What is the OWLS-II? The Oral and Written Language Scales explained

The OWLS-II (Oral and Written Language Scales, Second Edition) is an individually administered language assessment authored by psychologist Elizabeth Carrow-Woolfolk and published by WPS in 2011. It measures four language processes on four separate scales: Listening Comprehension, Oral Expression, Reading Comprehension, and Written Expression. The two oral scales cover ages 3 through 21, the two written scales cover ages 5 through 21, and every scale reports "standard scores" (scores placed on a common scale for comparison) with a mean of 100 and a standard deviation of 15. This article explains what each scale measures, how the test is scored, the theory behind it, who uses it, and how language scores relate to verbal intelligence.

According to WPS, the OWLS-II evaluates four language processes on four separate scales, and each scale samples the same four "linguistic structures": lexical/semantic (word meanings), syntactic (sentence grammar), pragmatic (language use in context), and supralinguistic (higher-order meaning such as inference and figurative language). Because the same structures are examined across listening, speaking, reading, and writing, an examiner can see whether a problem lives in one channel of language or cuts across all of them.

• Listening Comprehension (LC): measures receptive oral language. The examiner reads a word or phrase aloud and the examinee points to the one of four pictures that best depicts its meaning. No reading is required.

• Oral Expression (OE): measures expressive oral language. The examinee answers questions, completes sentences, and generates sentences in response to pictures and spoken prompts. The publisher notes that acceptable alternative responses are provided for students who speak African-American English.

• Reading Comprehension (RC): new to the second edition, this scale measures the receptive side of written language. Items typically ask the student to read a prompt and choose one of four response options, and the scale adds text structure to the four linguistic structures measured elsewhere.

• Written Expression (WE): measures expressive written language with classroom-like tasks, from copying words and writing dictated sentences to completing a story. Beyond the core structures, it also scores conventions such as spelling, punctuation, capitalization, and text organization.

The scales can be used alone, in oral or written pairs, or as a full battery. WPS describes the combination as "more than the sum of its parts" because the co-normed profile pinpoints strengths and weaknesses across modalities rather than in isolation.

The Listening Comprehension and Oral Expression scales are normed for ages 3 through 21, while Reading Comprehension and Written Expression begin at age 5. Administration is individual, with the examinee speaking, pointing, or writing depending on the scale. WPS lists 10 to 20 minutes for Listening Comprehension, 10 to 30 minutes for Oral Expression, 10 to 30 minutes for Reading Comprehension, and 15 to 30 minutes for Written Expression, so a full four-scale battery generally fits within about an hour and a half. Basal and ceiling rules keep the child working on items near their ability level.

All four scales were normed on a single national sample of 2,123 individuals from 31 states, stratified to match the U.S. population on ethnicity, gender, region, and parental education. Norms are age-stratified in fine steps for young children (every 3 months from ages 3 to 7) and wider intervals thereafter, which matters because language grows quickly in the preschool years.

Each scale yields age-based and grade-based standard scores with a mean of 100 and a standard deviation of 15, along with percentile ranks, test-age and grade equivalents, and descriptive categories running from Exceptional down to Possibly Disordered. The WPS scoring documentation notes that scores within one standard deviation of the mean (85 to 115) are considered within average limits. Scale scores combine into five composites: Oral Language, Written Language, Receptive Language, Expressive Language, and Overall Language. A parallel Form B, usable from age 5, allows retesting after a brief interval for progress monitoring. Purchase requires a Level C qualification, meaning an advanced degree and training in psychological assessment or a related field.

The OWLS-II is unusual among language batteries in how explicitly it is built on a single theoretical model. Carrow-Woolfolk designed the instrument around what the publisher calls "Integrated Language Theory," a framework that treats listening, speaking, reading, and writing as four expressions of one underlying language system, each analyzable through the same set of linguistic structures. WPS ships a dedicated handbook with the kit, Foundations of Language Assessment, that lays out this theory and its implications for interpretation, and the publisher reports that factor analysis of the standardization data supports the validity of the theory's underlying constructs.

The practical payoff is coherence. A child's inference skills, for example, are probed in the listening items, the reading items, and the expressive tasks, so an examiner can ask whether a comprehension problem reflects weak supralinguistic processing in general or a difficulty specific to print. That kind of question is hard to answer when oral and written measures come from different tests normed on different samples.

Reliability evidence is solid for a test of this type. An outcome-measure review maintained by researchers at the University of New South Wales reports internal consistency coefficients of .95 or higher in a speech-and-language-impaired sample, interrater reliability in the mid .90s for the open-ended scales, and alternate-forms correlations with a median of .78. The same review notes the OWLS-II scales differentiated typically developing children from clinical groups in the validity studies.

