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Wechsler Individual Achievement Test-III (WIAT-III)

For more information please visit: Wechsler Individual Achievement Test-III

Supplemental : Congenital Muscular Dystrophy (CMD).
Short Description of Instrument
The Wechsler Individual Achievement Test–III (WIAT-III) is a standardized academic achievement test used to measure previously learned knowledge in the areas of Reading, Written Language, Mathematics, and Oral Language. The scores are based on age norms. A description of each test, scores reported in Standard Scores (SS) and Percentile Rank (PR), and observations made by the examiner during testing are reported below.
SS                    PR                   Classification
131-above      98                    very superior
121-130          92-97              superior
111-120          76-91              high average
90-110            25-75              Average
80-89              9-24                 low average
70-79              3-8                   Low
69-below        0.1-2               very low    
Sub-tests and Observations:
The WIAT – III includes the following sub-tests and observations:
    • Early Reading Skills – measures several skills deemed important for developing reading skills.
    • Word Reading – is designed to measure speed and accuracy of single word reading.
    • Pseudo-word Decoding – measures speed and accuracy of decoding skills.
    • Reading Comprehension – measures literal and inferential reading comprehension skills using a variety of passage and question types that resemble those used in a school setting.
    • Oral Reading Fluency – measures oral reading fluency of expository and narrative passages.
    • Total Reading– includes Word Reading, Pseudoword Decoding, Reading Comprehension, and Oral Reading Fluency.
    • Basic Reading – includes Word Reading and Pseudoword Decoding.
    • Reading Comprehension and Fluency – includes Reading Comprehension and Oral Reading Fluency.
    • Numerical Operations – measures written mathematics calculation skills under untimed conditions.
    • Math Problem Solving – measures the ability to problem solve mathematically using both verbal and visual prompts.
    • Math Fluency – these subtests are designed to measure written mathematics calculation fluency, accuracy and speed.
    • Alphabet Writing Fluency – measures ability to write alphabet letters within a 30 second time limit.
    • Spelling – measures the ability to spell dictated letters, blends, and words.
    • Sentence Composition – includes sentence combining and sentence building components which measure sentence formulation skills, including the use of morphology, grammar, syntax, semantics and mechanics.
    • Essay Composition – measures spontaneous written expression in response to a prompt under timed conditions.
    • Writing Expression – includes Alphabet Writing Fluency, Spelling, Sentence Composition, and Essay Composition.
    • Listening Comprehension – contains receptive vocabulary and oral discourse comprehension components and measures listening comprehension at the level of the word, sentence and discourse.
    • Oral Expression – contains expressive vocabulary, oral word fluency, and sentence repetition components and is designed to measure skills and competencies that are important for effective speaking vocabulary, word retrieval, flexibility of thought process, and oral syntactic knowledge and short-term memory.
    • Oral Language – includes Listening Comprehension and Oral Expression.

The WIAT is commonly used in clinical psycho-educational and neuropsychological evaluations and in research across populations.
Administration: Paper-and-pencil or on-line, individual, face-to-face
Ages: 4;0-50;11 years
Time: Varies by age/grade and number of subtests administered
Published: 2009
Standardization: standardized on 3,000 students and adults; a portion of sample standardized on both Wechsler IQ tests and WIAT
Scoring: Hand, Computer Software, On-line (Q-Global)
A combination report of the Wechsler IQ and WIAT test results can be generated.

Thomas G. Burns. "Wechsler Individual Achievement Test-III: What is the 'Gold Standard' for Measuring Academic Achievement?" Applied Neuropsychology. Volume 17, Issue 3, 2010.


Document last updated July 2018