developmental disabilities. The VB-MAPP covers five skill areas, including social, motor, language, play, and academic skills, for children between the ages birth to 4 years. The VB-MAPP consists of five subscales: VB-MAPP Milestones Assessment (assesses a child's verbal language and related skills), VB-MAPP Barriers Assessment (assesses common learning and language acquisition barriers among children with autism and other developmental disabilities), VB-MAPP Transition Assessment (assists the IEP team in progress monitoring and placement in least restrictive educational environment), VB-MAPP Task Analysis and Supporting Skills (advanced breakdown of supporting skills of previous subscales), and VB-MAPPP Placement and IEP Goals (assists the team with program planning by including several components of intervention). Sample items in Manding area include "Mands 10 different adjectives, prepositions, or adverbs." The responses typically include whether they are present with "Yes" or "No." Some areas can include prompted and unprompted responses. VB-MAPP can be administered in a variety of settings, including home, school, or clinic. The assessment can take anywhere from 3 to 10 hours to administer depending on the child's age and skill level.

Reliability and Validity. There have been a few studies that reported reliability and validity of VB-MAPP. Montallana et al. (2019) reported VB-MAPP had good reliability (.80) for the Milestones and moderate reliability for Barrier Domain (.60). Also, the authors reported there were issues with reliability of individual domains, which highly varied. Some studies have reported interobserver agreement (Barnes et al., 2014) and content validity (Dixon et al., 2015) for VB-MAPP. In a survey with 13 content experts, Padilla and Akers (2021) evaluated the content validity of VB-MAPP; they reported the Early Echoic Skills Assessment (EESA) and Barriers Assessment domains had moderate to strong content validity within evaluated areas, but not across areas, which may underestimate an individual's skill level. Furthermore, results show VB-MAPP was relevant to

target behavior but may not represent constructs for all domains. The authors recommend using multiple assessments to measure the same or related skills to build a robust treatment plan (Padilla & Akers, 2021). Based on the literature, we consider VB-MAPP to have "emerging" data on reliability and validity.

Considerations for Behavior Analysts. According to Padilla et al. (2023), the VB-MAPP was the most widely used criterion referenced assessment with 76% of participants in their systematic review. The VB-MAPP contains charts that allow behavior analysts to view skill strengths and monitor progress. It also contains a placement and IEP goal selection, which might help behavior analysts to target all relevant areas of intervention components a child needs. With training, behavior analysts can easily administer the VB-MAPP and identify specific items needing to be taught and the order they should be taught. Some limitations of the VB-MAPP include the length of time it takes to assess the child on each item (Gould et al., 2011), the potential to underestimate individual skill level, and it may not represent all skills areas (Padilla & Akers, 2021).

The Assessment of Basic Language and Learning Skills- Revised (ABLLS-R)

ABLLS-R (Partington, 2010) is a criterion referenced assessment protocol, curriculum guide, and skill tracking system to assess academic, learning, social, and classroom readiness skills of individuals with autism and other developmental delays or disabilities. The test includes ABLLS-R Protocol, Scoring Instructions, and IEP Development Guide. ABLLS-R is useful to measure expressive language based on Skinner's verbal behavior. ABLLS-R consists of 544 items and 25 skill sets, including language, social interaction, academic, self-help, and motor skills. Learners are rated on a Likert scale on each skill from absent, emerging, to mastered. For example, in the Receptive Language area, items include, "Responding to own name" and "Follow instruction to look at a reinforcing item." The ABLLSR also assesses learner readiness in various classroom settings, including cooperation and reinforcers, group instruction, classroom routines, and generalized responding (Doehring et al., 2008). The age range of this assessment is from birth to 12 years, and it can take from 3 to 10 hours to administer the test. In each area, ABLLSR identifies strengths and weaknesses, establishes baseline level in relation to typical peers, and assists in developing specific treatment or education goals. The administration is done by directly observing the students; some items may require information from parents or caregivers.

Reliability and Validity. Some research has been conducted on its effectiveness, including two studies supporting validity (Malkin et al., 2017; Usry et al., 2018) and three supporting reliability (Partington, 2010; Partington et al., 2018; Usry et al., 2018). Malkin et al. (2017) assessed the criterion validity between the VABS-II, ABLLS-R, and the PEAK Direct Training modules (PEAK-DT) utilizing Pearson correlations. The results indicated a strong positive correlation between PEAK-DT and ABLLS-R scores and moderate correlations between PEAK-DT and VABS-II Adaptive Behavior Composite (ABC) scores. Moderate correlations were also found between scores for VABS-II ABC and ABLLS-R scores. Usry et al. (2018) used two expert panels to evaluate content validity and inter-rater reliability and found 81% of items were "essential" and had excellent inter-rater reliability across ABLLS-R scores. They concluded ABLLS-R is a valid assessment that yields reliable scores (Usry et al., 2018). Similarly, Partington et al. (2018) examined internal consistency reliability (>.90) and test-retest reliability with parents and professionals and reported strong internal consistency reliability and strong testretest correlations at the 3-months mark (.84) but not at the 6-, 9-, and 12-months marks, possibly due to developmental growth. ABLLS-R appears to have "emerging" data on reliability and validity.

Considerations for Behavior Analysts. ABLLS-R is a popular assessment used by clinicians, including behavior analysts, to measure prelanguage and language skills of children with autism (Partington et al., 2018; Usry, 2018). It assesses academic, self-help, and motor skills, making it a comprehensive assessment. For behavior analysts, the ABLLS-R provides

specific areas of learner readiness for classroom settings. ABLLS-R provides a visual reference to track specific skills through a set of grids, which can be very useful for behavior analysts. It allows easy identification of skill deficits and areas requiring intervention.

