DYMOND™ Validity and Reliability

Validity

The DYMOND Examiners Manual provides detailed evidence of the valid interpretation and uses of the DYMOND. An overview of the evidence of validity, organized according to the purposes of the DYMOND, is provided below.

Purpose: The DYMOND was design to accurately identify language learning disorder (e.g., DLD) and decoding learning disorder (e.g., dyslexia)

The DYMOND’s subtests measure both current performance and learning potential. Sensitivity and specificity analyses demonstrate the test’s high accuracy in identifying language and decoding disorders, with excellent performance in distinguishing typically developing children from those with language disorders or dyslexia. This high sensitivity and specificity is consistent across diverse demographic backgrounds. Additional evidence from comparisons of means and standard deviations between groups (tables and box plot graphs are available in the Examiner’s Manual), reveals distinct differences in score distributions. Developmental trends in dimensions measuring current performance further bolster the test’s validity, reflecting expected patterns across ages, while dimensions measuring learning potential appropriately show limited developmental trends.

Sensitivity and Specificity: Key Indicators of Diagnostic Validity

Sensitivity and specificity are critical metrics for determining the DYMOND’s accuracy in identifying language and decoding learning disorders.

• Sensitivity ensures that children with a disorder are accurately diagnosed, reducing false negatives, and thereby preventing delays in necessary interventions.
• Specificity ensures that children without a disorder are not mistakenly identified as needing intervention, minimizing unnecessary services and stigma.

The DYMOND has excellent sensitivity (e.g., 95%) and excellent specificity (e.g., 91%) as reported in the tables below. Both metrics provide strong evidence of the DYMOND’s diagnostic accuracy, balancing the identification of true positives and minimizing false positives. This balance ensures that appropriate decisions are made regarding interventions and services. Additionally, high sensitivity and specificity are essential for equitable decision-making, especially when evaluating children from diverse cultural and linguistic backgrounds. The DYMOND’s ability to maintain diagnostic accuracy across various populations provides further evidence of its validity for use in diverse educational contexts.

Purpose: Identifying Strengths, Weaknesses, and Instructional Targets

The intended consequences of the DYMOND include improved educational outcomes through timely, targeted interventions that enhance language and literacy skills. The DYMOND results help identify strengths and weaknesses which inform the development of targeted instructional plans. The DYMOND also ensures fair and equitable access to services across culturally and linguistically diverse populations, ensuring children from all backgrounds are fairly evaluated. Early identification through the DYMOND and early intervention should lead to sustained academic and developmental progress, helping children build strong language, reading, and writing skills over time.

• Identifying Strengths and Weaknesses: By comparing the means and standard deviations of children with learning disorders to those without, the DYMOND helps pinpoint specific areas of strengths and weaknesses across subtests. The large effect sizes indicate meaningful differences between these groups, reinforcing that the test is capable of differentiating performance levels.
• Informing Instruction: The ability to identify these strengths and weaknesses allows examiners to set instructional targets. Children with lower scores in specific subtests can benefit from targeted, individualized support to address those areas of difficulty. The data from the DYMOND also help determine the intensity of support a child may need compared to their peers, guiding decisions about whether more intensive interventions are necessary.

Reliability refers to how consistently a test can measure something across different conditions and situations. If a test lacks reliability, then the examiner will have limited confidence in the results of that test. The reliability of the DYMOND was evaluated through both simulated test-retest reliability and inter-rater reliability analyses, with high intraclass correlation coefficients (ICCs) observed in both. These high ICC values indicate strong consistency in test results across administrations and across different raters, demonstrating robust reliability, giving examiners confidence in its consistency and dependability when assessing language and decoding skills.

Simulated Test-Retest ICCs

Inter-rater Reliability ICCs