(TOD™) Tests of Dyslexia

The Tests of Dyslexia (TOD) is a comprehensive battery of tests and resources designed to help identify and plan interventions for individuals of all ages with dyslexia. It is authored by Nancy Mather, PhD, R. Steve McCallum, PhD, Sherry Mee Bell, PhD, and Barbara J. Wendling, MA.

The TOD identifies the risk and probability of dyslexia or specific learning disability in reading in individuals aged 5 to 89. The TOD also provides instruction and intervention recommendations based on assessment results.

The TOD has three batteries: the TOD-Screener, three tests that can be administered to groups or to individuals, available in a paper or digital format; the TOD-Early, designed for the early identification of students in Grades K–2 (5 years, 0 months–9 years, 3 months); and the TOD-Comprehensive, designed for examinees from Grade 1 to adulthood (6 years, 0 months–89 years, 11 months).

The TOD includes: 1) indexes designed to indicate the risk and probability of dyslexia; 2) composites and tests that measure reading skills (untimed and timed), spelling, specific linguistic risk factors (phonological awareness, orthographic processing, rapid automatized naming, and working memory), and vocabulary and reasoning abilities; 3) Self, Parent, and Teacher Rating Scales designed to indicate risk of dyslexia as well as capture qualitative indicators of dyslexia, such as a family history of reading problems and early difficulties with speech and language; and 4) the Dyslexia Interventions and Recommendations guide to help examiners develop IEPs and targeted intervention plans to address specific skill weaknesses.

First, the TOD covers a wide age range and includes the major components that are needed for a comprehensive dyslexia assessment. There is no need to cobble together results from different tests with different norm groups. Second, the TOD includes the reading and linguistic abilities that are most relevant to the diagnosis of dyslexia. The TOD includes measures of word recognition (untimed and timed), phonics knowledge, reading fluency, and comprehension efficiency (the ability to comprehend text under time pressure). The TOD also includes linguistic risk factors (e.g., phonological awareness, rapid automatized naming) that can help determine the factors that are affecting reading development. Third, the TOD includes measures of vocabulary and reasoning to help determine if the reading problem is specific and/or unexpected in relation to abilities that do not require reading. Fourth, the TOD includes rating scales to help standardize the process of collecting information from parents, teachers, or individuals being assessed. Fifth, the TOD includes a guide to interventions to help develop an instructional plan.

Professional standards in testing are presented in the Standards for Educational and Psychological Testing published by the American Educational Research Association (AERA), American Psychological Association (APA), and the National Council on Measurement in Education (NCME). Examiners should use only those tests for which they have the appropriate training and expertise. All the TOD components can be purchased by educators, psychologists, and related professionals who serve students who may have dyslexia. These are Level B tests, so examiners must have a bachelor’s degree in psychology or a related discipline (e.g., school counselors, speech and language pathologists, social workers, special education teachers, medical professionals) and training and instruction in administration and interpretation of standardized tests.

The components of the TOD can be used by a variety of clinicians and educators. For example, a classroom teacher may administer the TOD-Screener and complete the Teacher Rating Scale. Reading specialists, educational diagnosticians, psychologists, and speech–language pathologists are best suited to administer the TOD-Early or the TOD-Comprehensive due to their advanced coursework and experience with standardized tests. Teachers who are trained to administer the test and are supervised by professionals who have advanced training with standardized assessments may also administer the TOD-E or TOD-C. Interpretating test results requires a higher level of skill. For that reason, while a broader range of individuals can administer the test, interpretating results requires a knowledge of dyslexia and formal training in test administration, scoring, and interpretation.

WPS ProLearn™ offers a variety of webinars and TOD-specific training videos, as well as an Independent Study, all with the opportunity to purchase CEs after completion. Professional development and learning opportunities are continually updated to reflect the needs of our customers. Additionally, your WPS Assessment Consultant can arrange both product demonstration and training.

The TOD-S can be administered digitally on OES and scored automatically or can be administered on paper. The TOD-C and TOD-E can only be administered on paper (although pdf easels are available for remote/digital administration, responses are recorded/scored on a paper record form). When administered on paper, the TOD-S, TOD-C, and TOD-E can be hand-scored or scored on OES for free. This free online scoring and reporting provides a convenient alternative to hand-scoring as well as an interpretive score report and access to a customizable intervention report.

The rating scales included in the TOD-C, TOD-E, and TOD Combination kits are only available on our Online Evaluation System™ (OES) at platform.wpspublish.com. Once you use the activation code on the OES, you can print out any of the Parent, Teacher, or Self-Rating Forms at no extra cost and as many times as you want if you prefer to administer any forms on paper. However, you still have to score the response forms online, which gives you access to beneficial reporting options.

You may purchase any of the TOD kits (Combination, Screener, Early, or Comprehensive), all of which include forms, manual, and intervention planner, or you may purchase individual items. Reach out to customerservice@wpspublish.com or call us at 844.378.4918 with any purchasing questions.

The answer to this question is complicated and requires some context. Reliability and validity evidence occurs over time and from multiple studies and methodologies. It cannot be defined by single scores. Expert recommendations for interpreting reliability and validity estimates are produced by statistical equations. In general, the reliabilities of the tests and composites are almost all >.80 and thus support the stability of the TOD across tests and over time. Several studies provide validity evidence for the TOD. Confirmatory factor analyses support the factorial structure of the Dyslexia Risk and Diagnostic Index scores, as well as the component Reading and Spelling and Linguistic Processing Index scores. Additionally, concurrent validity analyses demonstrate that each TOD test correlates in expected ways with other tests of similar constructs. Most importantly, comparisons between typically developing individuals and those with a diagnosed reading disability show that the latter group performs more poorly on the TOD measures. This disparity in performance represents a clinically meaningful difference. Furthermore, at a cutoff score of 80, the TOD-S Dyslexia Risk Index discriminates individuals with a reading disability from typically developing individuals with sensitivity of ≥.80 and specificity of ≥.99; the TOD-C Dyslexia Diagnostic Index does so with sensitivity of ≥.78 and specificity of ≥.97; and the TOD-E Early Dyslexia Diagnostic Index does so with sensitivity of ≥.80 and specificity of ≥.99. Sensitivity increases as the cutoff score increases. These results support the utility of the TOD in both clinical or school settings to identify individuals with dyslexia. A full explanation of reliability and validity evidence for the TOD can be found in chapter 5 of the manual.

2,518 individuals aged 5 to 89 participated in the standardization and validation studies. The TOD normative samples are TOD-C child (n = 1,401); TOD-C adult (n = 342); and TOD-E (n = 347). The TOD-S was taken by individuals in each of the three samples and serves as the basis for the TOD-S standardization. Each sample closely matches U.S. Census data based on gender, race/ethnicity, parents’ educational level, and geographic region. The remaining individuals made up the clinical validation samples and had a reading disability and/or other clinical diagnosis.

2024

The TOD manual, norms, administration booklet, intervention guide, and TOD-E and TOD-C easels are available in pdf digital format. Examiners can use the TOD-E and TOD-C pdf easels for remote administration, but paper materials, record forms, and response booklets are still required. Free online scoring for TOD-S, TOD-C, and TOD-E is available on the WPS Online Evaluation System (platform.wpspublish.com). The TOD-Screener is available as a paper kit or an online kit with full online administration capabilities, without the use of paper materials. TOD Rating Scales are administered and scored online only, but a paper version can be downloaded for use with parents, teachers, or individuals who do not have online access at no extra cost. Examiners will need to enter the responses into the Online Evaluation System to obtain the score.