Also, ABLLS-R includes an IEP guide, which can be very useful for behavior analysts providing services to children with disabilities in school settings. No specific training is required to administer the protocols, which makes it useful for parents, educators, and a wide variety of professionals. However, the assessment is lengthy and may take anywhere from 3 to 10 hours to administer because it uses direct observation and does not provide basal or ceiling guidelines (Doehring et al.,

2008; Pritchard, 2013). Since ABLLS-R only assesses a narrow age range (birth to 12 years), its utility for older or higher functioning students is uncertain.

Vineland Adaptive Behavior Scales-III (VABS-III)

VABS (Sparrow et al., 2016) assesses adaptive behaviors of individuals ages ranging from birth to 90 years. Although VABS is typically used for diagnosis of intellectual disability, it is often used by professionals for developing treatment goals or educational planning. The VABS-3 measures adaptive behavior across many disabilities, including intellectual and developmental disabilities, autism, ADHD, hearing impairment,

and multiple disabilities. VABS has been standardized not only in the U.S. but in many countries across the world. Several areas are assessed in the VABS: communication (receptive, expressive, and written), daily living skills (personal, domestic, and community), socialization (interpersonal relationship, play and leisure, and coping skills),

motor (gross and fine), and adaptive behavior (internalizing and externalizing). VABS-3 consists of three administration formats: teacher version, parent/ caregiver form, and interview form. The teacher form contains the child's behaviors observed during school settings, whereas parent/caregiver form items reflect home and community environments. VABS has a Comprehensive Form with many more items in each area and a briefer Domain assessment (Pepperdine & Mccrimmon, 2018). All domain items or participant behaviors (independent or with

prompting) on VABS are scored on a threepoint Likert scale: 0 (never), 1 (sometimes), and 2 (often). Sample items in VABS in Expressive Subdomain include "Names at least 10 objects," "Says her age when asked," "Names at least 3 actions," etc.

The VABS provides a summary of standardized scores with confidence intervals, and the statistical significance of differences between domains and subdomains. VABS can be administered online or by paper and pencil. The online form automatically administers correct items in correct sequence, while the paper form requires the assessor to monitor items (basal or baseline, ceiling, and age-related start points; Pepperdine & Mccrimmon, 2018). VABS takes anywhere from 20 minutes to 90 minutes to administer. Further more, it is available in Spanish version, making it a viable option when working with bilingual students.

Reliability and Validity. The VABS has high reliability and validity as evidenced in the literature (e.g., de Bildt et al., 2005) and has "very strong" data on these psychometric properties. Vineland manual provides reliability data for standardization sample across several domains ranging from .94 to .98, which is excellent (Sparrow et al., 2016). The manual also provides excellent testretest and interrater reliability. Overall, VABS has strong internal consistency and indicators of validity (see Pepperdine & Mccrimmon, 2018).

Considerations for Behavior Analysts. The VABS-3 is one of the often-used assessments to diagnose intellectual disability and to assess skill deficits in individuals with developmental disabilities. It is a useful and economical tool for both research and clinical work (Pepperdine & Mccrimmon, 2018). For behavior analysts, the VABS provides general strengths and deficits and specific subskills for intervention development. The online version might be useful for behavior analysts to assess the clients remotely. The VABS relies on parent/ teacher knowledge of student performance, and there is no direct observation required to administer the scale. Since behavior analysts rely on direct observations to assess behaviors, VABS may provide less specific information than they could collect through direct observation. Also, this scale is not sensitive to

minute behavioral changes typically assessed and tracked by behavior analysts on a regular basis. For example, at least 6 or more months of gap may be needed to see any changes in skill levels of individuals with autism and other developmental disabilities.

Social Skills Improvement System (SSIS; Gresham & Elliott, 2008)

The SSIS (previously known as Social Skills Rating System [SSRS]; Gresham & Elliott, 1990) is a standardized, norm-referenced socialskills assessment for school-age students 3 to 18 years. SSIS yields standard scores with percentile ranks on a nationwide sample for race, region, and SES. It is also normed for preschool,

combined norms, and separate sex norms. The tool evaluates the individual's social skills, problem behaviors, and academic performance in relation to typically developing peers. In the area of Social Skills, SSIS measures communication, cooperation, assertion, responsibility, empathy, engagement, and self control. The Problem Behavior area includes externalizing behaviors, bullying, hyperactivity/inattention,

internalizing behaviors, and autism spectrum. In the Academic Competence area, which is rated by a teacher, the subcategories include reading, math, motivation, parental support, and general cognitive functioning. SSIS contains an assessment, intervention guide, and a class-wide intervention guide. The SSIS consists of three ratingstyle forms for teachers, students, and parents and is available both in English and Spanish.

On the Parent and Teacher Forms, the items are rated on a four-point Likert scale on the frequency of occurrence of social skills and inappropriate behaviors ranging from Never, Seldom, Often, to Almost Always. Items examples from the Social Skills area include "Makes friends easily,"

"Says please," "Asks for help from adults," etc. The assessment only takes 10 to 20 minutes to administer. The forms can be paper and pencil scored or computer scored.

Reliability and Validity. The SSIS, particularly the previous version of the scale (i.e., SSRS) has a "strong" research base on reliability and validity. Gresham et al. (2011) found high reliability and validity between SSRS and SSIS across elementary and secondary age groups. Also, studies have shown SSIS has high reliability and validity across special populations groups, such as those with ADHD (Van der Oord et al., 2005) and Down syndrome (Channell et al., 2023), and geographical locations including China, Brazil (Freitas & Del Prette, 2015), and Norway (GamstKlaussen et al., 2016).

