Core Principles: Evaluation and Identification of Learning Disabilities

Evaluation and Identification of Learning Disabilities

Accurate identification through a thorough evaluative process, is the first step to ensure that individuals with Learning Disabilities[i] receive the services, supports and accommodations that are required for academic and life success. It is the position of the Learning Disabilities Association of America that the domains discussed below, must be assessed as part of a thorough evaluation for potential Learning Disabilities.

Learning Disabilities range in severity and interfere with the acquisition and use of one or more of the following:  oral language– listening, speaking, understanding; reading– decoding, phonetic knowledge, word recognition, fluency and comprehension; writing – written expression, spelling, fluency; mathematics– computation, problem solving, math fluency. It is necessary that any evaluation for suspected Learning Disabilities thoroughly assesses all areas of potential skill deficiency as well as the underlying cognitive and psychological processes contributing to learning.

There is increasing scientific evidence of the genetic basis[ii] of Learning Disabilities. Thus, whenever possible, evaluation must start with a detailed developmental history. This history must not just consider the child’s own development of language and pre-reading skills but also seek out information about the acquisition of language and academic skills of the individual’s family members.  Additionally, medical information must be obtained from the parent or school in order to make differential diagnostic decisions.  Medical information must include hearing, vision, or motor difficulties that could be contributing to the acquisition of academic skills.

Multiple sources of data are needed to conduct an ecologically valid evaluation to determine the presence of a Learning Disability.  In addition to standardized, norm-referenced assessments of cognitive abilities and academic achievement, an evaluation of Learning Disabilities must include data when available from criterion referenced and curriculum-based assessments, progress monitoring data pertaining to the student’s response to evidence-based[iii],[iv] interventions targeting specific academic deficits, and informal teacher designed assessments. Parent, teacher and student input and observations should be obtained via interview and/or questionnaires that assess behavioral, social/emotional functioning and attention/executive functioning.

Cognitive processing deficits are agreed to be a hallmark of Learning Disabilities; therefore, it is essential that processing abilities associated with the acquisition and use of skill sets involving oral language, reading, writing and math, be assessed using valid and reliable instruments. The model of the structure of the intellect that is widely accepted by researchers and practitioners in the field, is the Cattell-Horn-Carroll Theory (CHC). Most of the major assessments of cognitive ability have been revised or developed in accordance this theory[v]. Assessments based on this theory measure broad and narrow cognitive processes that have been found to be critical in the acquisition of academic skills. Some of these processes are working memory and long-term retrieval, orthographic processing, auditory processing skills, visual-spatial processing, processing speed, fluid reasoning, and verbal abilities.

Functional academic demands vary across the lifespan as well as across educational settings. When an individual does not need support in one setting or at one time of life, it does not necessarily mean that support is not warranted at another time or in another context. An evaluation must be thorough enough to anticipate these changing demands and underscores the need for evaluation of the specific demands of the learning environment in addition to the learner.

Underachievement is a symptom of the presence of a Learning Disability but is not sufficient as a sole criterion for identification. Evaluation for Learning Disabilities must always evaluate the relative contribution of other factors that may result in academic achievement below the levels expected based on the individual’s age, grade and other abilities.  A Learning Disability must not be primarily due to visual, hearing or motor disability, intellectual disability, emotional or behavioral disability, cultural factors, environmental or economic factors, limited English proficiency and lack of adequate instruction. However, the presence of factors on this list does not preclude the existence of a learning disability.

Cognitive ability assessments can be used to rule out the presence of an intellectual disability as the cause of underachievement. Underachievement that is due to lack of instruction, limited English language proficiency, or socioeconomic disadvantage is better evaluated by assessing the individual’s response to evidence-based instruction and intervention, as well as conducting a detailed developmental and social history.  An underlying assumption in the evaluation of Learning Disabilities is that vision and hearing difficulties have been ruled out or their impact is differentially considered when assessing the level of academic impairment (i.e., a sensory-based deficit can co-occur with a Learning Disability).

