How to Get the Most Out of the CASL-2, Clinicians’ Favorite Speech–Language Assessment

Elizabeth Carrow-Woolfolk, PhD, knows how popular her CASL-2 language assessment is among clinicians. But she believes the strongest part of the assessment may very well be the least utilized—comparing index scores that can help pinpoint the particular language area where a student is struggling.

The test’s index scores are based on factor analysis, a statistical method that identifies how a set of items or tests relate. These scores allow clinicians to make better judgments based on statistical data when they analyze a child’s language skills and identify specific problem areas. 

For example, clinicians can compare expressive and receptive language because the data show that these involve different sets of skills. They can also compare the semantic, syntactic, and supralinguistic structures of language.

‘Actual evidence’ identifies different skills

“I think it’s kind of revolutionary, actually,” Woolfolk said in an interview. “We’ve always been able to say, yes, expression and reception are different. We suspected it; we could tell by the individual behavior that it was, but we never had actual evidence that allows the measurement of difference and whether it is significant or not.” 

Woolfolk, 90, reflected that for most of her life the various speech-language tests on the market simply identified a “language problem” if a child scored poorly in any area of comprehension or vocabulary.

Researchers may have suspected that these processes were different but didn’t have the actual evidence now shown in the CASL-2 factor analysis. Even the famous linguist Noam Chomsky has said that learning grammar is different from learning words, though at the time there were no data to back up the claim.

How many index scores are there? 

The CASL-2 distinguishes between skills required to process language (expressive vs. receptive ability), as well as categories of language structures (vocabulary vs. grammar). The best-selling assessment provides six Index Scores, which can be compared to each other to determine with a degree of certainty whether any significant differences exist among them: 

• General Language Ability
• Expressive Language
• Receptive Language
• Lexical/Semantic
• Syntactic
• Supralinguistic

The factor analysis was performed during the development of the revised second edition of the CASL, published in 2017 by WPS. The original CASL, published in 1999, as well as the second edition, was based on Woolfolk’s Integrative Language Theory, which separates language into the components of structure and processing. The assessment then further divides these components into item types that prompt language behaviors reflecting competence and use.

Across all age groups, the results of the factor analysis support Woolfolk’s theory of language being comprised of separate skill areas as compared to a single factor of language.

“The test follows a theory that provides an understanding of language that helps you identify what parts of the language might be defective, and surprisingly enough, it works,” Woolfolk said. “It helps the tester to identify what the individual understands, but has difficulty expressing; the identification can be made with a significant degree of certainty.  When you separate it out, you can evaluate what the problem is.”

Woolfolk added, “Learning vocabulary, learning grammar, and learning non-literal language are different processes and may be controlled differently in the brain. We don’t know yet what part of the brain is involved or if different parts are contributing, but we do know now that the processes described earlier are different.”

‘How far we can go’

Woolfolk, a recognized expert in language development and disorders, has authored and developed numerous assessments, including the OWLS-II and the OPUS.

Developing tests started early in her career while working in a San Antonio clinic. A three-year-old boy who was completely echolalic arrived at the clinic. Most specialists would have labeled him intellectually disabled, but Dr. Woolfolk wanted to try to teach him, and she did.

After working with him for one and a half years, “I never knew what he didn’t know and what he knew,” Woolfolk said. 

At first, she experimented using photos of the boy and his mother. Woolfolk and the boy slowly went over details of the photos as well as pictures of other objects. She determined he knew a bit more than he seemed to.

She thought, I’m going to develop a little test for him to see “how far we can go.”

The first test authored

The test was used in the clinic for a while before officials at an educational state association in San Antonio heard about it and asked if they could use it. Woolfolk said they were welcome to use the test. It didn’t even occur to her to have it published. But the state education officials liked it and used it with bilingual children. 

Eventually, Woolfolk was approached by a publisher in 1960, and she agreed to publish the test.

“That was the beginning of the TACL,” Woolfolk said.

Those close to Woolfolk say she has a strong drive to help people in need and to do the very best she can for children with language difficulties, which is why she wants clinicians to take advantage of the factor analysis–based index scores of the CASL-2. 

“I think it will help them very much in making decisions about children’s problems,” Woolfolk said.

Asked where her passion for developing tests comes from, Woolfolk cited her curiosity about knowing what causes problems, perseverance in researching the literature, and caring for the children who need help. She remembers her father sitting in his office, methodically organizing his stamp and coin collections, and wonders if she received those skills from him. 

“I guess part of that patience and the desire to establish order, to clarify and categorize, and to learn, is just something I inherited,” Woolfolk said. “I tend to be a person who likes to get to the bottom of things and share what I have found with others.”

Woolfolk added, “I have a great love for language and learning, and that has been what drives me.”

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