The Tests of Dyslexia (TOD®) is a comprehensive assessment battery designed to identify and diagnose dyslexia in individuals from kindergarten through adulthood (ages 5 to 89). Released around 2024, it is the first co-normed assessment to consolidate screening, diagnosis, and intervention planning into a single tool, eliminating the need to combine multiple disparate tests.
Core Components
The TOD consists of three distinct batteries that can be used independently or as a sequence:
- TOD-S (TOD-Screener): A brief 10–15 minute assessment for individuals or groups. It provides a Dyslexia Risk Index (DRI) to determine if more in-depth testing is necessary
- TOD-E (TOD-Early): Tailored for young children (ages 5:0 to 9:3) who are typically pre-readers or emerging readers. It yields an Early Dyslexia Diagnostic Index (EDDI)
- TOD-C (TOD-Comprehensive): Designed for students and adults (ages 6:0 to 89:11) who can read connected text. It provides a Dyslexia Diagnostic Index (DDI)
Assessment Areas
The tests measure skills across three primary domains:
- Reading and Spelling: Sight word acquisition, phonics knowledge, decoding efficiency, reading fluency, and reading comprehension efficiency
- Linguistic Processing: Phonological awareness (rhyming, blending, segmenting), orthographic processing, rapid automatized naming (RAN), and auditory working memory
- Vocabulary and Reasoning: Measures verbal ability and non-verbal reasoning to determine if reading difficulties are “unexpected” relative to other cognitive strengths
Key Features
- Linked Interventions: Includes the Dyslexia Interventions and Recommendations Companion Guide, which maps assessment results directly to evidence-based instruction strategies
- Co-Normed Rating Scales: Gathers qualitative data from parents, teachers, and the individual regarding family history, speech delays, and attitude toward reading
- Flexible Administration: Can be administered in-person (paper or digital) or remotely
- Progress Monitoring: Uses growth scores sensitive to small changes to track a student’s response to intervention over time.
Who would use the TOD?
The Tests of Dyslexia (TOD®) is a “Level B” qualification assessment, meaning it is used by a broad range of educators and clinicians who have professional training in standardized testing and a relevant bachelor’s or master’s degree.
- Benefit: Allows practitioners and educators to accurately assess and diagnose dyslexia and specific learning disability in reading, provides risk and probability indexes, and includes intervention recommendations based on assessment results
- Ages: 5 to 89 years
- Testing Time: TOD-S: 10–15 minutes; TOD-E: additional 20–25 minutes after TOD-S; TOD-C: additional 30–40 minutes after TOD-S to obtain DDI, LPI, and RSI with additional tests at 5-10 minutes each
- Administration: TOD-S can be administered to individuals or groups; TOD-C and TOD-E are individually administered; available in digital or paper formats
- Qualification Code: B – Click HERE for more details
- Norms: 2,518 individuals aged 5 to 89 in standardization and validation studies. Standardization sample closely matches U.S. Census data for gender, race/ethnicity, parents’ educational level, and geographic area
- Audio File: Available for download HERE
- Scores: Standard and composite scores, percentile ranks, confidence intervals, age- and grade-equivalents; growth scores for monitoring progress. TOD Rating Scales provide T-scores, percentiles, confidence intervals, and level of risk.