Considerations for Behavior Analysts. SSIS is one of the most commonly used assessments to evaluate social skills in individuals with disabilities and in research studies to evaluate the impact of intervention (Crowe et al., 2011). SSIS can be administered within 10 to 20 minutes and an easy to use rating system.

SSIS may be particularly useful for individuals with autism and other developmental disabilities who frequently demonstrate social skill deficits. Though it has a strong research base, the use of SSIS among practicing behavior analysts appears to be limited, according to the surveys and systematic reviews described earlier.

The Promoting the Emergence of Advance Knowledge (PEAK) Relational Training System

The PEAK assessment (Dixon, 2014) is based on Relational Frame Theory (Hayes et al., 2001) and can be used with clients from 18 months to teenage years. The PEAK has four consecutive learning modules: Direct Training, Generalization, Equivalence, and Transformation. PEAK also includes a challenging behavior index. PEAK contains a direct preassessment, a full 184itemized skill assessment, and a 184-item curriculum (Dixon, 2014) intended to be completed by parents or trained professionals (Ackley et al., 2019). PEAK-DT uses positive reinforcement to teach early learning skills, such as making eye contact, attending to the teacher, requesting preferred objects, labeling things in the environment, and early social skills. PEAK Generalization (PEAK-G) teaches learners to use skills in novel settings and applications. PEAK Equivalence (PEAK-E) builds upon the two previous modules to teach advanced symbolic behavior and authentic language beyond a training environment. Learners are encouraged to gain indirect reinforcement and make inferences from observed events in

naturally occurring settings. PEAK Transformation (PEAK-T) targets advanced skills, such as complex cognition, reasoning, and problem solving. Learners are encouraged to compare familiar events to unfamiliar events, using the concepts of compare, contrast, and ranking (Dixon, 2014). PEAK takes less than 2 hours to administer and is conducted in three parts: indirect assessment for parent and teachers (yes/no/ don't know options), brief pre-assessment, and direct testing of items from the PEAK module to identify skills that are or are not in the client's repertoire (Moore et al., 2020). The Likert type rating is used from Never (0), Occasionally (1), Frequently (2) for Challenging Behavior Index.

Examples of PEAK assessment in Receptive area include pictures of three items and a verbal prompt "Where is coconut?" or in the Labeling Functions area "Find the one that cooks food" [oven, printer, spoon].

Reliability and Validity. PEAK has a considerable research base as compared to other skills assessments (Ackley et al., 2019; Moore et al., 2020) and a "strong" evidence of reliability and validity. Multiple studies support the reliability and validity of the first PEAK module, PEAK-DT (e.g., Daar et al., 2015; Dixon, Carmen et al., 2014; Dixon, Whiting et al., 2014, Dixon et al., 2016; Malkin et al., 2017; Rogers & Vismara, 2008). Other studies demonstrated PEAK-DT has validity compared to similar assessments (Dixon et al., 2015; McKeel et al. 2015; Rowsey et al., 2015).

Considerations for Behavior Analysts. PEAK is based on ABA and provides comprehensive resources for program planning. PEAK is not only used for assessment but includes training protocol using strategies such as Discrete Trial Training (DTT) to teach a variety of skills to students. It also includes generalization training component as well. PEAK training modules include many skills from VB-MAPP or ABLLS-R such as requesting, labeling, and imitation.

Therapists who are familiar with VB-MAPP or АВШ УК may be able to use the PEAK modules without much training.

PEAK has some limitations. Despite this sizable research base, additional research is needed to replicate this research with the more advanced PEAK modules (Ackley et al., 2019). Also, PEAK's use in the ABA practice is not widely known, possibly due to the complexity of the assessment. Social validity of the PEAK assessment needs further research.

The Assessment of Functional Living Skills (AFLS)

AFLS (Partington & Mueller, 2015) is an assessment protocol and curriculum guide that includes functional, adaptive, and self-help skills throughout the lifespan (e.g., traveling in the community, making purchases, preparing meals, participating in social and leisure activities). The AFLS covers over 735 daily living skills. The AFLS assesses a range of skills including vocational and daily living skills, community participation, and community interaction for adults with disabilities in various living arrangements (with parents, independent living, group setting).

This criterion-based assessment can be completed by educators or therapists using a combination of direct observation, interviews, and task performance. The assessment package includes an assessment tool, tracking system, and curriculum guide for six domains: Basic Living, Home Skills, Community Participation Skills, School Skills, Independent Living Skills, and Vocational Skills. The scoring is done on Likert scale from 0 (Never), 1 (Sometimes), to 2 (Always). Some of the items on the scale are scored on a 0 to 4 Likert scale. Sample items from Independent Living Skills domain include "Learner will maintain a schedule of activities on a calendar" and "Learner will prepare meal that includes at least three separate food items." AFLS can be customized for each learner to include items or domains relevant to the learner in their current stage and it can take from 60 to 90 minutes to administer.

Reliability and Validity. To our knowledge, no research has been conducted on the reliability and validity of AFLS ("weak" levels of evidence). However, a few studies have used AFLS to assess student performance prior to intervention (e.g. Wheeler et al, 2023). Future research needs to be conducted to evaluate the psychometric properties of AFLS.

Considerations for Behavior Analysts. The AFLS is one of the few assessments that includes all age groups, particularly adults

with disabilities. The assessment can be used by parents, educators, behavior analysts, and caregivers. It is recommended AFLS information be collected from multiple sources to obtain a complete picture of individual skills.

