2.4 Achievement & Diagnostic Processing Assessment
Key Takeaways
IDEA lists eight areas in which SLD can be found: oral expression, listening comprehension, written expression, basic reading skill, reading fluency skills, reading comprehension, mathematics calculation, and mathematics problem solving (34 CFR § 300.309(a)(1)).
Individually administered achievement batteries such as the WIAT-4, KTEA-3, and WJ IV or WJ V Achievement cover these areas with norm-referenced subtests.
Norm-referenced tests compare a student with peers; criterion-referenced tests compare performance with a skill standard; both answer different questions.
The CTOPP-2 measures phonological awareness, phonological memory, and rapid naming, which are central to diagnosing word-reading problems such as dyslexia.
Executive function rating scales (e.g., BRIEF-2) and performance tests measure different aspects of executive function and often correlate only weakly.
Two Different Questions
The ETS outline distinguishes measures of educational achievement from diagnostic and processing measures (examples given: memory, executive functioning, phonemic awareness). An achievement test answers what the student can do in reading, writing, and math relative to peers. A diagnostic measure helps explain why: which underlying skill or process is limiting progress. Both inform intervention, and both are interpreted within the full data set, never alone.
IDEA's Eight Achievement Areas for SLD
Under 34 CFR § 300.309(a)(1), a team may find a specific learning disability when a child does not achieve adequately for age or grade-level standards in one or more of these areas:
| Area | What an Assessment Might Include |
|---|---|
| Oral expression | Formulating sentences, retelling, expressive vocabulary |
| Listening comprehension | Following oral directions, understanding spoken passages |
| Written expression | Sentence construction, organization, spelling and mechanics in context |
| Basic reading skill | Word reading, decoding of pseudowords |
| Reading fluency skills | Rate and accuracy of connected-text reading |
| Reading comprehension | Understanding passages; literal and inferential questions |
| Mathematics calculation | Computation, math fact fluency |
| Mathematics problem solving | Applied problems, word problems, quantitative reasoning |
A comprehensive achievement evaluation samples the areas related to the referral concern and uses more than one source, such as standardized scores, CBM, classroom work, and state tests.
Individually Administered Achievement Batteries
| Battery | Notes |
|---|---|
| Wechsler Individual Achievement Test, Fourth Edition (WIAT-4) | Published 2020; wide age range (about 4 through 50); reading, writing, math, oral language, and dyslexia-related subtests; linked to the WISC-V for ability–achievement comparisons |
| Kaufman Test of Educational Achievement, Third Edition (KTEA-3) | Reading, math, written language, and oral language composites; detailed error analysis |
| Woodcock-Johnson Tests of Achievement (WJ IV ACH; WJ V released 2025) | Co-normed with the WJ cognitive and oral language batteries, which supports comparisons among ability, achievement, and oral language |
| Group-administered and computer-adaptive tests | State assessments and district benchmarks; useful for screening and trend data, not for detailed diagnosis |
Norm-Referenced vs. Criterion-Referenced Measurement
| Feature | Norm-Referenced | Criterion-Referenced |
|---|---|---|
| Compares the student with | A representative peer group | A defined standard of mastery |
| Scores | Standard scores, percentiles | Percent correct, mastered/not mastered |
| Best for | Eligibility, comparing with peers, identifying relative weakness | Instructional planning, checking mastery of specific skills |
| Limitation | Few items per skill; limited instructional detail | No information about standing relative to peers |
Many real decisions need both: a norm-referenced score to show the severity of the gap, and criterion-referenced or error-analysis data to decide what to teach.
Test Selection Checklist
- Norms: Recent and representative of the student (NASP Standard II.3.4 calls for norms that are representative, recent, and appropriate, and for using the most current version of published instruments).
- Floors and ceilings: A test with a weak floor cannot distinguish among very low performers, and a weak ceiling cannot distinguish among very high performers. Check that the student's likely performance level has enough items.
