What is a Learning Difference?

Understanding the Definition(s)

This question is more complicated than in may seem at first glance, partially because there is not a universal agreement on how to define a learning disability. To further confuse the matter, the terms used to describe differences in learning change depending on how you are defining it. Under special education law (IDEA, 2004), the term used is a Specific Learning Disability, while diagnostically (DSM-5-TR), the term used is a Specific Learning Disorder.

Under IDEA (2004), a student may meet criteria for a Specific Learning Disability in reading (e.g., basic reading skills, reading fluency, reading comprehension), writing (e.g., written expression), mathematics (e.g., math calculation skills, math problem solving), or oral expression. Under the DSM-5-TR, three specific learning disorders – impairment in reading, impairment in written expression, and impairment in mathematics are described. The category of reading is further divided into word reading accuracy, reading rate, and fluency and reading comprehension. The category of written expression is divided into spelling accuracy, grammar and punctuation accuracy, and clarity and organization of written expression. Mathematics is divided into number sense, memorization of arithmetic facts, accurate or fluent calculation, and accurate math reasoning.

Astute observers will note that the terms dyslexia, dyscalculia, and dysgraphia are not noted above. These were terms that were utilized in the prior edition of the diagnostic manual (DSM-IV), but is still referenced under definitions in IDEA (2004) in Section 1401(30)(B).

These terms may still be used by educators, psychologist, or other educational evaluators, however, public understanding of these terms may differ from clinical definitions. Dyslexia originates from the Greek “dys” (“difficulty” or “impaired”) and “lexis” (“word” or “speech”) [similarly “calculia” (“calculation” or “counting”) and “graphia” (“writing”)]. These words were never meant to imply why the individual was struggling to read (or do math, or write), although dyslexia in common parlance seems to have taken on the meaning for deficits in word decoding.

The Discrepancy Model

While cognitive (intelligence) tests are generally pretty good at predicting overall academic achievement, one way of historically defining a learning disability is showing a discrepancy between the overall cognitive score and aspects of academic achievement. This model is not as good at identifying individual aspects of academic achievement (e.g., reading, written expression, mathematics). An additional problem with the discrepancy model is a question of ‘how large a discrepancy,’ as there is no prescribed amount. While some districts or psychologists may indicate that 10-standard score points constitute a discrepancy, others may argue that it needs to be a standard deviation (i.e., 15-points), or even a standard deviation and a half (i.e., 23-points). Differences between districts’ or psychologists’ perceptions of the amount that the score needs to be discrepant with change the prevalence rates of the learning disabilities. The discrepancy model, alone, does not speak to why the discrepancy exists.

Patterns of Strengths and Weaknesses

Based on research, we know that certain cognitive abilities are stronger predictors of academic achievement (e.g., one’s visual-spatial processing ability is superior to one’s verbal reasoning ability at predicting mathematics achievement). The Patterns of Strengths and Weaknesses analysis seeks to utilize composite scores within cognitive assessments as predictors of academic achievement domains.

Response to Instruction & Intervention (RtI) Model

The RtI Model utilizes different tiers of instruction and interventions to attempt to meet the academic needs of students. All students receive a Tier 1 (Universal) intervention, which is the standard instruction administered at grade-level. If students are unable to successfully achieve at this level, they are moved to Tier 2 (Targeted Interventions) or Tier 3 (Intensive Interventions) supports, which generally increase the intensity of the intervention as well as change other factors (e.g., the class-size, instructional curriculum, etc.). Critics of RtI have described this intervention as a ‘wait to fail’ model, whereby students are only moved to higher tiers of support if they do not make appropriate progress at lower levels. Students can meet criteria for a learning disability if they continue to fail to progress given greater levels of support.

Multi-Tiered Systems of Support (MTSS) Model

This framework is aimed at providing academic and behavioral support to all students, including those with diverse learning needs. It utilizes a model similar to RtI, but also focuses on increasing behavioral supports based on individual student need.