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The SAGE Encyclopedia of Educational
Research, Measurement, and Evaluation
Learning Disabilities
Contributors: Jessica Namkung & Peng Peng
Edited by: Bruce B. Frey
Book Title: The SAGE Encyclopedia of Educational Research, Measurement, and Evaluation
Chapter Title: "Learning Disabilities"
Pub. Date: 2018
Access Date: April 6, 2018
Publishing Company: SAGE Publications, Inc.
City: Thousand Oaks,
Print ISBN: 9781506326153
Online ISBN: 9781506326139
DOI: http://dx.doi.org/10.4135/9781506326139.n385
Print pages: 954-956
©2018 SAGE Publications, Inc.. All Rights Reserved.
This PDF has been generated from SAGE Knowledge. Please note that the pagination of
the online version will vary from the pagination of the print book.
Under the Individuals with Disabilities Education Act, (IDEA), the term specific learning
disability is defined as a specific disorder in one or more areas of psychological processes
involved in understanding and using spoken or written language, which results in deficits in
the ability to listen, think, speak, read, write, spell, or do mathematics. Specific learning
disability, also referred to as specific learning disorder, does not include learning problems
that are attributable to sensory disorders, emotional disturbance, intellectual disabilities, or
cultural or economic disadvantages. Today, learning disabilities account for as much as 50%
of all students receiving special education. This entry first discusses the causes of and
identification of learning disabilities. It then describes the characteristics of students with
learning disabilities and types of learning disabilities. Finally, it looks at instructional strategies
that are thought to be effective with students with learning disabilities.
Although a single cause of a learning disability is not known, the possible causes include
physiological factors (e.g., heredity, brain injury, and biochemical imbalance) and
environmental factors (e.g., poor nutrition and exposure to environmental toxins, such as
lead). Students with learning disabilities are a heterogeneous group, meaning that they may
have problems in reading, mathematics, written language, or oral language.
Identification of Learning Disabilities
IQ-Achievement Discrepancy
Traditionally, learning disabilities are identified based on the discrepancies between a
composite measure of IQ and academic achievement, such as mathematics achievement.
That is, if students show at least a two standard deviation difference between their
intelligence, indexed by an IQ test, and academic ability, indexed by an academic
achievement test, the students are identified as having a learning disability. Thus, a student
who exhibits unexpected learning difficulties as indicated by academic achievement far below
what would be expected by the IQ score (e.g., average IQ score of 100 and below-average
reading achievement score of 70) would be identified as having a learning disability. On the
other hand, a student with a below-average IQ score of 85 and a below-average mathematics
achievement score of 80 would not be identified as having a learning disability because there
is not a large enough discrepancy.
The IQ-achievement discrepancy model has been often criticized for being a wait-to-fail
model. That is, students are not identified as having learning disabilities until there are
substantial differences between their IQ and achievement scores, thereby delaying early
intervention opportunities. This model also does not assess or inform the quality of instruction
received by students, thereby not allowing discrimination between those who are low
achievers as a result of poor instruction and those with true learning disabilities.
Response to Intervention
As an alternative to the IQ-achievement discrepancy model, response to intervention is a
three-tier approach to providing high-quality, research validation instruction with ongoing
progress monitoring and data-based decision making. In general, all students are given a
universal screening measure at the beginning of the year to identify those who are at risk. In
Tier 1, teachers provide evidence-based instruction in the general education, whole-class
setting and monitor student progress on a weekly basis. Students who do not make adequate
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progress (generally around 20–30% of students) move to the more intensive level. In Tier 2,
students receive additional support, such as targeted interventions, in a small-group setting
(three to five students) from either the general classroom teacher or other educational
personnel, such as a reading specialist, special education teacher, or tutor. Student progress
is monitored continuously throughout. Those who make adequate progress may return to Tier
1 or continue to receive Tier 2 instruction, and those who still do not make sufficient progress
in Tier 2 move to the most intensive level (5–10% of students).