AFLS protocol does not contain a curriculum guide but does encourage assessors to build task analyses to teach target skills. Instructions for assessment specify the rater should describe what the learner typically does. This can overestimate or underestimate skills the learner sometimes or occasionally performs or performs with assistance. Another limitation is the rater may not be able to assess performance for all items and is asked to infer whether the participant can independently demonstrate a skill. Also, the assessor needs to be familiar with the individual,

which can be difficult if the therapist is working remotely or has minimal contact with families. It identifies a general area of deficit (e.g., conversational skills) but does not identify special subskills (e.g., turn taking or commenting). There is limited research on AFLS use, reliability, and validity. The behavior analysts should be cautious about using the AFLS without further research.

Assessment of Basic Learning Abilities (ABLA)

ABLA (Kerr et al., 1977) is used to measure motor, visual, and auditory discrimination skills of persons with disabilities, including autism,

between the ages of 2 to 6 years. During test administration, the assessor uses prompting and reinforcement to assess to what extent an individual is able to perform specific skills. The purpose of the assessment is to evaluate an individual's learning potential for imitation and discrimination skills. ABLA includes six skills levels:

imitation (Level 1), visual discrimination (Levels 2 & 3), identity matching (Level 4), and audiovisual conditional discriminations (Levels 5 and 6). The Imitation Level 1 may include asking the child to put a white foam in a container after the examiner performs the same act. Level 2 Visual Discrimination includes asking the participant to place the white foam in a specific color box, and Level 3 Visual Discrimination task includes further discriminating when the different color boxes are alternated. Level 4 involves more complex discrimination, including asking the participant to put a small red cube in a red box and a yellow cube in a yellow cylinder. ABLA can be used to pinpoint foundational skill deficits in audiovisual conditional discrimination training (e.g., Stubbings & Martin, 1995; Wacker et al., 1983). ABLA takes approximately 30 minutes to administer.

Reliability and Validity. ABLA has "strong" psychometric properties (Rezutek et al., 2021). ABLA has been researched in several studies to demonstrate the reliability and validity of the various levels in the assessment protocol (Conyers et al., 2002; Reyer & Sturmey, 2006; Stewart et al., 2010). For detailed review of ABLA, see Martin et al. (2008), which found ABLA has predictive validity across various types of imitation and discrimination studies for adults and children with and without developmental disabilities.

Considerations for Behavior Analysts. ABLA is useful for predicting formation of equivalent classes and language, which can be used to plan programming for educational and vocational activities (Stewart et al., 2010). Also, ABLA assesses an individual's discrimination skills, which may increase the accuracy of preference and choice assessments (Conyers et al., 2002). ABLA is a highly technical assessment with a lengthy administration time and therefore may not be useful in classroom settings. Also, ABLA requires adequate motor skills to manipulate objects and may not be suitable for persons with multiple disabilities (Rezutek et al., 2021). After a flurry of research in the early and late 2000s, we are unsure how often the ABLA is currently being used by behavior analysts in their practice.

Essential for Living (EFL) Curriculum

McGreevy et al. (2012) built the assessment based on Skinner's analysis of verbal behavior. It is an assessment and curriculum designed for children and adults with moderate to severe disabilities. The EFL assessment results are used to develop IEP goals. The assessment includes present level of functioning for each domain: Speaking and Listening (requests, related listener responses; listener responses, names and descriptions; answers to questions

and conversations), Doing (daily living and related activities, functional academic skills), Tolerating (tolerating skills and eggshells), and Inappropriate Behaviors. The skills categorized as "must have," "should have," "good to have," and "nice to have." For example, the "must have" skills include "Remains in line when directed" and "Waits at current location." The "should have" skills include "Clean up after making a mess" and "Provides help to others." The scoring is done on a Likert scale ranging from 1 to 4. The skills are measured by determining the presence or absence of problem behaviors, resistance, and inappropriate responses as well as the extent to which prompts, assistance, and adaptations are needed. The assessment provides various forms of data collection, including daily/weekly data, manding data sheet, skill tracking, probing data sheet, and task analyses.

Reliability and Validity. Although some studies have used the EFL curriculum in their research to assess communication modalities (Orozco et al., 2022), no studies have been found on reliability and validity ("weak" levels of evidence). Future research should be conducted to determine the reliability and validity of EFL.

Considerations for Behavior Analysts. EFL can be used across the life span to develop IEP, transition, and vocational goals. EFL includes multiple forms to collect different types of data, which can be useful for behavior analysts to monitor behaviors on an ongoing basis. Also, this is one of the few assessments that includes a challenging behaviors domain. EFL is infrequently mentioned in surveys and reviews from the literature but appears to be increasing in popularity among behavior analysts. The categories in EFL are subjective. For example, it is difficult to distinguish between skills that are "good to have" and "nice to have." Behavior analysts should be cautious about using EFL because it lacks research on reliability and validity.

Discussion

The purpose of this article is to identify and describe several tools behavior analysts may use to assess skills in individuals with disabilities across a life span. We identified and reviewed eight skill-based assessments behavior analysts report commonly using in their practice. Most of the tools are appropriate to use for assessing skill strengths/deficits and program planning. Additionally, PEAK and ABLA are used for imitation and discrimination training. There is a wide variation across skill assessments in terms of age range, target skills, training needed, and psychometric properties. Administration times vary across assessments from anywhere from 20 minutes to 10 hours. Assessment time across tools is primarily determined by the format, with direct observation or testing formats taking the longest amount of time. Furthermore, we found assessments most commonly used by behavior analysts (e.g., VB-MAPP and ABLLS-R) have limited research in terms of reliability, validity, and effectiveness. To effectively measure and track behavior change, behavior analysts may want select assessments that are grounded in research, feasible to implement, sensitive to small changes, and match the needs of the target participants and setting.

