What is the TERA-4? The Test of Early Reading Ability explained
The TERA-4 is a 30-minute, individually administered early reading test for ages 4 to 8. Learn its subtests, scores, and how it differs from an IQ test.
Dr. Russell T. WarneChief Scientist
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The TERA-4, short for the Test of Early Reading Ability, Fourth Edition, is an individually administered, "norm-referenced" test of early reading skills for children ages 4 years 0 months through 8 years 11 months. Published by PRO-ED and authored by D. Kim Reid, Wayne P. Hresko, and Donald D. Hammill, it takes about 30 minutes and produces a composite called the General Reading Index from three subtests: Alphabet, Conventions, and Meaning. It measures what a child has already learned about print. It is not an IQ test, and it does not measure reasoning or general intelligence. This article explains what the TERA-4 measures, how it is scored, how it was built, and how it differs from the cognitive tests that often sit beside it in a school evaluation.
What the TERA-4 measures
According to PRO-ED's product description, the TERA-4 is "a direct measure of reading ability in children." The publisher distinguishes this from readiness testing. Rather than asking whether a child is ready to begin reading, the test samples the child's "mastery of early-developing reading skills," the specific knowledge about letters, print, and meaning that children accumulate in preschool and the early primary grades.
The three subtests each target a different layer of that knowledge:
• Alphabet: measures knowledge of the alphabet and its uses, such as recognizing letters and understanding what they do in written language.
• Conventions: measures knowledge of the conventions of print, the rules that govern how written English is organized on a page.
• Meaning: measures comprehension of print. The Texas Education Agency's statewide autism training project describes this subtest as measuring "the construction of meaning from print."
The three subtests combine into the General Reading Index, which the publisher describes as representing overall reading ability. Two forms, A and B, allow an examiner to retest a child without repeating the exact items.
The TERA-4 is broader than instruments that isolate a single skill. A timed word-reading test like the TOWRE-2 focuses on how quickly a child decodes words, and an oral reading test like the GORT-5 measures fluency and comprehension of connected passages in older readers. The TERA-4 sits earlier in development, at the point where a child is still learning what print is and how it works.
How the TERA-4 is administered and scored
The TERA-4 is administered one child at a time by a trained examiner. PRO-ED lists it at qualification Level B, so purchasers generally need training in test administration and interpretation. In practice the examiner is usually a school psychologist, educational diagnostician, reading specialist, or speech-language pathologist. The kit contains an Examiner's Manual, Picture Books for Form A and Form B, packets of 25 Examiner Record Booklets for each form, and a Reader.
Administration takes roughly 30 minutes. Scoring can be done by hand or through the optional TERA-4 Online Scoring and Report System, accessed with activation codes included in each package of record booklets. The publisher says the system converts raw scores into scaled scores, generates the composite index score, percentile ranks, and confidence intervals, compares scores within a child's profile, and produces a narrative report. PRO-ED also notes that the software "ensures accurate application of basals and ceilings," the start and stop rules that keep a young child from being asked items far above or below their level.
According to the Texas Education Agency's summary, the General Reading Index is a "standard score" with a mean of 100 and a standard deviation of 15, the same scale used for IQ scores. The three subtests are reported as "scaled scores" with a mean of 10 and a standard deviation of 3. Percentile ranks and normal curve equivalents are also available. A General Reading Index of 100 means a child performed at the median for their age, and a score of 85 sits one standard deviation below it.
Two cautions apply to any single score. The confidence intervals exist because every test score contains measurement error; a child's true level of early reading skill lies within a range around the obtained score. And the scores describe performance on a particular day. A low General Reading Index is a reason to look more closely, and it is not by itself a diagnosis of anything.
How the TERA-4 was standardized
PRO-ED reports that the TERA-4 was standardized on a representative sample of 1,025 children from 29 states and 271 zip codes, and that the sample included mainstream and minority groups across gender, racial, ethnic, linguistic, and disability categories, with reliability and validity information reported separately for those subgroups.
On reliability, the publisher reports coefficient alpha, test-retest, immediate and delayed alternate-form, and interscorer studies. Average coefficient alphas for the full normative sample range from .88 to .97 for the subtests and reach .98 for the General Reading Index, values consistent with mainstream expectations for a composite used to guide decisions about an individual child.
On validity, PRO-ED describes three lines of evidence. Content validity rested on item selection, controlled vocabulary, review by a panel of language experts, item analysis, and checks of floors, ceilings, and item gradients. Criterion validity was examined by correlating TERA-4 standard scores with other commercial reading measures (the publisher names the ERA, TOSWRF-2, TOSCRF-2, and TOSREC) and by computing sensitivity, specificity, and ROC/AUC statistics, which describe how well a cut score separates children with and without reading problems. Construct validity was studied through the relationship of TERA-4 scores with age, academic achievement, spoken language, and intelligence, the ability of the scores to differentiate groups with known reading problems, and the factor structure of the three subtests.
The publisher also reports that the items were examined with "differential item functioning" techniques, statistical checks for items that behave differently for children of equal ability from different demographic groups. This is the same category of bias analysis that Dr. Warne discusses in the video above, and it is now a standard expectation for any norm-referenced measure used in schools. An independent review of the fourth edition by Alexander M. Rigney appeared in Contemporary School Psychology in 2018.
Where the TERA-4 came from
The Test of Early Reading Ability has been in print for more than four decades. A review of the original TERA in The Reading Teacher in 1985 concluded that it provided a valid and reliable measure of some of the abilities involved in the reading behavior of five- and six-year-olds, while noting that it was not recommended at the lowest and highest extremes of the age range. The second edition, as described in the journal Diagnostique in 1999, covered ages 3 through 9 and already organized its content around the same three ideas that structure the fourth edition: attributing meaning to printed symbols, knowledge of the alphabet and its functions, and understanding the conventions of print.
