The institutional landscape of cognitive impairment and developmental support has undergone profound paradigm shifts over the past century and a half, transitioning from custodial segregation toward rights-based ecological empowerment. At the forefront of this conceptual evolution stands the American Association on Intellectual and Developmental Disabilities (AAIDD), the world’s oldest and most influential multidisciplinary organization devoted to the study, classification, and support of individuals with intellectual and developmental conditions. Through its authoritative diagnostic manuals, validated psychometric instruments, and advocacy-driven scholarship, the AAIDD has systematically dismantled deficit-based models in favor of a multidimensional framework centered on human dignity, individualized supports, and community participation.
American Association on Intellectual and Developmental Disabilities (AAIDD)
1. Concise Definition
The American Association on Intellectual and Developmental Disabilities (AAIDD) is an international, interdisciplinary professional association of researchers, clinicians, educators, policymakers, and advocates dedicated to advancing the rights, well-being, and community inclusion of individuals with intellectual and developmental disabilities. Functioning as both a scientific society and a standard-setting body, the association produces definitive diagnostic and classification systems, sponsors peer-reviewed scholarly journals, and establishes evidence-based practices that govern clinical, educational, and legal frameworks globally.
Conceptually, the AAIDD defines intellectual disability as a condition characterized by significant limitations both in intellectual functioning (reasoning, learning, and problem solving) and in adaptive behavior, which encompasses a broad range of everyday social and practical skills. Crucially, under the association’s contemporary diagnostic criteria, this condition originates during the developmental period—specifically before the age of 22—and is understood not as an immutable personal defect, but as an ecological manifestation of the operational fit between personal capacities and environmental demands.
Beyond diagnostic definition, the AAIDD is renowned for articulating the “Supports Paradigm.” This transformative theoretical orientation posits that the primary purpose of assessing an individual’s limitations is to systematically determine, organize, and deliver personalized accommodations, modifications, and community resources. Under this model, appropriately matched and sustained supports significantly enhance personal autonomy, civic engagement, and overall quality of life.
2. Etymology & Linguistic Origin
The etymological trajectory of the AAIDD documents the broader socio-cultural and scientific transformation of disability terminology over nearly 150 years. The organization was founded in 1876 under the title Association of Medical Officers of American Institutions for Idiotic and Feeble-Minded Persons. At that time, terms such as “idiot” (derived from the Greek idiōtēs, meaning a private person or layman lacking professional knowledge) and “feeble-minded” functioned as objective medical and taxonomic categories denoting degrees of congenital or early-acquired mental deficiency.
As scientific paradigms shifted and colloquial usage imbued early nomenclature with pejorative connotations, the organization iteratively renamed itself to reflect emerging values and scientific accuracy. In 1906, it became the American Association for the Study of the Feeble-Minded. By 1933, adopting a clinical framework centered on functional impairment, the body renamed itself the American Association on Mental Deficiency (AAMD). In 1987, reflecting a preferred international nomenclature, it changed its moniker to the American Association on Mental Retardation (AAMR), utilizing the Latin root retardare (meaning to delay, slow down, or impede).
In 2006, following extensive deliberation among self-advocates, clinicians, and researchers, the membership voted overwhelmingly to adopt its current title: the American Association on Intellectual and Developmental Disabilities (AAIDD), officially taking effect on January 1, 2007. This final linguistic shift abandoned the stigmatizing descriptor “mental retardation” entirely. It embraced the internationally accepted umbrella terminology “intellectual disability,” which emphasizes cognitive processing and functional competence, coupled with “developmental disability,” which highlights the lifespan origins and structural supports required across comprehensive biological, neurological, and social contexts.
3. Pronunciation & Grammatical Form
The term is pronounced phonetically as an acronym using the individual letters: /eɪ-eɪ-aɪ-diː-diː/ (AY-AY-EYE-DEE-DEE), or pronounced in full as the American Association on Intellectual and Developmental Disabilities (əˈmɛrɪkən əˌsousiˈeɪʃən ɒn ˌɪntəˈlɛktʃuəl ənd dɪˌvɛləpˈmɛntəl ˌdɪsəˈbɪlətiz).
Grammatically, “AAIDD” functions as a proper noun phrase. It regularly operates as an attributive noun or modifier in professional literature, appearing in phrases such as the “AAIDD diagnostic system,” “AAIDD classification manual,” or “AAIDD multidimensional model.” In scholarly and legal writing, the definite article “the” typically precedes the acronym (e.g., “as mandated by the AAIDD guidelines”).