Speech-language pathologists are the core users, with school psychologists, special educators, and clinical researchers close behind. WPS positions the test for identifying students with language disorders and language-based learning disabilities under IDEA eligibility requirements, designing intervention targets, monitoring progress with the parallel form, and gathering longitudinal research data. The co-normed design is the signature feature in schools: because the oral and written scales share one normative sample, a significant gap between a student's Oral Language and Written Language composites is interpretable evidence rather than an artifact of comparing two different tests.

The main alternative in many districts is the Clinical Evaluation of Language Fundamentals, currently the CELF-5, published by Pearson in 2013 for ages 5 through 21. The two instruments reflect different philosophies. Pearson describes the CELF-5 as a flexible battery of 16 tests measuring semantics, morphology, syntax, and pragmatics, from which the clinician assembles a Core Language Score and diagnostic index scores. The OWLS-II instead offers four broad scales built on one theory, with every scale sampling the same linguistic structures. In practice, the OWLS-II starts earlier (age 3 versus 5), folds reading and writing into the same co-normed system, and produces a leaner set of scores, while the CELF approach gives finer-grained subtest information about specific oral language skills. Many evaluators use them in complementary roles rather than treating one as a replacement for the other.

Language ability and intelligence are related but distinct. Tests like the OWLS-II measure developed language skill, which overlaps heavily with the verbal reasoning component of intelligence tests. The overlap is strongest for vocabulary. Research on the Peabody Picture Vocabulary Test, a receptive vocabulary measure similar in format to the OWLS-II Listening Comprehension scale, illustrates the point: Castellino and colleagues reported in the Journal of Neuro-Oncology that PPVT-III scores correlated .89 with Wechsler verbal IQ in their sample, while earlier studies they cite found more moderate values around .68 to .74. This is why vocabulary tests behave like reasonable proxies for verbal ability without being IQ tests themselves.

The distinction matters for interpretation. A low OWLS-II score flags a language problem; it does not by itself say anything about nonverbal reasoning, spatial ability, or processing speed. That is exactly why evaluators pair language scales with cognitive measures when deciding whether a student's difficulty is a specific language disorder or part of a broader cognitive profile.

For adults who want a reading on the cognitive side of that equation, the RIOT IQ test (Reasoning and Intelligence Online Test), developed by RIOT IQ with psychometrician Dr. Russell T. Warne, measures 15 subtests across six cognitive indices: verbal reasoning, fluid reasoning, spatial ability, working memory, processing speed, and reaction time. It takes about 52 minutes, is designed for adults 18 and older, and reports scores on the same mean-100, standard-deviation-15 scale the OWLS-II uses, which makes results easy to interpret side by side. Like any online measure, it does not replace an individually administered diagnostic evaluation, but it offers a normed, research-grade picture of general cognitive ability. You can take it at riotiq.com.

The Listening Comprehension and Oral Expression scales cover ages 3 through 21. The Reading Comprehension and Written Expression scales cover ages 5 through 21.

Each scale takes roughly 10 to 30 minutes according to WPS, so a single scale is quick while the full four-scale battery typically runs about an hour to an hour and a half.

Each scale gives age-based and grade-based standard scores (mean 100, standard deviation 15), percentile ranks, test-age and grade equivalents, and descriptive categories, plus five composites including Overall Language.

No. It measures oral and written language skills. Language scores correlate substantially with verbal intelligence, but the OWLS-II is not designed to estimate general cognitive ability.

WPS sells it at qualification Level C, which generally means professionals with advanced training in assessment, such as speech-language pathologists and school or clinical psychologists.

The forms are parallel versions. WPS notes that Form A begins at age 3 for the oral scales and age 5 for the written scales, while Form B begins at age 5 for all scales and supports retesting after a brief interval.

1. Western Psychological Services. (2011). Oral and Written Language Scales, Second Edition (OWLS-II) [Product description]. wpspublish.com

2. Western Psychological Services. (2011). OWLS-II scoring summary and interpretive sample report. schoolhealth.com

3. Texas Statewide Leadership for Autism Training. (n.d.). Oral and Written Language Scales, Second Edition. txautism.net

4. Pearson. (2013). Clinical Evaluation of Language Fundamentals, Fifth Edition (CELF-5) [Product description]. pearsonassessments.com

5. Castellino, S. M., Tooze, J. A., Flowers, L., & Parsons, S. K. (2011). The Peabody Picture Vocabulary Test as a pre-screening tool for global cognitive functioning in childhood brain tumor survivors. Journal of Neuro-Oncology. pmc.ncbi.nlm.nih.gov

6. University of New South Wales, School of Psychology. (n.d.). Outcome measure: Oral and Written Language Scales, Second Edition (OWLS-II). www2.psy.unsw.edu.au

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