In the most intensive level, Tier 3, students receive even more differentiated and individualized
support, preferably in a one-on-one setting. At this stage, students may be identified with a
learning disability and qualify for special education services. In this way, response to
intervention is based on a preventive framework by providing increasingly more intensive
instruction to help struggling learners early on before they fall too far behind their peers and
before they are identified as having learning disabilities.
Characteristics of Students With Learning Disabilities
Although students with learning disabilities have average to above-average intelligence, they
show deficits in cognitive abilities, such as attention, working memory, long-term memory, and
processing speed, compared to their typically developing peers. For example, students with
learning disabilities have significant difficulty attending to classroom instruction and ignoring
other stimuli (e.g., auditory and visual) in the classroom. In fact, a significant number of
students with learning disabilities have co-occurring attention-deficit/hyperactivity disorder.
Students with learning disabilities show weaknesses in memory. In particular, students with
learning disabilities have poor working memory, which refers to the ability to simultaneously
process and store information to support ongoing cognitive tasks (e.g., keeping track of the
contents of the text just read while processing new text when reading a story), and long-term
memory, which refers to the permanent storage of information in the brain (e.g., automatically
recalling 5 + 2 = 7 from memory without having to count up).
Students with learning disabilities also show weakness in information processing. They tend
to be slower at processing words or numbers and executing multiple steps compared to
typically developing peers. They also have difficulty with metacognition, lacking the ability to
relate what they have learned to new information they are learning. Besides the cognitive
difficulties, students with learning disabilities tend to have lower self-esteem, likely to be due
to repeated academic failure they experience, poor social skills, and lower motivation
compared to their typical peers.
Types of Learning Disabilities
Reading Disabilities
It is estimated that reading disabilities is the most prevalent type of learning disabilities. As
many as 90% of school-aged children with learning disabilities have reading disabilities, and
even the low estimates are approximately 60%. The most common subtypes are dyslexia,
specific comprehension problems, or a combination of dyslexia and specific comprehension
deficits.
Students with dyslexia are characterized by having difficulties in recognizing words accurately
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and Evaluation
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and fluently but having language comprehension abilities appropriate for their age level.
Those with dyslexia have deficits in phonological awareness, the ability to understand that
speech flow can be broken into smaller sound units, such as words, syllables, and phones.
These deficits, in turn, lead to word recognition problems. On the other hand, students with
specific comprehension deficits have no problems in recognizing words accurately and
fluently but have difficulties in language comprehension skills, such as vocabulary and
listening comprehension. These difficulties may stem from broad language difficulties that are
present before developing reading skills, such as weak vocabulary knowledge, difficulty
processing grammar, and poor oral language comprehension. The combination of dyslexia
and specific comprehension deficits is characterized by difficulty in word recognition skills as
well as language comprehension skills. It is estimated that 5–17% of the population has
dyslexia, and 10–15% of primary school-aged students have specific reading comprehension
deficits.
Mathematics Disabilities
Students with mathematics learning disabilities constitute approximately 5–8% of the school-
aged population. It is estimated that approximately 40% of students with learning disabilities
have mathematics disabilities. The two most common deficit students with mathematics
learning disabilities experience are computations and problem solving.
Computations include number combinations (e.g., 3 + 4 = 7) and procedural computations
(e.g., 16 + 28 = 44), in which students find the answer to already setup problems. Students
with mathematics learning disabilities are slower at counting to figure out the answers, rely on
inefficient counting strategies, such as finger counting and counting all (counting 1, 2, 3, 4, 5,
6, 7 for 3 + 4 = 7), and have difficulty automatically recalling number combinations from long-
term memory. By contrast, problem solving refers to the thinking required to solve word
problems, which require students to understand the problem narrative, identify missing
information, construct a number sentence, and solve for the missing information to find the
answer. Because of the combination of language requirements and complex processes
involved in problem solving, problem solving is the most difficult area of mathematics for many
with learning disabilities.