There are few assessments that cover all age groups and areas of functioning-social-communication, daily living, and vocational and recreational skills. Behavior analysts may need to use multiple assessments to document behavior deficits across a range of behaviors. For example, ABLLS only assesses classroom readiness skills and does not address socialization, peer interaction, or self-help skills. Behavior analysts may want to pair these assessments with social skills curricula (e.g., SSIS-R) and/or a comprehensive assessment of daily living skills such as VABS. Likewise, very few assessments (e.g., VABS, AFLS, EFL) are used for individuals across their lifespan. Most assessments are geared for early childhood and school-age children for special education programming rather than post-secondary skills.

Even the assessments that are commonly used in behavior analytic literature (e.g., ABLLS-R, VB-MAPP) have limited research to document their reliability and validity. In contrast, tools with extensive research on reliability and validity are not commonly used in practice (e.g., PEAK). Ackley et al. (2019) found among available published ABA

assessment packages, less than 50% of the packages reported psychometric properties or evidence of efficacy. According to BACB (2017), lack of data on reliability, validity, efficacy, and efficiency of ABA assessments may limit a behavior analyst's ability to assess behavior and provide effective treatment for clients.

In addition to limited research on reliability and validity of ABA assessments, little research has been conducted on the effectiveness of commonly implemented skills assessments and curricula. Even though the curricula in this research embed research-based ABA strategies, the effectiveness of each protocol must also be evaluated to demonstrate that they adequately increase target skills (Ackley et al., 2019). For example, ABLA only assesses precursor skills such as imitation and discrimination. This assessment does not provide a clear path for intervention and skills building in daily living and vocational domains. In addition to overall effectiveness, there is a similar lack of studies on relative effectiveness comparing one ABA assessment to another. Little research exists to compare assessments, such as study comparing PEAK with VB-MAPP (Dixon et al., 2015).

Social validity is another important component for skill-based assessments in ABA. However, the existing survey and literature reviews do not include or address social validity of assessments. It is important to consider social validity when selecting assessments to ensure that the assessment is easy to conduct by various professionals, identifies and tracks relevant target behaviors for intervention, and results in acceptable consumer satisfaction.

There are other contingencies affecting behavior analysts' choice when selecting assessments. First, costly assessments may be prohibitive for behavior analysts, particularly those who practice independently or smaller rural school districts. Second, behavior analysts are more likely to use a readily available assessments in their workplace than those that are researchbased, which may limit their efficacy for program development and performance tracking. Third, behavior analysts may be limited to choosing assessments covered through insurance companies for billable hours. For example, insurance companies may prioritize the use of brief or shorter assessments to minimize costs. Finally, the governing bodies and professional organizations in the field such as the BACB, the Association for Behavior Analysis International (ABAI), and the Association for Professional Behavior Analysts (APBA) currently have no position statements or guidelines on evidence-based assessments. Such recommendations might ensure that behavior analysts select assessments that have been shown to be effective, valid, and reliable.

Limitations

Behavior analysts should consider some limitations of this article when choosing skillbased assessments in their practice. First, this is not a systematic review of ABA assessments but rather a description of skill-based assessments commonly used in the field as reported in surveys and systematic reviews. Second, we did not include assessments that were infrequently used by behavior analysts in their practice or in research. Additionally, we did not attempt to assess or survey which tools behavior analysts commonly use. Instead, we relied upon use surveys or previous review of assessments used in ABA field (Ackley et al., 2019; Padilla, 2020). Future researchers should not only focus on identifying effective interventions but also on identifying reliable, valid, and effective skill-based assessments.

Conclusions

When choosing ABA skill-based assessments, behavior analysts should follow recommended guidelines by BACB Professional and Ethical Compliance Code (2017). Before selecting an assessment, behavior analysts should review its reliability, validity, efficacy, and efficiency (BACB, 2017). Additionally, they should select assessments that are feasible to implement and are sensitive to small changes in client's behavior in order to continuously monitor progress and evaluate the treatment plan.

References

Achenbach, T. M. (1999). The Child Behavior Checklist and related instruments. In M. E. Maruish (Ed.), The use of psychological testing for treatment planning and outcomes assessment (2nd ed., pp. 429-466). Lawrence Erlbaum Associates Publishers.

Ackley, M., Subramanian, J. W., Moore, J. W., Litten, S., Lundy, M. P., & Bishop, S. K. (2019). A review of language development protocols for individuals with autism. Journal of Behavioral Education, 28(3), 362-388. https://doi.org/10. 1007/510864-019-09327-8

Aman, M. G., Singh, N. N., Stewart, A. W., & Field, C. (1985). The Aberrant Behavior Checklist: А behavior rating scale for the assessment of treatment effects. American Journal of Mental Deficiency, 89(5), 485-491. https://doi.org/10.1037/ t10453-000

Arick, J., Loos, L., Falco, R., & Krug, D. (2004). The STAR program (Strategies for teaching based on autism research). PRO-ED.

Behavior Analyst Certification Board [BACB]. (2017). BCBA/BCaBA task list (5th ed.). https:// www.bacb.com/wp-content/uploads/2020/05/ 170113-BCBA-BCaBA-task-list-5th-ed-.pdf.

Behavior Analyst Certification Board [BACB]. (2022). Ethics code for behavior analysts. https:// www.bacb.com/wp-content/uploads/2022/01/ Ethics-Code-for-Behavior-Analysts-230119-a.pdf

Barnes, С. S., Mellor, J. R., & Rehfeldt, К. A. (2014). Implementing the Verbal Behavior Milestones Assessment and Placement Program (VB-MAPP): Teaching assessment techniques. The Analysis of Verbal Behavior, 30(1), 36-47. https://doi.org/10. 1007/s40616-013-0004-5

Bayley, N. (2006). Bayley Scales of Infant and Toddler Development. Pearson.