4. Detailed Conceptual Explanation
The conceptual framework pioneered by the AAIDD departs fundamentally from traditional pathological or psycho-medical models that locate disability solely within the biological or psychological makeup of the individual. Instead, the association conceptualizes disability as an ecological phenomenon. In this understanding, human functioning is viewed as the dynamic, ongoing outcome of reciprocal interactions between personal capacities (intellectual, physical, psychological) and environmental contexts (physical, social, cultural, and political environments).
To capture this complex ecology, the AAIDD organizes human functioning across five distinct dimensions:
- Dimension I: Intellectual Abilities: Encompassing general mental capacity, including reasoning, planning, abstract thinking, complex idea comprehension, rapid learning, and experiential learning.
- Dimension II: Adaptive Behavior: The collection of conceptual, social, and practical skills learned and performed by individuals in their everyday lives.
- Dimension III: Health: A holistic appraisal of physical health, mental health, and underlying etiological or genetic factors affecting overall vitality and organic resilience.
- Dimension IV: Participation: The scope and quality of an individual’s involvement in typical home, work, educational, recreation, and civic life roles within inclusive society.
- Dimension V: Context: The overarching micro-, meso-, and macrosystems comprising personal environments, immediate community structures, societal institutions, laws, cultural attitudes, and socioeconomic factors.
Interposed between these five dimensions and overall human functioning sits the defining innovation of the AAIDD model: Supports. Supports are formal and informal resources and strategies aimed at promoting an individual’s personal development, education, independence, and overall well-being. Under this formulation, when environmental barriers are removed and personalized supports are accurately aligned with an individual’s profile of needs, the functional manifestation of the disability is lessened, and participatory equity is maximized.
Consequently, the boundaries of the construct are functional rather than strictly biological. Intellectual disability cannot be diagnosed solely on the basis of a low psychometric Intelligence Quotient (IQ). Rather, it requires evidence of concurrent limitations in everyday adaptive behavior, validated within community environments typical of the individual’s age peers and cultural background, emerging within the formative developmental epoch.
5. Historical Development
The inception of the AAIDD took place on June 6, 1876, at the Pennsylvania Training School for Feeble-Minded Children in Elwyn, Pennsylvania. A pioneering cohort of six residential institution superintendents, spearheaded by Dr. Édouard Séguin—a student of Jean-Marc Gaspard Itard and an ardent champion of sensory-physiological education—convened to establish the Association of Medical Officers of American Institutions for Idiotic and Feeble-Minded Persons. Séguin served as its first president, establishing a tradition of combining medical inquiry with pedagogical rehabilitation.
Throughout the early twentieth century, the organization became intricately entangled with the rise of the mental testing movement led by figures like Henry H. Goddard, who introduced the Binet-Simon intelligence scale to North America. While this period witnessed the problematic proliferation of eugenic theories and prolonged institutionalization across the United States, internal scholarship within the association progressively laid the groundwork for modern empirical diagnostics. In 1921, the association published its first formal diagnostic manual, inaugurating a series of reference texts that would establish diagnostic criteria across clinical domains worldwide.
A critical historical juncture occurred in 1959 with the publication of the 5th Edition of the classification manual, authored under the leadership of Rick Heber. This edition officially integrated the construct of adaptive behavior alongside measured intelligence, establishing that subaverage general intellectual functioning must coexist with impairments in adaptive behavior to warrant diagnosis. This dual-criterion model fundamentally disrupted purely psychometric approaches.
During the latter half of the twentieth century, catalyzed by the civil rights movement, parent-led grassroots activism, and the normalization principle advanced by Wolf Wolfensberger and Bengt Nirje, the organization shifted decisively toward deinstitutionalization and community integration. The landmark 9th (1992) and 10th (2002) editions of the classification manual, steered by Ruth Luckasson and colleagues, abandoned traditional severity sub-tiers (mild, moderate, severe, profound) based strictly on IQ ranges. Instead, they introduced an unprecedented framework defining individuals by the intensity of supports they require (intermittent, limited, extensive, or pervasive).
