Models of classification for LDs

1. Aptitude-achievement discrepancy 2. Low achievement

3. Intraindividual differences 4. Response to intervention (RTI) 1. Aptitude-Achievement Discrepancy

• Aptitude: composite measure of IQ (or verbal IQ, nonverbal IQ, non-IQ⁶)

• Weak external validity: IQ-achievement discrepancy will not produce differences among subgroups that represent different forms of underachievement.

Cognitive, behavioral and achievement correlates of IQ-discrepancy -> NO significant difference in pattern between low achievement group and IQ-achievement discrepant children

Development (rate of growth over time, level of ability at different age), prognosis, precursors -> NO difference

Intervention outcomes -> NO strong relation, especially NO interaction between effect of intervention and levels of IQ

Neurobiological factors -> NO evidence for differential genetic etiology, or different neuroimaging profiles

• Psychometric factors in discrepancy models:

Regression to the mean

Lower reliability of discrepancy scores

Individuals around the cut-points are too similar 2. Low achievement

• LD identification based on absolute low achievement BUT it means LD = low achievement

• Identification of unexpected underachievement needs additional criteria, which rule out other causes of low achievement (e.g. mental retardation)

• Common practice⁷: IQ in normal range AND achievement score below the cut-point.

• Unique group of underachievers whose low performance is attributed to emotional disturbance, economic disadvantage etc. (e.g. DL)

3. Intraindividual Differences Model

• The person with LDs is one with strengths in many areas but weaknesses in some core cognitive processes that lead to underachievement -> pattern of strengths and weaknesses is used as a marker to identify unexpected underachievement

6"Look for examples of aptitude measures from different domains!"

7"Collect data about local practices"

• Unevenness in development indicated by performance across a battery of cognitive or neuropsychological tests: cognitive assessments can separate underachievement that is due to intrinsic, constitutional factors from underachievement due to social and economic factors.

• Core cognitive processes⁸ in reading, writing, spelling and math (…)

• Screening batteries⁹ to assess core cognitive processes in reading, writing, spelling and math (…) – in kindergarten, and in first and second Grades.

• Using multiple tests at the same time point, looking for recurrent discrepancies in similar tests within a profile -> reliability, BUT measures of processing skills have reliabilities that are lower than norm-referenced IQ and achievement tests

• BUT little evidence: e.g. word recognition problems – phonological awareness and rapid naming of letters also in children who are economically disadvantaged, second language learners or emotionally disturbed

• BUT training cognitive processes (e.g. phonological awareness) in the absence of an emphasis on content (e.g. letter component) doesn’t usually translate into the related academic area (e.g. reading).

• Individuals with increasingly severe academic problems will show increasingly flat profiles on cognitive tasks – most severely impaired are excluded ???

4. RTI Models¹⁰

• Unexpected underachievement = inadequate response to increasingly intense instruction/high-quality intervention that is effective with most individuals.

8"Collect those processes that recent research has shown are relevant to learning academic skills"

9http://www.sedl.org/reading/rad/database.html

10http://www.ritap.org/rti/about/overview.php

• Assessments of learning and progress over time – multiple assessments over time ( <-> status models).

Estimates of growth parameters AND estimate of status: the intercept term in the individual growth model.

• "RTI is the practice of (1) providing high-quality instruction/intervention matched to student needs and (2) using learning rate over time and level of performance to (3) make important educational decisions to guide instruction."

• Requires closer integration of general education and special education: one system, not two – all students are general education students first.

• Classification problems: defining a comparison group, the academic skills/abilities to be evaluated and the criteria for progress. E.g. student must demonstrate a ‘dual discrepancy’ in which slope and final level are both at least 1 SD below those of peers/norm-referenced standard

• Validity: inadequate responders can be clearly differentiated from other low achievers in terms of cognitive correlates, prognosis and neurobiological factors (e.g. predominant right hemisphere activity).

Exclusionary factors

• Exclusionary factors have been a required part of an initial evaluation for special education for a long time, but have often been a mere check box rather than a critical element of the evaluation¹¹.

• Exclusions must be seen as policy-based determinations to facilitate service delivery and to avoid mixing of funds, not as classification factors that have strong validity.

• Different intervention needs? E.g. children whose primary language is a minority language BUT the same interventions promote reading success in economically disadvantaged and DL children.

• Policy decisions: need to avoid the mixing of special education and compensatory education funds (USA¹²): exclusionary criteria are not meant to preclude children from placement…

• Emotional and behavioral difficulties:

• Problem of co-occurring social and emotional problems -> which disorder is primary? E.g. children with LD may develop behavioral difficulties that are secondary to lack of success in school

• Problem of comorbid ADHD -> profile of cognitive performance ADHD+DL , ADHD+DC and DL, DC is different

11"Discuss how the local evaluation addresses this component of an initial evaluation?"

12"Compare and discuss different state policies"

ADHD+DL

ADHD+DC

• Economic disadvantage:

• How race, ethnicity and cultural background might influence school learning¹³ in general and the expression of different types of LDs in particular?

• Children who grow up in economically disadvantaged environments are behind in language development when they enter school. This delay will interfere with the development of reading and math skills.

• Inadequate Instruction:

• Instructional factors are the least frequently examined – but perhaps the most important – exclusionary criteria. Do we have a good understanding of what constitutes adequate instruction?

An integrated model

• U.S. Office of Special Education Programs (2002)

• Comparison of a traditional model and a model based on RTI

13"Look for some research study from your country"

• Three sets of criteria for identifying students with LDs:

Mass screening -> child as "at risk"

Response to instruction: curriculum-based assessments of the academic domain of concern AND evaluation of the quality of the instruction -> if inadequate response

Level of achievement: norm-referenced assessments (verifying findings from curriculum-based assessments and all academic domains evaluated) -> if low achievement

Comprehensive evaluation that extends beyond the evaluation of the achievement domain: comorbid conditions (parent and teacher rating scales), causes of underachievement (home, language, social factors AND cognitive assessments = intraindividual perspective

• More details [http://pszichologia.elte.hu/eltetamop412A1/soced/III_LD_7.pdf]