Ferrer, E., Shatwitz, B.A., Holahan, J.M., Marchione, K.E., Michaels, R., and Shaywitz, S.E. (2015) Achievement Gap in Reading Is Present as Early as First Grade and Persists through Adolescence, Journal of Pediatrics, November 2015,167 (5):1121-1125.
The subjects were the 414 participants comprising the Connecticut Longitudinal Study, a sample survey cohort, assessed yearly from 1st to 12th grade on measures of reading and IQ. Statistical analysis employed longitudinal models based on growth curves and multiple groups. Results from the study indicated that as early as first grade, compared with typical readers, dyslexic readers had lower reading scores and verbal IQ, and their trajectories over time never converge with those of typical readers. Researchers concluded that the achievement gap between typical and dyslexic readers is evident as early as first grade, and this gap persists into adolescence. These findings provide strong evidence and impetus for early identification of and intervention for young children at risk for dyslexia. Implementing effective reading programs as early as kindergarten or even preschool offers the potential to close the achievement gap.