In the legal sphere, the AAIDD’s scientific standards have shaped constitutional jurisprudence. In the landmark United States Supreme Court ruling Atkins v. Virginia (2002), which held that the execution of individuals with intellectual disabilities violates the Eighth Amendment’s ban on cruel and unusual punishment, the Court cited the AAIDD’s clinical definition as an authoritative benchmark. In 2021, the AAIDD published the 12th Edition of its manual (Intellectual Disability: Definition, Diagnosis, Classification, and Systems of Supports), which updated the age-of-onset threshold from age 18 to age 22, aligning the definition with contemporary neurodevelopmental science demonstrating extended prefrontal cortex maturation into early adulthood.
6. Theoretical Foundations
The theoretical infrastructure of the AAIDD integrates insights from ecological systems theory, developmental psychology, cognitive neuroscience, and the social model of disability. Principal among these is Urie Bronfenbrenner’s ecological systems theory, which posits that human development cannot be isolated from the multi-layered social architecture surrounding an individual. The AAIDD operationalizes this principle by insisting that adaptive limitations must be judged relative to cultural norms, language communities, and environmental opportunities rather than treated as decontextualized individual deficits.
Complementing this ecological orientation is the human rights and citizenship paradigm, formally codified in the United Nations Convention on the Rights of Persons with Disabilities (UN CRPD). The AAIDD model rejects paternalistic approaches to caregiving, operating instead on principles of self-determination, legal agency, and non-discrimination. Self-determination theory—advocated heavily within the association by scholars such as Michael Wehmeyer—posits that individuals who act as primary causal agents in their own lives achieve higher levels of emotional well-being, community participation, and long-term personal success.
The theoretical paradigm of the AAIDD also draws heavily from positive psychology. Rather than cataloging psychopathological symptoms or functional deficits in a deficit-focused ledger, the association’s conceptual frameworks evaluate individual strengths, personal competencies, aspirational goals, and environmental possibilities. Disability is thus conceptualized as a universal aspect of the human condition characterized by a functional discrepancy between personal competencies and contextual expectations, bridgeable through individualized supports.
7. Key Components, Types & Dimensions
The AAIDD framework comprises precise components, classification matrices, and operational dimensions designed for clinical, educational, and systemic implementation:
- The Three Core Diagnostic Criteria:
1. Significant intellectual deficits: Performance approximately two standard deviations below the population mean on an individualized, standardized, psychometrically valid general intelligence measure (incorporating standard error of measurement, typically an IQ of 70 to 75).
2. Significant adaptive behavior deficits: Performance at least two standard deviations below the mean on an individualized, standardized measure across at least one of three domains: conceptual, social, or practical, or on an overall composite score.
3. Developmental onset: Documentation that intellectual and adaptive impairments were manifest during the developmental period, operationally defined as prior to the individual turning 22 years of age. - The Three Domains of Adaptive Behavior:
1. Conceptual Skills: Receptive and expressive language, reading, writing, mathematical concepts, money management, self-direction, and cognitive orientation.
2. Social Skills: Interpersonal communication, empathy, gullibility and credulity (critical in forensic domains), social judgment, following social rules, avoiding victimization, and establishing friendships.
3. Practical Skills: Personal activities of daily living (bathing, dressing, eating), instrumental activities of daily living (meal preparation, housekeeping, public transit navigation, scheduling), occupational competencies, and maintaining personal health and safety. - The Four Levels of Support Intensity:
1. Intermittent: Supports provided on an “as-needed” basis, characterized by episodic, acute, or transitional requirements (e.g., job loss, familial crisis, or sudden medical transition).
2. Limited: Consistent, time-limited supports characterized by fixed scheduling and specific goals (e.g., transitional vocational training or short-term independent living skills instruction).
3. Extensive: Regular, ongoing, long-term supports characterized by daily involvement in specific life settings (e.g., sustained support within supportive employment or permanent home care assistance).
4. Pervasive: Constant, high-intensity, life-sustaining supports distributed across virtually all living environments, potentially involving invasive physical accommodations or round-the-clock monitoring. - Operational Structural Subsystems:
The AAIDD functions through a governance structure consisting of an elected Board of Directors, a series of specialized professional interest divisions (e.g., Psychology, Legal Process and Advocacy, Direct Support Professionals, Health and Wellness), localized state and regional chapters, and peer-reviewed publishing arms.