- Item gradients: Steep jumps in difficulty between items make small changes in raw score produce large changes in standard score.
- Reliability high enough for the decision (about .90 or higher for important individual decisions; see Section 2.1).
- Fit with the referral question: A student referred for reading fluency needs a timed connected-text measure, not only untimed word reading.
Diagnostic and Processing Measures
Phonological Processing
The Comprehensive Test of Phonological Processing, Second Edition (CTOPP-2) measures phonological awareness (blending, elision, sound matching), phonological memory (memory for digits and nonwords), and rapid naming (rapid symbolic and non-symbolic naming). Weak phonological awareness and slow rapid naming are strongly associated with word-reading difficulties. Students with both weaknesses, sometimes called a double deficit, tend to have more severe reading problems.
Memory and Learning
Batteries such as the Wide Range Assessment of Memory and Learning, Third Edition (WRAML-3) assess verbal and visual memory, immediate and delayed recall, and working memory. Memory findings matter when a student learns material but cannot retain it, or struggles with multi-step directions.
Executive Functioning and Attention
- Rating scales such as the Behavior Rating Inventory of Executive Function, Second Edition (BRIEF-2) ask parents, teachers, and students about everyday inhibition, shifting, emotional control, working memory, planning, and organization.
- Performance tests such as the Delis-Kaplan Executive Function System (D-KEFS) measure executive skills in a structured testing session.
- Continuous performance tests measure sustained attention and impulsive responding on a computer task.
Ratings and performance tests often correlate only weakly. Ratings capture how executive skills work in everyday settings; performance tests capture what the student can do under optimal, structured conditions. A student may do well in the quiet testing room yet struggle in a noisy classroom. That difference is information, not a contradiction.
Other Diagnostic Areas
- Language: Comprehensive language batteries (often given by the speech-language pathologist) separate receptive, expressive, and pragmatic language problems from reading problems.
- Visual-motor integration: Measures such as the Beery-Buktenica Developmental Test of Visual-Motor Integration inform handwriting and copying concerns, usually with occupational therapy input.
- Error analysis: Miscue analysis in reading, spelling error patterns, and math error types turn scores into teaching targets.
Interpreting Achievement and Processing Data Together
- Confirm the academic deficit with more than one source (standardized scores, CBM, classroom work).
- Link any processing weakness logically and empirically to the academic weakness (for example, phonological awareness to decoding; see the processing links table in Section 2.3).
- Check exclusionary factors such as vision, hearing, motor problems, intellectual disability, emotional disturbance, cultural factors, environmental or economic disadvantage, and limited English proficiency (34 CFR § 300.309(a)(3)).
- Translate findings into instruction. A diagnostic profile is valuable only if it changes what the teacher does.
Exam Scenario Pattern
When an item describes a student who reads slowly and inaccurately, has trouble blending sounds, and names familiar letters slowly, the best diagnostic choice is a phonological processing measure (such as the CTOPP-2) plus timed word and passage reading, not a projective test or an adaptive behavior scale.
A third grader reads slowly and inaccurately, has difficulty blending and segmenting sounds, and is slow to name familiar letters. Which additional measure would best clarify the underlying problem?
A projective drawing task to assess emotional contributors to reading avoidance.
An adaptive behavior scale completed by the parent.
A measure of phonological processing, such as the CTOPP-2, including phonological awareness and rapid naming.
A group-administered state reading test from the previous spring.
A school psychologist is choosing a test to measure very low math skills in a fifth grader who currently performs near a first-grade level. Which technical property deserves the closest attention?
The test ceiling, because the student may answer too many difficult items correctly.
The test's ceiling rules for gifted students.
Whether the test yields grade equivalents.
The test floor, because the test must contain enough easy items to distinguish among very low performers.
Under IDEA, which of the following is one of the eight areas in which a team may find a specific learning disability?
Visual-motor integration
Processing speed
Mathematics problem solving
Executive functioning
Sections you finish are checked off in the contents.