Bolte, E. E., & Diehl, J. J. (2013). Measurement tools and target symptoms/skills used to assess treatment response for individuals with autism spectrum disorder. Journal of Autism and Developmental Disorders, 43(11), 2491-2501. https://doi. org/10.1007/s10803-013-1798-7

Channell, M. M., Mattie, L. J., Schworer, E. K., Fidler, D. J., & Esbensen, A. J. (2023). Using the Social Skills Improvement System (SSIS) Rating Scales to assess social skills in youth with Down syndrome. Frontiers in Psychology, 14, 1-13. https://doi.org/10.3389/fpsyg.2023.1105520

Cooper, J. O., Heron, T. E., & Heward, W. L. (2020). Applied behavior analysis. Pearson.

Conyers, C., Doole, A., Vause, T., Harapiak, S., Yu, D. С. T., & Martin, С. L. (2002). Predicting the relative efficacy of three presentation methods for assessing preferences on persons with developmental disabilities. Journal of Applied Behavior Analysis, 35(1), 49-58. https://doi.org/10.1901/ jaba.2002.35-49

Crocker, L., & Algina, J. (2008). Introduction to classical and modern test theory. Cengage Learning.

Crowe, L. M., Beauchamp, М. H., Catroppa, C., & Anderson, V. (2011). Social function assessment tools for children and adolescents: A systematic review from 1988 to 2010. Clinical Psychology Review, 31(5), 767-785. https://doi.org/10.1016/j.cpr.2011.03.008

Cusumano, D. L. (2007). Is it working?: An overview of curriculum based measurement and its uses for assessing instructional, intervention, or program effectiveness. The Behavior Analyst Today, 8(1), 24-34. https://doi.org/10.1037/h0100099

Daar, J. H., Negrelli, S., & Dixon, M. R. (2015). Derived emergence of WH question-answers in children with autism. Research in Autism Spectrum Disorders, 19, 59-71. https://doi.org/10.1016/j. rasd.2015.06.004

de Bildt, A., Kraijer, D., Sytema, S., & Minderaa, К. (2005). The psychometric properties of the Vineland Adaptive Behavior Scales in children and adolescents with mental retardation. Journal of Autism and Developmental Disorders, 35(1), 53-62. https://doi.org/10.1007/s10803-004-1033-7

Dixon, M. R. (2014). The PEAK Relational Training System: Direct Training Module. Shawnee Scientific Press.

Dixon, M. R., Belisle, J., Stanley, C., Rowsey, K., Daar, J. H., & Szekely, S. (2015). Toward a behavior analysis of complex language for children with autism: Evaluating the relationship between PEAK and the VB-MAPP. Journal of Developmental and Physical Disabilities, 27(2), 223-233. https:// doi.org/10.1007/s10882-014-9410-4

Dixon, M. R., Carman, J., Tyler, P. A., Whiting, $. W., Enoch, M. R., & Daar, J. H. (2014). PEAK relational training system for children with autism and developmental disabilities: Correlations with Peabody Picture Vocabulary Test and assessment reliability. Journal of Developmental and Physical Disabilities, 26(5), 603-614. https://doi.org/ 10.1007/s10882-014-9384-2

Dixon, M. R., Stanley, С. R., Belisle, J., 8: Rowsey, К. Е. (2016). The test-retest and interrater reliability of the Promoting the Emergence of Advanced Knowledge-Direct Training assessment for use with individuals with autism and related disabilities. Behavior Analysis: Research and Practice, 16(1), 34-40. https://doi.org/10.1037/bar0000027

Dixon, М. R., Whiting, S. W., Rowsey, K., & Belisly, J. (2014). Assessing the relationship between intelligence and the PEAK Relational Training System. Research in Autism Spectrum Disorders, 8(9), 1208- 1213. https://doi.org/10.1016/j.rasd.2014.05.005

Doehring, P., Gigliotti, D., Calkins, H., & Cain, D. (2008, February). The utility of the ABLLS in comprehensive assessment and educational planning: A comparison of instruments (Conference Presentation). Association for Behavior Analysis-Autism Conference, Atlanta, GA, United States. http://www.asdroadmap.org/ assets/aba-2008-ablls-poster-2-handout.pdf

Duker, P. (1999). The Verbal Behavior Assessment Scale (VerBAS): Construct validity, reliability, and internal consistency. Research in Developmental

Disabilities, 20(5), 347-353. https://doi.org/ 10.1016/S0891-4222(99)00016-5

Durand, V. M., & Crimmins, D. B. (1988). Identifying the variables maintaining selfinjurious behavior. Journal of Autism and Developmental Disorders, 18(1), 99-117. https://doi.org/10.1007/BF02211821

Freitas, L. C., & Del Prette, Z. A. (2015). Social Skills Rating System-Brazilian version: New exploratory and confirmatory factorial analyses. Avances en Psicología Latinoamericana, 33(1), 135-156. https:// doi.org/10.12804/ap133.01.2015.10

Gamst-Klaussen, T., Rasmussen, L. M. P., Svartdal, F., & Strgmgren, B. (2016). Comparability of the Social Skills Improvement System to the Social Skills Rating System: A Norwegian study. Scandinavian Journal of Educational Research, 60(1), 20-31. https://doi.org/10.1080/00313831.2014.971864

Gould, E., Dixon, D. R., Najdowski, A. C., Smith, M. N., & Tarbox, J. (2011). A review of assessments for determining the content of early intensive behavioral intervention programs for autism spectrum disorders. Research in Autism Spectrum Disorders, 5(3), 990-1002. https://doi.org/10. 1016/j.rasd.2011.01.012

Gresham, F. M., & Elliot, S. N. (1990). Social Skills Rating System. PsycTESTS Dataset.