When evaluating for Learning Disabilities, it is not sufficient to simply collect data. Identification of Learning Disabilities requires clinical analysis of the data collected which includes synthesizing qualitative and quantitative information by a qualified professional trained in human development, learning theory, assessment, developmental disabilities, neuropsychology, etc. Identification involves more than formulaic analyses of scores such as in discrepancy models or calculation of Rate of Improvement in Response to Intervention models. It is essential to consider qualitative factors and process factors involved in reaching what may quantitatively be an “average” test score.  This type of qualitative analysis requires clinical training and judgment. In the school setting, this clinical analysis is the purview of school psychologist and other qualified professionals, focusing on the manner in which processing deficits are impacting learning. Additional qualified professionals[vi] may contribute to analysis within an occupational setting.

The analysis of data collected through the evaluation process described here, and the recommendations that follow from the evaluation, must always relate back to how the individual functions in the classroom or other learning environment. When cognitive processing deficits impair one’s acquisition of skills and ability to navigate learning and/or performance demands within an educational or occupational environment, identification of a Learning Disability is warranted.


[i] “Learning Disabilities refer to a number of disorders which may affect the acquisition, organization, retention, understanding or use of verbal or nonverbal information. These disorders affect learning in individuals who otherwise demonstrate at least average abilities essential for thinking and or reasoning.  As such, learning disabilities are distinct from global intellectual deficiency.  Learning disabilities result from impairments in one or more of the basic processes related to perceiving, thinking, remembering or learning. These include, but are not limited to : language processing, phonological processing, visual spatial processing, processing speed, memory, attention and executive functions…”   (Core Principles, LDA February 2018)

[ii] Numerous studies support the genetic basis of learning disabilities. See Berninger, Virginia, and Todd Richards. “Inter-relationships among behavioral markers, genes, brain and treatment in dyslexia and dysgraphia.” Future Neurology, vol. 5, no. 4, 2010, p. 597 and Hensler, B., et. al. “Behavioral genetic approach to the study of dyslexia”. Journal of Developmental & Behavioral Pediatrics Volume 31(7), September 2010, pp 525-532

[iii] Evidence-based instruction is an instructional approach, practice, or methodology that is derived from evidence. Such evidence is often a derivative of empirical research, resulting in reliable, trustworthy, and valid substantiation suggesting that a program or practice is effective and that all proofs or facts that support such a program or practice are scientifically based. Professional wisdom, based on educators’ individual experiences and consensus, also provides a source of evidence. (Whitehurst, G. J. (2002). Evidence-based education (EBE). Retrieved from

[iv] RTI data should be used when appropriate and available. For example, RTI data is not relevant in the evaluation of older students and adults. Additionally, evaluation for an individual thought to have a learning disability should never be delayed in order to implement an RTI process.

[v] Schneider, J. W. & McGrew, K. S., The Cattell-Horn-Carroll Theory of Cognitive Abilities. Pp 73-94 in Flanagan, D. P. & McDonough, E.M. (2018) Contemporary Intellectual Assessment, Fourth Edition: Theories, Tests, and Issues, edited by Dawn P. Flanagan, and Erin M. McDonough, Guilford Press.

[vi] Qualified Professional” is never specifically defined in the federal laws or regulations, however in its comments accompanying the published regulation the Department of Justice refers to “a professional with expertise relating to the disability in question” as the person qualified to make an individual assessment. 28 CFR Pt.. 36, App A, Ch 1, p. 785 (7-1-12 Edition). Examples of qualified professionals include school, clinical and neuropsychologists; medical professionals; speech and language pathologists, occupational therapists; and others with advanced specialized training.

Download the PDF of this Core Principle here.

Based on the purpose of the Learning Disabilities Association of America to create opportunities for success for all individuals affected by learning disabilities through support, education and advocacy, LDA’s Core Principles were developed and approved by the Board of Directors of LDA to establish a set of standards and guidelines reflecting the positions and philosophies of our organization.

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