An Investigation of the Relationship between Dyslexia Risk, the Simple View of Reading, and the Tests of Dyslexia Probability Index

One hundred eighteen participants identified as having dyslexia were matched on grade, gender, race/ethnicity, SES, and geographic location with examinees from the standardization sample of the Tests of Dyslexia (TOD; Mather et al., in press) in order to determine the relationship between two theoretical operationalizations of dyslexia: the Simple View of Reading (SVR; D X C = R) and the Dyslexia Probability Index (DPI) from the TOD; in addition, the relative power of the SVR and DPI to predict dyslexia status was examined. Additional analyses were conducted on a larger, non-matched sample (n = 1475) to determine the extent to which the ability of SVR Reading Comprehension (SVR R) scores and the DPI scores to predict dyslexia risk are affected by race, gender, and socioeconomic status (SES). Results show that the SVR R and DPI scores were positively and statistically significantly correlated (p < .001). Based on a logistic regression, the DPI predicted the greatest amount of variance in dyslexia status (x²(1) = 69.39, p < .001); the SVR R added a statistically significant portion of variance to the equation (x²(2) = 76.91, p < .001). The SVR R prediction of dyslexia (x²(1) = 119.68, p < .001) was significantly improved by gender (x²(2) = 129.37, p < .001) and SES (x²(5) = 138.65, p < .001). Similarly, the DPI prediction of dyslexia (x²(1) = 125.49, p < .001) was significantly improved by gender (x²(2) = 132.62, p < .001) and SES (x²(5) = 142.24, p < .001). Implications are discussed.