Gresham, F. M., & Elliott, S. N. (2008). Social Skills Improvement System (SSIS) Rating Scales. Pearson. Gresham, Е. M., Elliott, S. N., Vance, М. J., & Cook, C. R. (2011). Comparability of the Social Skills Rating System to the Social Skills Improvement System: Content and psychometric comparisons across elementary and secondary age levels. School Psychology Quarterly, 26(1), 27-44. https://doi.

org/10.1037/a0022662

Hanratty, J., Livingstone, N., Robalino, S., Terwee, С. B., Glod, M., Oono, I. P., Rodgers, J., Macdonald, G., & McConachie, H. (2015). Systematic review of the measurement properties of tools used to measure behaviour problems in young children with autism. PLoS One, 10(12), 1-21. https://doi.org/10.1371/journal.pone.0144649

Horstmann, K. T., Knaut, M., & Ziegler, M. (2019). Criterion validity. In V. Zeigler-Hill & T. Shackelford. (Eds.), Encyclopedia of personality and individual differences. Springer. https://doi.org/10.1007/978-3-31928099-8_1293-1

Hayes, S. C., Barnes-Holmes, D., & Roche, В. (2001). Relational frame theory: A post Skinnerian approach to language and cognition. Plenum Press.

Iwata, B., & DeLeon, 1. (2005). The Functional Analysis Screening Tool. The Florida Center on Self-Injury, University of Florida.

Kamphaus, R. W., & Reynolds, C. R. (2007). Behavior Assessment System for Children - second edition (BASC-2). Pearson. Kennedy, C. H. (1992). Trends in the measurement of social validity. The Behavior Analyst, 15 (2), 147- 156. https://doi.org/10.1007/BF03392597

Kerr, N., Meyerson, L., Flora, J., Tharinger, D., Schallert, D., Casey, L., & Fehr, M. J. (1977). The measurement of motor, visual and auditory discrimination skills in mentally retarded children and adults and in young normal children. Rehabilitation Psychology, 24(3), 91-206. https://doi. org/10.1037/h0090912

Lord, C., Rutter, M., DiLavore, P. C., & Risi, S. (1999). Autism Diagnostic Observation Schedule-WPS (ADOS-WPS). Western Psychological Services.

Malkin, A., Dixon, M. R., Speelman, К. C., & Luke, N. (2017). Evaluating the relationships between the PEAK Relational Training System-Direct Training Module, Assessment of Basic Language and Learning Skills-Revised, and the Vineland Adaptive Behavior Scales-II. Journal of Developmental and Physical Disabilities, 29(2), 341-351. https://doi.org/10.1007/s10882-016-9527-8

Martin, С. L., Thorsteinsson, J. R., Yu, С. T., Martin, T. L., & Vause, T. (2008). The Assessment of Basic Learning Abilities Test for predicting learning of persons with intellectual disabilities: À review. Behavior Modification, 32(2),228-247. https://doi. org/10.1177/0145445507309022

McGreevy, P., Fry, T., & Cornwall, С. (2012). Essential for Living. McGreevy.

McKeel, A., Rowsey, K., Dixon, M. R., & Daar, J. H. (2015). Correlation between PEAK Relational Training System and one-word picture vocabulary tests. Research in Autism Spectrum Disorders, 12, 34-39. https://doi.org/10.1016/j.rasd.2014.12.007

Moore, J. W., Rizer, H. B., Warren, L. K., Yeager, M. G., Brewer, R. R., Barker, L. K., Newborne, B., Russo, К. L., & Potter, М. (2020). An initial evaluation of an assessment method for the PEAK Relational System Direct Training Module. Behavior Analysis in Practice, 13(1), 126-136. https:// doi.org/10.1007/s40617-019-00387-w

Montallana, K. L., Gard, B. M., Lotfizadeh, A. D., & Poling, A. (2019). Inter-rater agreement for the milestones and barriers assessments of the Verbal Behavior Milestones Assessment and Placement Program (VB-MAPP). Journal of Autism and Developmental Disorders, 49(5), 2015-2023. https://doi. org/10.1007/s10803-019-03879-4

Moran, L., Stewart, I, McElwee, J., & Ming, 5. (2010). Brief report: The Training and Assessment of Relational Precursors and Abilities (TARPA): A preliminary analysis. Journal of Autism and Developmental Disorders, 40(9), 1149-1153. https://doi.org/10.1007/s10803-010-0968-0

New England Center for Children. (2013). Autism Curriculum Encyclopedia (ACE). Бир: / /www.acenecc. org/.

O'Neill, К. E., Albin, К. W., Storey, K., Horner, R. H., & Sprague, J. R. (2015). Functional assessment and program development. Cengage Learning.

Orozco, D., Cividini-Motta, C., Campos, C., & Brolmann, H. A. (2023). Teaching mands: Correspondence among acquisition, recommendations of the Essential for Living communication modality assessment, and preference. Behavior Analysis in Practice, 16(3), 812-825. https://doi.org/10. 1007/s40617-022-00764-y

Padilla, K. L. (2020). Global assessment use and practices in applied behavior analysis: Surveying the field. Research in Autism Spectrum Disorders, 79, 101676. https://doi.org/10.1016/j.rasd.2020.101676

Padilla, К. L., & Akers, J. 5. (2021). Content validity evidence for the Verbal Behavior Milestones Assessment and Placement Program. Journal of Autism and Developmental Disorders, 51(11), 4054- 4066. https://doi.org/10.1007/s10803-020-04864-y

Padilla, K. L., Weston, R., Morgan, G. B., Lively, P., & O'Guinn, N. (2023). Validity and reliability evidence for assessments based in applied behavior analysis: А systematic review. Behavior Modification, 47(1), 247-288. https://doi.org/10.1177/ 01454455221098151

Partington, J. W. (2010). The ABLLS-R - The Assessment of Basic Language and Learning Skills-Revised. Behavior Analysts, Inc.