Written Expression Disabilities
Students with written expression disabilities have a particular difficulty communicating through
writing. Although the prevalence of written expression disabilities has not been well studied
and varies greatly across studies (1–20%), it is estimated that at least 10% of school-aged
children may be affected given the high rates of reading disabilities (10–15%) and language
disorders (8–15%). Those with written expression disabilities have deficits in many related
abilities required in writing, such as grammar and punctuation. Common deficits are in
handwriting, spelling, and composition. Students with written expression disabilities often
have poor handwriting; handwriting requires the knowledge of orthography and planning
ability as well as motor skills. Students with written expression disabilities also experience
difficulty with spelling, which requires integration of visual processing, phonological or
orthographic representations, and motor skills. Difficulties with composition involve problems
with organization, coherence, clarity, and revision processes.
Instructional Strategies
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and Evaluation
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Explicit Instruction
Explicit instruction is a systematic instructional approach, in which the teacher directly shares
the information students need to learn using concise and specific language, but is also
didactic in that there is a high level of teacher and student interaction. Explicit instruction
involves a focused lesson, in which complex skills are broken down into smaller, targeted
parts, a clear explanation of the targeted skill, teacher-led step-by-step demonstrations (I do),
guided practice (we do) with corrective feedback, and independent practice (you do) with
immediate feedback.
Strategy Instruction
Strategy instruction focuses on teaching rules and techniques that guide students to learn
new skills, complete tasks independently, recall the skills later, and apply/generalize the skills
in new settings and situations. This is particularly effective for students with learning
disabilities because they often do not develop efficient learning strategies on their own.
Strategy instruction includes instruction for more broad domains, such as teaching study
skills (e.g., note taking, summarizing, and self-questioning) and mnemonics to assist with
remembering and recalling a specific strategy, and academic content-specific strategies, such
as using self-regulated strategy development to improve writing.
Scaffolding Instruction
Scaffolding refers to the process through which a teacher adds support for students in
mastering tasks. The teacher systematically builds on students’ experience and prior
knowledge when teaching a new skill, then removes the support gradually as students
become more proficient. Content scaffolding refers to choosing content that is not too difficult
or unfamiliar for students learning a new skill, whereas material scaffolding refers to the use
of written prompts or cues to guide students to perform a task independently. In task
scaffolding, a teacher specifies steps in a task and models the steps by verbalizing thought
processes, followed by student practice. During task scaffolding, the teacher gradually
releases the responsibility of completing the task to the students.
See alsoAbility-Achievement Discrepancy; Response to Intervention; Special Education
Identification; Special Education Law
Jessica NamkungPeng Peng
http://dx.doi.org/10.4135/9781506326139.n385
10.4135/9781506326139.n385
Further Readings
Fletcher, J. M., Lyon, G. R., Fuchs, L. S., & Barnes, M. A. (2006). Learning disabilities: From
identification to intervention. New York, NY: Guilford Press.
Fuchs, D., & Fuchs, L. S. (2006). Introduction to response to intervention: What, why, and
how valid is it? Reading Research Quarterly, 41, 93–99.
Geary, D. C. (2004). Mathematics and learning disabilities. Journal of Learning Disabilities, 37,
4–15.
Graham, S., Harris, K. R., MacArthur, C. A., & Schwartz, S. (1991). Writing and writing
instruction for students with learning disabilities: Review of a research program. Learning
Disability Quarterly, 14, 89–114.
National Reading Panel. (2000). Report of the national reading panel: Teaching children to
read: An evidence-based assessment of the scientific research literature on reading and its
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Copyright © 2018 by SAGE Publications, Inc.
The SAGE Encyclopedia of Educational Research, Measurement,
and Evaluation
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implication for reading instruction. National Institute of Child Health and Human Development,
National Institutes of Health.
Swanson, H. L. (1999). Instructional components that predict treatment outcomes for students
with learning disabilities: Support for a combined strategy and direct instruction model.
Learning Disabilities Research & Practice, 14, 129–140.
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and Evaluation
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