8. Examples & Illustrative Cases
The application of the AAIDD framework transforms clinical reasoning and service delivery, as demonstrated in the following real-world clinical contexts:
Case Illustration 1: The Transition-Age Student (Educational Context)
Marcus is a 20-year-old male with a history of generalized cognitive delays. Standardized intelligence testing reveals a Full-Scale IQ of 68 (95% confidence interval: 64–72). While his score establishes significant intellectual deficits, classical medical models might prematurely assign Marcus a static diagnosis without evaluating contextual functioning. Under the AAIDD model, a comprehensive adaptive assessment is administered using the Diagnostic Adaptive Behavior Scale (DABS). Marcus displays standard scores within typical limits for social and practical navigation within his neighborhood; however, his conceptual score is 3.1 standard deviations below the mean, with severe deficits in financial numeracy, understanding lease agreements, and independent reading. By pinpointing this specific conceptual impairment before age 22, the AAIDD diagnostic threshold is met. Rather than placing Marcus into an undifferentiated day-habilitation program, his educational team deploys an Individualized Support Plan (ISP) delivering extensive supports for banking, financial literacy, and digital scheduling, alongside intermittent supports for public transit navigation, facilitating his employment at a local distribution center.
Case Illustration 2: Capital Jurisprudence (Forensic Context)
In a legal proceeding assessing intellectual disability under the Eighth Amendment, a 45-year-old defendant faces capital murder charges. Archival school records from childhood demonstrate severe academic struggles, but formal psychometric evaluation was never administered prior to his incarceration. Historical adaptive functioning is reconstructed retrospectively using standardized interviews with surviving teachers, siblings, and community members, alongside correctional records. Forensic psychologists applying AAIDD standards demonstrate that the defendant exhibited profound limitations in social judgment, gullibility, and self-direction prior to his twentieth birthday, and historical documentation shows an inability to manage daily personal finances or comprehend instructions without peer intervention. By applying the AAIDD’s expanded age-of-onset criterion (age 22) and establishing concurrent intellectual and adaptive impairments with psychometric rigor, the defense establishes the clinical presence of an intellectual disability, legally precluding the state from seeking capital punishment.
9. Measurement & Assessment
Assessment within the AAIDD tradition rejects single-score decision-making and requires multidimensional, culturally competent psychometrics. The association emphasizes that intellectual assessment must be conducted using modern, norm-referenced intelligence batteries (e.g., Wechsler Adult Intelligence Scale, Stanford-Binet Intelligence Scales) administered by qualified psychological examiners. The AAIDD highlights critical statistical caveats often overlooked in generic assessments, including the standard error of measurement (SEM), confidence intervals, and the “Flynn effect”—the empirical observation that standardized IQ test norms drift over time, necessitating psychometric corrections when outdated test versions are utilized.
To standardize the assessment of adaptive behavior, the AAIDD developed and published the Diagnostic Adaptive Behavior Scale (DABS). Unlike traditional rating scales that measure broad functioning, the DABS is specifically normed and constructed to identify significant limitations at the diagnostic cutoff point (approximately two standard deviations below the population mean) across conceptual, social, and practical domains. It pays particular attention to subtle, hard-to-measure skills such as gullibility, gullibility resistance, credulity, vulnerability to manipulation, and financial literacy.
To operationalize its theoretical emphasis on individual supports, the AAIDD created the Supports Intensity Scale (SIS), available in validated versions for adults (SIS-A) and children (SIS-C). Unlike conventional assessments that measure what an individual cannot do, the SIS measures the frequency, daily duration, and type of support an individual requires to successfully participate in regular community activities across home living, community living, lifelong learning, employment, health and safety, social interactions, and advocacy. The SIS transforms diagnostic data directly into practical service budgets and individualized support blueprints.
10. Applications & Practical Significance
The applications of the AAIDD’s frameworks are felt across clinical practice, public policy, the legal system, and community service models:
- Clinical and Diagnostic Practice: The AAIDD criteria serve as the gold standard for clinical psychologists, developmental pediatricians, and neuropsychologists. The World Health Organization’s International Classification of Diseases (ICD-11) and the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR) have substantially harmonized their core criteria for intellectual developmental disorder with the AAIDD’s structural definitions.
- Forensic and Jurisprudential Arenas: In capital punishment determinations, civil competency hearings, and Social Security disability adjudications, AAIDD guidelines are routinely recognized by state and federal courts as the primary authoritative source for establishing functional limitation thresholds, particularly regarding the evaluation of adaptive deficits and the management of borderline intellectual scores.
