What is the CTOPP-2? The Comprehensive Test of Phonological Processing explained

The CTOPP-2, the Comprehensive Test of Phonological Processing, Second Edition, is an individually administered test that measures the sound-processing skills that support reading. Published by PRO-ED in 2013, it covers ages 4 through 24, takes about 40 minutes, and reports three core composite scores: phonological awareness, phonological memory, and rapid symbolic naming. School psychologists, speech-language pathologists, and reading specialists use it to find out whether a struggling reader's difficulty traces back to how the brain handles the sounds of language. This article explains what the CTOPP-2 measures, walks through its subtests and scores, and covers why phonological processing is worth separating from general intelligence.

"Phonological processing" refers to how a person perceives, stores, and retrieves the sound structure of spoken language. In an influential 1987 review in Psychological Bulletin, Richard Wagner and Joseph Torgesen (two of the CTOPP-2's authors) argued that these sound-based skills play a causal role in learning to read, and the test is organized around that framework. The CTOPP-2 breaks phonological processing into three core areas, each reported as a composite score.

• Phonological awareness: the ability to notice and manipulate the individual sounds ("phonemes") inside spoken words. A child with strong phonological awareness can tell you that "cat" without the /k/ sound is "at."

• Phonological memory: the ability to hold sound-based information in short-term memory for a few seconds, such as repeating back a string of digits or an unfamiliar made-up word.

• Rapid symbolic naming: the ability to quickly retrieve the names of familiar symbols such as letters and digits, which reflects how efficiently phonological information can be pulled from long-term memory.

According to the publisher, confirmatory factor analyses conducted for the second edition supported including the rapid naming tasks within a test of phonological processing. For young children who do not yet know letters and numbers, the test offers a rapid "non-symbolic" naming alternative that uses colors and objects instead.

PRO-ED reports that the CTOPP-2 covers ages 4 years 0 months through 24 years 11 months, with two versions: one for ages 4 to 6 and one for ages 7 to 24. Administration is one-on-one and takes roughly 40 minutes. It is a level B instrument, meaning purchasers need relevant training or credentials, and in practice it is given by school psychologists, speech-language pathologists, educational diagnosticians, and reading specialists, often as one piece of a broader evaluation such as a psychoeducational or neuropsychological assessment. If you want context on how tests like this fit into a fuller battery, see our overview of what neuropsychological testing involves at https://www.riotiq.com/articles/specific-iq-tests-and-formats/what-is-neuropsychological-testing.

The full battery contains 12 subtests. The publisher describes them as follows.

• Elision: removing sounds from spoken words to form new words (say "blend" without the /l/).

• Blending Words: combining separate sounds into a whole word.

• Sound Matching: picking words that share the same first or last sound (ages 4 to 6).

• Phoneme Isolation: identifying individual sounds within words, a subtest added in the second edition (ages 7 to 24).

• Blending Nonwords and Segmenting Nonwords: the same blending and segmenting skills applied to made-up words, which prevents vocabulary knowledge from helping.

• Memory for Digits and Nonword Repetition: repeating number strings and made-up words accurately, the two phonological memory tasks.

• Rapid Digit, Letter, Color, and Object Naming: timed tasks that measure how quickly the examinee can name rows of familiar items.

The original CTOPP appeared in 1999, and the publisher notes it has been used widely in reading research since then. The second edition added easier and harder items so the test now works for 4-year-olds and has better ceilings for older examinees.

The CTOPP-2 uses the same scoring conventions as most standardized cognitive tests. Each subtest yields a "scaled score" with a mean of 10 and a standard deviation of 3, and the composites are reported as index scores with a mean of 100 and a standard deviation of 15, the same metric used for IQ scores. The test also provides percentile ranks, age and grade equivalents, and a newer developmental score for the untimed subtests.

According to the publisher, the norms are based on a sample of 1,900 individuals tested in 2008 and 2009, selected to match U.S. census characteristics. PRO-ED reports average internal consistency reliability above .80 for every subtest except Nonword Repetition (.77), with all composite reliabilities at .85 or higher. Those figures are respectable for subtests and good for composites, though as with any test, a single administration carries measurement error, and important decisions should never rest on one score.

The publisher lists four principal uses for the test: identifying individuals who fall well below their peers in phonological abilities, mapping strengths and weaknesses across phonological skills, documenting progress during intervention, and serving as a research measure.

The link between phonological skills and reading is one of the better replicated findings in educational psychology, though its strength varies by skill and age. A 2012 meta-analysis in Psychological Bulletin by Monica Melby-Lervåg, Solveig-Alma Lyster, and Charles Hulme reviewed the correlational evidence and concluded that "phonemic awareness," the awareness of individual sounds in words, is a substantial correlate of individual differences in reading ability. On the instructional side, the National Reading Panel, convened by the U.S. National Institute of Child Health and Human Development, concluded that teaching phonemic awareness to children significantly improves their reading more than instruction that lacks attention to it, while also cautioning that such training is foundational knowledge rather than a complete reading program.

