Cognitive processes as predictors of reading success

One hundred and five elementary and middle school students from a rural East Tennessee school district were evaluated using a new test of dyslexia, the Test of Dyslexia and Dysgraphia (TODD; McCallum & Bell, 1999). The TODD includes cognitive measures presumed to underlie reading. Also, reading achievement was assessed using the TODD, and for 73 of the students, by an end-of-year group administered test, the Terra Nova.

When cognitive variables were entered into Multiple Regression Analyses using reading achievement scores as criteria, Phonological Awareness was the strongest predictor of all criterion measures after extracting the variance accounted for by age. That is, phonological awareness predicted Letter-Word Calling, Decoding, Reading Comprehension, and Terra Nova Spelling and Reading Composite scores, of variance accounting for from 76% to 21% for the criterion variables. Phonological awareness was the only significant predictor of Decoding and Terra Nova Reading Composite. However, when age was partialled out, the Reading Composite was significantly predicted by phonological awareness followed by visual processing which contributes an additional 4% of the variance, while Decoding was significantly predicted by phonological awareness followed by auditory memory which contributes an additional 1% of the variance. When age is not partialled out, phonological awareness accounted for 76% of the variance in Letter-Word Calling; rapid automatic naming accounted for an additional 6% above that already accounted for by phonological awareness; visual processing accounted for an additional 2%, as did auditory processing; finally, auditory memory accounted for an additional 1%. When age is controlled for, phonological awareness accounted for 60% of the variance in Letter-Word Calling; Auditory processing accounted for an additional 1% of the variance; and visual memory accounted for less than 1% additional variance. When age is uncontrolled, phonological awareness accounts for 54% of the variance for Reading Comprehension and rapid automatic naming, visual processing and auditory memory account for 7%, 4%, 1% and 1% additional variance, respectively. When controlling for age, phonological awareness accounts for 19% of the variance for Reading Comprehension, and auditory processing and visual memory each predict an additional 1% of the variance, respectively. After phonological awareness, the next significant predictor of Terra Nova Spelling was auditory processing accounting for an additional 3% of the variance when age was not partialled out. When controlling for age, phonological awareness, auditory processing and visual memory predicted Spelling accounting for 20%, 6%, and 3% of additional variance, respectively.

These results are commensurate with current research emphasizing the predominance of phonological awareness and support the relative importance of rapid automatic naming, auditory memory and processing, and visual memory and processing in explaining the acquisition of beginning reading. Teachers of reading will find these results useful in understanding and designing curricula to develop the basic building blocks of reading. Assuming data continue to support the development of the TODD, school psychologists will benefit from having one test available to diagnose dyslexia, rather than having to choose various subtests taken from a variety of instruments.