- Resource Allocation and Policy: State developmental disability agencies use AAIDD instruments—especially the SIS—to objectively determine funding bands and Medicaid Home and Community-Based Services (HCBS) waiver allocations. By tying funding directly to measured support needs rather than static diagnostic labels, states can disburse public resources more equitably.
- Person-Centered Planning: The AAIDD supports model serves as the operational foundation for person-centered organizational practices. Direct support professionals, case managers, and vocational coaches use the framework to design customized lifestyle arrangements that promote maximum community integration and autonomous decision-making.
11. Research & Empirical Evidence
Empirical scholarship generated under the auspices of the AAIDD has profoundly reshaped the literature on cognitive disability. The organization publishes two leading international, peer-reviewed journals: the American Journal on Intellectual and Developmental Disabilities (AJIDD), which focuses primarily on fundamental biological, behavioral, and psychological research, and Intellectual and Developmental Disabilities (IDD), which prioritizes policy, service delivery models, and translational research.
Decades of empirical studies led by researchers such as Robert L. Schalock, James R. Thompson, Karrie A. Shogren, Marc J. Tassé, and Ruth Luckasson have validated the Supports Model. Research has repeatedly demonstrated that when organizations align support provision directly with standardized needs profiles identified via the SIS, individuals experience statistically significant gains in subjective quality of life, personal independence, community participation, and psychological well-being. Furthermore, structural equation modeling across large cross-national samples has validated the tripartite model of adaptive behavior (conceptual, social, practical), confirming that these constructs are psychometrically distinct yet interconnected facets of human adaptation.
Empirical inquiries have also addressed the stability of adaptive behavior across the lifespan. Studies show that while measured cognitive ability (IQ) remains relatively stable in adulthood, adaptive behavior scores can increase significantly when an individual is placed in supportive, highly enriched community environments. This finding provides empirical proof that functional disability is mutable and mediated by external accommodations.
12. Cultural & Cross-Cultural Considerations
Adaptive behavior is inherently culturally bound. What constitutes normative, expected functional independence in an urban, technologically complex, individualistic society may differ markedly from expectations within rural, agrarian, or collectivist cultural environments. The AAIDD explicitly mandates that adaptive behavior must be interpreted within the context of the individual’s community environment, cultural heritage, and linguistic background.
Standardized diagnostic tools often fail when applied across different cultural environments if they assume specific experiences with technology, formal schooling, or localized financial practices. Consequently, the AAIDD requires that examiners evaluate whether an apparent adaptive deficit reflects a true functional impairment or simply limited opportunity, acculturation variations, or linguistic mismatch. In response to global demands, the AAIDD has partnered with universities and governmental bodies worldwide to translate, adapt, and renorm the Supports Intensity Scale and DABS across more than 20 languages and distinct regional jurisdictions, including Spain, Italy, Taiwan, Belgium, and Chile, ensuring that assessment parameters respect cross-cultural diversity.
13. Criticisms, Debates & Limitations
Despite its widespread authority, the AAIDD’s paradigms continue to generate clinical, legal, and operational debates. A longstanding tension involves the Flynn effect and psychometric cut-off points. In legal contexts—particularly capital litigation—opposing counsel frequently debate whether an IQ score of 71 versus 69 constitutes a definitive boundary of intellectual impairment. Although the AAIDD unequivocally states that IQ cutoffs are ranges that must account for standard errors of measurement and adaptive performance, the legal system’s demand for bright-line boundaries creates friction with clinical nuance, as observed in cases like Hall v. Florida (2014) and Moore v. Texas (2017).
Another critique centers on the resource allocation formulas driven by the Supports Intensity Scale. Some disability advocates and families caution that state agencies occasionally use SIS scoring matrices to mechanically cap or reduce Medicaid support allocations, converting an instrument designed for personal empowerment into a bureaucratic mechanism for cost containment.
Furthermore, the modern neurodiversity movement has challenged lingering elements of the developmental disability framework. While acknowledging that the AAIDD moved far beyond historical deficit-pathology models, neurodiversity theorists argue that any system fundamentally based on calculating standard deviations from a statistical “norm” still relies on a deficits-based logic that frames neurological divergence as a pathology requiring remediation, rather than a natural expression of human biodiversity.