Partington, J. W., Bailey, A., & Partington, S. W. (2018). A pilot study examining the test-retest and internal consistency reliability of the ABLLS-R. Journal of Psychoeducational Assessment, 36(4), 405-410. https://doi.org/10.1177/0734282916678348

Partington, J. W., & Mueller, M. M. (2015). The Assessment of Functional Living Skills (AFLS): Independent living skills assessment protocol, an assessment, skills tracking system, and curriculum guide for skills that are essential for independence. Behavior Analysts, Inc.

Pepperdine, C. R., & Mccrimmon, A. W. (2018). Test review: Vineland Adaptive Behavior Scales, Third Edition (Vineland-3) by Sparrow, 5. S., Cicchetti, D. V., & Saulnier, C. A. Canadian Journal of School Psychology, 22(2), 157-163. https://doi. org/10.1177/0829573517733845

Pritchard, J. K. (2013). ABLLS-R kit. Behavior Analysis in Practice, 6(2), 86-87. https://doi. org/10.1007/BF0339181

Reyer, H. S., & Sturmey, P. (2006). The Assessment of Basic Learning Abilities (ABLA) test predicts the relative efficacy of task preferences for persons with developmental disabilities. Journal of Intellectual Disability Research, 50(6), 404-409. https://doi.org/10.1111/j.1365-2788.2005.00780.x

Rezutek, P., Yu, C. T., & Thorne, L. (2021). Assessing discrimination skills of individuals with developmental and physical disabilities using microswitches. Journal on Developmental Disabilities, 26(1), 1-19.

Rogers, S. J., & Dawson, С. (2010). Early Start Denver Model for young children with autism: Promoting language, learning, and engagement. The Guilford Press.

Rogers, S. J., & Vismara, L. A. (2008). Evidencebased comprehensive treatments for early autism. Journal of Clinical Child and Adolescent Psychology, 37(1), 8-38. https://doi.org/10.1080/ 15374410701817808

Roid, G. H., & Pomplun, M. (2012). The StanfordBinet Intelligence Scales. The Guilford Press.

Rowsey, К. E., Belisle, J., & Dixon, М. R. (2015). Principal component analysis of the PEAK Relational Training System. Journal of Developmental and Physical Disabilities, 27(1), 15-23. https:// doi.org/10.1007/s10882-014-9398-9

Semel, E., Wiig, E. H., & Secord, W. A. (2003). Clinical Evaluation of Language Fundamentals, fourth edition (CELF-4). The Psychological Corporation.

Skills Global. (2017). Research on SKILLS® and ABA. https://www.skillsforautism.com/Research.

Sparrow, S. S., Cicchetti, D. V., & Saulnier, C. A. (2016). Vineland Adaptive Behavior Scales, third edition (Vineland-3). NCS Pearson.

Stewart, I., McElwee, J., & Ming, S. (2010). A critical analysis of conventional descriptions of levels employed in the Assessment of Basic Learning Abilities. The Behavior Analyst, 33(1), 127-131. https://doi.org/10.1007/BF03392208

Stubbings, V., & Martin, G. (1995). The Assessment of Basic Learning Abilities Test for predicting performance of developmentally disabled persons on prevocational training tasks. International Journal of Practical Approaches to Disability, 19(1), 12-17.

Sundberg, M. L. (2008). VB-MAPP: Verbal Behavior Milestones Assessment and Placement Program. AVB Press.

Sundberg, M. L. (2014). VB-MAPP: Verbal Behavior Milestones Assessment and Placement Program: A language and social skills assessment program for children with autism or other developmental disabilities. AVB Press.

Usry, J., Partington, S. W., & Partington, J. W. (2018). Using expert panels to examine the content validity and interrater reliability of the ABLLS-R. Journal of Developmental and Physical Disabilities, 30(1), 27-38. https://doi.org/10.1007/ s10882-017-9574-9

Van der Oord, S., Van der Meulen, E. M., Prins, Р. J., Oosterlaan, J., Buitelaar, J. K., & Emmelkamp, P. M. (2005). A psychometric evaluation of the Social Skills Rating System in children with attention deficit hyperactivity disorder. Behaviour Research and Therapy, 43(6), 733-746. https:// doi.org/10.1016/j.brat.2004.06.004

Wacker, D. P., Steil, D. A., & Greenebaum, Е. T. (1983). Assessment of discrimination skills of multiply handicapped preschoolers and prediction of classroom task performance. Journal of the Association for the Severely Handicapped, 8(2), 65-78. https://doi.org/10.1177/154079698300800207

Wechsler, D. (2014). Wechsler Intelligence Scale for Children-fifth edition: Technical and interpretive manual. Pearson.

Wheeler, K., Favela, A., Hamrick, J., Dillard, M. K., Marzban, F., & Banda, D. (2023). A pilot program for teaching sexuality and relationships to adults with autism and developmental disabilities. Journal of Intellectual Disabilities. https://doi.org/ 10.1177/17446295231225520

Woodcock, R. W., Mather, N., McGrew, K. S., & Wendling, В. J. (2001). Woodcock-Johnson III Tests of Cognitive Abilities. Western Psychological Services.

Zimmerman, 1. L., Steiner, У. С, & Pond, К. Е. (2002). Preschool Language Scale, Fourth Edition. The Psychological Corporation.