Phonological processing also sits at the center of how dyslexia is defined. The definition published by G. Reid Lyon, Sally Shaywitz, and Bennett Shaywitz in Annals of Dyslexia, later adopted by the International Dyslexia Association, states that the word-reading and spelling difficulties in dyslexia "typically result from a deficit in the phonological component of language" that is often unexpected in relation to other cognitive abilities. That is why a phonological processing measure like the CTOPP-2 so often appears in dyslexia evaluations alongside reading achievement tests. A modest caveat belongs here: the CTOPP-2 does not diagnose dyslexia on its own. Diagnosis requires a qualified professional integrating multiple sources of evidence, including reading and spelling performance, instructional history, and other cognitive measures.

It is easy to confuse a low CTOPP-2 composite with low intelligence because both use the familiar mean-100 scale. They answer different questions. General intelligence reflects broad reasoning ability across many kinds of content. Phonological processing is a narrower language-related skill, and the dyslexia definition quoted above explicitly describes phonological deficits as often unexpected given a person's other cognitive abilities. In plain terms, a bright child can have weak phonological skills, and that mismatch is exactly what evaluators look for. Vocabulary knowledge, by contrast, is closely tied to general intelligence, a distinction we cover in our article on what vocabulary tests measure at https://www.riotiq.com/articles/specific-iq-tests-and-formats/what-do-vocabulary-tests-measure.

For families navigating a school evaluation, this means a CTOPP-2 report should be read as a profile of specific skills, and any statement about a child's overall ability requires an intelligence test normed for children, a topic we discuss in our guide to IQ tests for kids at https://www.riotiq.com/articles/specific-iq-tests-and-formats/iq-tests-for-kids.

Where does the RIOT IQ test fit? The Reasoning and Intelligence Online Test, developed by RIOT IQ with psychometrician Dr. Russell T. Warne, measures general intelligence in adults 18 and older through 15 subtests across six cognitive indices: verbal reasoning, fluid reasoning, spatial ability, working memory, processing speed, and reaction time. It takes about 52 minutes and reports scores on the same mean-100, standard-deviation-15 scale. It is designed for adults rather than the children who make up most CTOPP-2 examinees, and it measures broad cognitive ability rather than phonological processing, so the two tests complement rather than replace each other. Neither an online IQ score nor a single phonological composite substitutes for an individually administered diagnostic evaluation when a learning disability is in question. Adults curious about their own cognitive profile can take the RIOT IQ test at riotiq.com.

The publisher reports an age range of 4 years 0 months through 24 years 11 months, with a lower version for ages 4 to 6 and an upper version for ages 7 to 24.

No. It measures phonological processing, a specific set of sound-based language skills. Its composites use the same mean-100 scale as IQ scores, but they describe a much narrower ability.

Not by itself. It measures the phonological weaknesses that are central to most definitions of dyslexia, but a diagnosis requires a qualified professional weighing reading achievement, history, and other evidence together.

PRO-ED lists the testing time as about 40 minutes, administered one-on-one.

Subtests are scaled to a mean of 10 with a standard deviation of 3; composites have a mean of 100 with a standard deviation of 15. Scores near 100 on a composite are average for the person's age, and percentile ranks show standing relative to peers.

It is a level B test, typically administered by school psychologists, speech-language pathologists, educational diagnosticians, and similarly trained professionals.

1. Wagner, R. K., Torgesen, J. K., Rashotte, C. A., & Pearson, N. A. (2013). CTOPP-2: Comprehensive Test of Phonological Processing, Second Edition. PRO-ED. proedinc.com

2. Wagner, R. K., & Torgesen, J. K. (1987). The nature of phonological processing and its causal role in the acquisition of reading skills. Psychological Bulletin, 101(2), 192-212. doi.org

3. Melby-Lervåg, M., Lyster, S.-A. H., & Hulme, C. (2012). Phonological skills and their role in learning to read: A meta-analytic review. Psychological Bulletin, 138(2), 322-352. doi.org

4. Lyon, G. R., Shaywitz, S. E., & Shaywitz, B. A. (2003). A definition of dyslexia. Annals of Dyslexia, 53, 1-14. doi.org

5. National Institute of Child Health and Human Development (2000). Report of the National Reading Panel: Teaching children to read. Findings and determinations. nichd.nih.gov

6. Elliott, J. G., & Grigorenko, E. L. (2024). Dyslexia in the twenty-first century: A commentary on the IDA definition of dyslexia. Annals of Dyslexia. pmc.ncbi.nlm.nih.gov

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