The third edition, TERA-3, was widely used in American research. According to the National Center for Education Statistics, items from the TERA-3 were taken or adapted for the direct child reading assessment in the Early Childhood Longitudinal Study, Kindergarten Class of 2010-11 (ECLS-K:2011), alongside items from the TEMA-3 for mathematics. That nationally representative cohort continues to feed published research. A 2025 analysis of 17,979 ECLS-K:2011 children in Psychological Science by Lisa Bardach and colleagues used those reading scores alongside mathematics, science, working memory, and cognitive flexibility measures to show that loadings on a general intelligence factor stayed fairly constant from kindergarten through fifth grade while domain-specific factor loadings increased over time.
The fourth edition, with a 2018 copyright according to PRO-ED, covers ages 4-0 through 8-11, added online scoring, and refreshed the norms and psychometric studies described above.
How the TERA-4 differs from an IQ test
The General Reading Index and an IQ score share a scale, and PRO-ED reports that TERA-4 scores were correlated with measures of intelligence during construct validation. The two kinds of tests nonetheless answer different questions.
An "achievement" test like the TERA-4 measures what a child has learned in a specific taught domain. Letters, the direction print runs on a page, and the idea that marks on paper carry meaning are all acquired through exposure and instruction. A child who has had little contact with books will score lower on the TERA-4 regardless of underlying reasoning ability, and the same child may score much higher a year later after good teaching. That sensitivity to instruction is the point of the test.
An intelligence test measures general reasoning ability across content chosen to depend less on any one curriculum. Its scores are more stable over time and predict achievement across many subjects. In a school evaluation, an examiner often administers both kinds of measures, sometimes with a concept test such as the Bracken School Readiness Assessment for younger children, so that reading skill can be interpreted against the child's broader cognitive profile. The 2025 Psychological Science analysis found some evidence that strong domain-specific abilities can partly compensate for lower general intelligence, one more reason a reading score and a reasoning score should not be treated as interchangeable.
The TERA-4 is not designed to diagnose dyslexia, a learning disability, or any other condition on its own. Those determinations belong to qualified clinicians who integrate multiple measures, history, and observation.
For adults who want a defensible estimate of their own reasoning ability, the RIOT IQ test (the Reasoning and Intelligence Online Test) was developed by RIOT IQ with psychometrician Dr. Russell T. Warne for people 18 and older. It contains 15 subtests across six cognitive indices (verbal reasoning, fluid reasoning, spatial ability, working memory, processing speed, and reaction time), takes about 52 minutes, and reports scores on the same mean-100, standard-deviation-15 scale. It does not replace an individually administered diagnostic evaluation. You can learn more or take the test at RIOT IQ.
Frequently asked questions
What ages does the TERA-4 cover?
PRO-ED states that the TERA-4 is designed for children ages 4 years 0 months through 8 years 11 months.
How long does the TERA-4 take?
The publisher and its distributors list a testing time of 30 minutes. The test is administered individually, one child with one examiner.
What scores does the TERA-4 produce?
The General Reading Index is a standard score with a mean of 100 and a standard deviation of 15. The Alphabet, Conventions, and Meaning subtests yield scaled scores with a mean of 10 and a standard deviation of 3, and percentile ranks and normal curve equivalents are also reported.
Is the TERA-4 an IQ test?
No. It is a norm-referenced measure of early reading skills that children learn through exposure and instruction. IQ tests measure general reasoning ability across content that depends less on any one curriculum.
Can the TERA-4 diagnose dyslexia?
No. It can document that a child's early reading skills are well below age expectations, which may prompt further evaluation. Diagnosis requires a qualified clinician integrating multiple sources of evidence.
References
1. PRO-ED. (n.d.). TERA-4: Test of Early Reading Ability, Fourth Edition, Complete Kit. proedinc.com
2. Wheeler, N. J. (1999). Test of Early Reading Ability-2. Diagnostique, 24(1-4), 229-240. eric.ed.gov
3. Texas Statewide Leadership for Autism Training, Texas Education Agency. (n.d.). Test of Early Reading Ability, Fourth Edition. txautism.net
4. Rigney, A. M. (2018). Test review: D. K. Reid, W. P. Hresko, and D. D. Hammill, Test of Early Reading Ability, Fourth Edition. Austin, TX: Pro-Ed, 2018. Contemporary School Psychology, 24(1), 102-105. doi.org
5. Tourangeau, K., Nord, C., Le, T., Sorongon, A. G., Hagedorn, M. C., Daly, P., & Najarian, M. (2015). Early Childhood Longitudinal Study, Kindergarten Class of 2010-11 (ECLS-K:2011): User's manual for the ECLS-K:2011 kindergarten data file and electronic codebook, public version (NCES 2015-074). National Center for Education Statistics. nces.ed.gov
6. Bardach, L., Kalinowski, R., & Bailey, D. H. (2025). Differentiation in cognitive abilities beyond g: The emergence of domain-specific variance in childhood. Psychological Science, 36(3), 168-183. pmc.ncbi.nlm.nih.gov
7. Wisxon, S. E. (1985). Test review: The Test of Early Reading Ability (TERA). The Reading Teacher, 38(6), 544-547. eric.ed.gov
Hero photo: A pile of wooden letter tiles. Photo by WOKANDAPIX, via Wikimedia Commons, CC0 (cropped).
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