In several recent papers focusing on the causes and correlates of specific reading disability (dyslexia), we and our colleagues expressed serious concerns over current psychometric/exclusionary approaches to classifying children as disabled readers (Scanlon & Vellutino, 1996; 1997; Vellutino, Fletcher, Snowling, & Scanlon, in press; Vellutino & Scanlon, 2001; 2002; Vellutino, Scanlon, Sipay, Small, Pratt, Chen, & Denckla, 1996; Vellutino, Scanlon, & Lyon, 2000; Vellutino, Scanlon, & Tanzman, 1998). Clinical assessment to document that an impaired reader is afflicted by specific reading disability typically entails psychometric assessment having the IQ-achievement discrepancy as the central defining criterion, along with exclusionary criteria such as uncorrected sensory deficits, emotional disorder, socioeconomic disadvantage, general learning problems and like factors. Such approaches can be criticized on several grounds.
First, they do not adequately distinguish between reading difficulties caused primarily by limitations in early literacy experiences and early literacy instruction on the one hand, and reading difficulties caused primarily by biologically-based limitations in reading-related cognitive abilities on the other, because they do not control for the child's pre-school and educational history (Clay, 1987). Second, they often classify children as disabled readers on the basis of assessment instruments that have little or no diagnostic validity (e.g. figure copying tests), in terms of their relationship to reading ability (Vellutino et al., 1977). Third, they give undue weight to the IQ-achievement discrepancy in classifying children as disabled readers (Fletcher et al, 1994; Gresham, 2002; Siegel, 1988, 1989; Stanovich & Siegel, 1994; Vellutino et al., 1998; 2000). Fourth, they tend to inflate the number of children classified as disabled readers, current estimates ranging from 10% to 20% of the population of school-age children (Harris & Sipay, 1990; Lyon, Fletcher, & Barnes, 2002; Shaywitz et al., 1992). Fifth, they create low expectations for children so classified, as do most diagnostic labels. And, sixth, they provide no direction for remedial or classroom instruction (Vellutino et al., 1998, 2000). These concerns motivated us to embark on a program of intervention research to begin to develop the means for distinguishing between cognitive versus experiential/instructional deficits as primary causes of early and protracted reading difficulties, and for identifying children at risk for reading difficulties before exposure to formal reading instruction.
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Abstract | First-Grade Study
