Identification

Aligned with the definition of ID shared in the prior section, most schools and professional organizations use IQ tests to assess intelligence and adaptive behavior protocols. These data are then used together to determine whether one has an ID. The following IQ classifications are used to group people with intellectual disabilities in ways that support program design: mild (IQ score of 35–50), severe (IQ score of 20–35), and profound (IQ score below 20). Notably, 89% of those diagnosed with an ID fall into the mild and moderate categories (Vaughn & Bos, 2020). However, IQ tests have had a history of being disputed when used in decision-making. Thus, the following cautions are essential to consider whenever one uses IQ tests for decision-making: (1) an individual’s IQ score can change;  (2) the younger the child, the less valid the results; and (3) the ability to live a fulfilling life does not rest solely on an IQ score.

Further, much of the recent criticism about IQ scores is connected to them being fundamentally flawed, as they do not consider the complex nature of the human intellect, its different components, and the impact of lived experiences. Critics point out that most intelligence tests are concerned with only a narrow set of skills and may measure nothing more than the ability to take tests. Critics also maintain that the content and administration of IQ tests negatively impact students from historically oppressed groups; because the tests are shaped by the values of Western middle-class culture, the results are often used to label students, which has disproportionately impacted marginalized students. Finally, IQ tests do not offer information on motivation, emotion, attitudes, and other similar factors that may strongly affect a person’s success in school and life (Shuttleworth-Edwards, 2016).

Adaptive behavior measures usually involve a caregiver, teacher, or other professionals who answer questions via a checklist or semi-structured interview regarding an individual’s independence, daily living skills, and behaviors. Factors to consider include the ability to comprehend and participate in a conversation, understand and follow social norms, and perform activities such as getting dressed and using the restroom. These measures are also prone to bias because some professionals do not understand other cultures (Vaughn & Bos, 2020).

Federal

Intellectual disability is defined as “significantly subaverage general intellectual functioning, existing concurrently [at the same time] with deficits in adaptive behavior and manifested during the developmental period, that adversely affects a child’s educational performance” (IDEA, 2004). Again, this definition has two key components: a student’s IQ and the capability to function independently, usually called adaptive behavior.

Minnesota

As articulated earlier, the legislature in Minnesota continues to use the term DCD rather than ID. For students to receive special education services in Minnesota under the DCD disability category, the legislature added protections beyond what is written in IDEA. These protections are designed partly to address trends which indicate that students of color and economically disadvantaged students are overrepresented in the ID population nationally and in Minnesota (Vaughn & Bos, 2020). To illustrate, Black or African American students are twice as likely to be identified as having an ID, compared to all other racial/ethnic groups combined. Indigenous students are impacted similarly. This disparity also holds for these groups in Emotional/Behavioral Disabilities and Learning Disabilities, as all three disability areas are arguably most reliant on clinical judgment for identification. Thus, they are also the most prone to examiner bias.

As a result, per the Minnesota Revisor (2007), students in Minnesota must meet the federal criteria plus the following…

“Developmental cognitive disability (DCD)” means a condition resulting in significantly below-average intellectual functioning and concurrent deficits in adaptive behavior that adversely affects educational performance and requires special education and related services. DCD does not include conditions primarily due to sensory or physical impairment, traumatic brain injury, autism spectrum disorders, multiple severe impairments, cultural influences, or inconsistent educational programming.

The team shall determine that a pupil is eligible as having a DCD and needs special education instruction and related services if the pupil meets the criteria in items A and B.

1. The pupil demonstrates below-average adaptive behavior in school, home, and, if appropriate, community environments. For this item, “below average” means:

(1) a composite score at or below the 15th percentile (approximately 70 or lower) on a nationally normed, technically adequate measure of adaptive behavior; and

(2) documentation of needs and the level of support required in at least four of the seven adaptive behavior domains across multiple environments. Systematic observation and parent input must be included as sources to document the need and level of support. All of the following adaptive behavior domains must be considered:

(a)        daily living and independent living skills;

(b)       social and interpersonal skills;

(c)        communication skills;

(d)       academic skills;

(e)        recreation and leisure skills;

(f)        community participation skills; and

(g)       work and work-related skills.

Other sources of documentation may include checklists; classroom or work samples; interviews; criterion-referenced measures; educational history; medical history; or pupil self-report.

1. The pupil demonstrates significantly below average general intellectual functioning measured by an individually administered, nationally normed test of intellectual ability. For this subitem, “significantly below average general intellectual functioning” means:

(1) mild-moderate range: two standard deviations below the mean, plus or minus one

standard error of measurement; and

(2) severe-profound range: three standard deviations below the mean, plus or minus one

standard measurement error.

Significantly below-average general intellectual functioning must be verified through a written summary of results from at least two systematic observations with consideration for culturally relevant information, medical and educational histories, and one or more of the following: supplemental tests of specific abilities, criterion-referenced tests, alternative methods of intellectual assessment, clinical interviews with parents, including family members, if appropriate, or observation and analysis of behavior across multiple environments.