14. Related Terms & Distinctions
Clarifying terminology is essential to avoid conceptual conflation among clinicians, educators, and researchers:
- Intellectual Disability (ID) vs. Developmental Disability (DD):
Intellectual Disability refers specifically to significant limitations in both intellectual functioning and adaptive behavior originating during the developmental epoch. Developmental Disability is a broader umbrella category governed in the U.S. by federal law (the Developmental Disabilities Assistance and Bill of Rights Act), encompassing chronic, severe physical or mental impairments—such as cerebral palsy, severe autism, or spina bifida—that manifest before age 22 and result in substantial functional limitations in major life activities, regardless of whether intellectual functioning itself is impaired. - AAIDD vs. American Psychiatric Association (APA/DSM-5-TR):
While both systems harmonize around the triad of intellectual deficits, adaptive deficits, and developmental onset, the AAIDD manual is an ecological, supports-oriented classification framework designed primarily to guide long-term supports and community living. The APA’s DSM-5-TR is a diagnostic nosology formulated primarily for psychiatric and psychological differential diagnosis and clinical coding. - AAIDD vs. The Arc:
The AAIDD is a professional, scholarly, and standard-setting association comprising scientists, clinicians, academics, and administrators. The Arc of the United States is primarily a community-based grassroots advocacy and service organization comprised of individuals with disabilities, their families, and civil rights advocates. - Supports Model vs. Deficit-Medical Model:
The traditional medical model assesses functional limitations to assign a diagnostic label that classifies the person’s internal pathological deficits. The AAIDD supports model assesses limitations solely to map and provision the individualized environmental modifications and personalized supports needed to bridge the gap between capability and community participation.
15. Summary / Key Takeaways
The American Association on Intellectual and Developmental Disabilities (AAIDD) stands as the world’s preeminent scholarly authority on the definition, diagnostic conceptualization, and ecological support of intellectual disability. Founded in 1876, the association has steered the field through successive paradigms—from custodial institutionalization to medicalized deficit models, and finally to modern systems characterized by human rights, personal self-determination, and the Supports Paradigm.
By defining intellectual disability through an ecological interaction of intellectual capacity, adaptive behavior, health, participation, and context, the AAIDD ensures that individuals are evaluated by the environmental accommodations they need to thrive rather than by arbitrary, isolated deficits. Supported by psychometrically validated instruments such as the DABS and the SIS, the AAIDD’s standards govern modern clinical assessments, inform state resource systems, shape high-stakes judicial determinations, and safeguard the fundamental civil rights and dignity of individuals with developmental conditions across the globe.
Ultimately, the work of the AAIDD illustrates that disability is not an intrinsic flaw of the individual, but an inherent dimension of human variation that can be effectively accommodated through systemic, personalized, and compassionate community supports.
References
- American Psychiatric Association. (2022). Diagnostic and statistical manual of mental disorders (5th ed., text rev.). American Psychiatric Association. https://doi.org/10.1176/appi.books.9780890425787
- Luckasson, R., Borthwick-Duffy, S., Buntinx, W. H., Coulter, D. L., Craig, E. M., Reeve, A., Schalock, R. L., Snell, M. E., Spreat, S., Tassé, M. J., & Verdugo, M. A. (2002). Mental retardation: Definition, classification, and systems of supports (10th ed.). American Association on Mental Retardation.
- Schalock, R. L., Luckasson, R., & Tassé, M. J. (2021). Intellectual disability: Definition, diagnosis, classification, and systems of supports (12th ed.). American Association on Intellectual and Developmental Disabilities.
- Tassé, M. J., Schalock, R. L., Balboni, G., Bersani, H., Buntinx, W. H., Spreat, S., Valenti-Hein, D., & Zhang, D. (2012). The construct of adaptive behavior: Its conceptualization, measurement, and use in the field of intellectual disability. American Journal on Intellectual and Developmental Disabilities, 117(4), 291–303. https://doi.org/10.1352/1944-7558-117.4.291
- Thompson, J. R., Bradley, V. J., Buntinx, W. H., Schalock, R. L., Shogren, K. A., Snell, M. E., Wehmeyer, M. L., Borthwick-Duffy, S., Coulte, D. L., Craig, E. M., Gomez, S. C., Lachapelle, Y., Luckasson, R., Reeve, A., Spreat, S., Tassé, M. J., Verdugo, M. A., & Yeager, M. H. (2009). Conceptualizing supports and the support needs of people with intellectual disability. Intellectual and Developmental Disabilities, 47(2), 135–146. https://doi.org/10.1352/1934-9556-47.2.135