Abstract. This study was conducted to determine whether the cognitive performance of reading disabled and poor readers can be separated under dynamic assessment procedures, and whether measures related to dynamic assessment add unique variance, beyond IO, in predicting reading achievement scores. The sample consisted of 70 children (39 females and 31 males). Within this sample four groups of children were compared: children with reading disabilities (n=12), children with math/reading disabilities (n=19), poor readers (n=14), and skilled readers (n=25). Intelligence, reading and math tests, and verbal working memory (WM) measures were administered (presented under static and dynamic testing conditions). Two important findings emerged: (a) hierarchical regression analyses found that a dynamic assessment measure factor score contributed unique variance to predicting reading and mathematics, beyond what is attributed to verbal IQ and initial scores related to WM; and (b) poor readers and skilled readers were more likely to change and maintain their WM score gained under the dynamic testing conditions than children with reading disabilities or children with a combination of math/reading disabilities. Implications for a valid classification of reading disabilities are discussed.
Children with reading disabilities (RD) experience information-processing difficulties on specific cognitive tasks (e.g., Stanovich & Siegel, 1994; Swanson & Siegel, 2001; Torgesen, 2002). These processing difficulties are assumed to be intrinsic to the child; that is, they are not due to instructional or environmental factors (e.g., Shaywitz et al., 1999). Further, RD children's processing difficulties are reflected in specific academic domains (e.g., reading) that draw upon those processes (e.g., Swanson & Siegel, 2001; Torgesen, 2002). In addition, it is assumed that these specific processing deficits are unexpected given their overall potential (see Fletcher et al., 2002; Stanovich & Siegel, 1994; for a review of assumptions). Given these assumptions, at least two questions emerge.
First, how should "potential" be measured? The notion of potential has played a critical role in defining learning disabilities (LD) since the inception of the field (e.g., see Bateman, 1992, for review). Typically, differences between IQ and achievement on standardized tests are viewed as a prototype for representing differences between potential and actual performance (Fletcher, Francis, Rourke, Shaywitz, & Shaywitz, 1992; Shepherd, Smith, & Vojir, 1983). However, a review of the literature suggests that such procedures are invalid for classification purposes (e.g., Fletcher et al., 1992; Hoskyn & Swanson, 2000; Stuebing et al., 2002). For example, the relevance of standardized intelligence measures (e.g., WISC-III) in the diagnostic classification of learning disabilities has been criticized because reading achievement within samples with LD is not predicted by variations (high vs. low) in IQ (e.g., Fletcher et al., 2002; Hoskyn & Swanson, 2000; Stanovich & Siegel, 1994; Siegel, 1989, 1992; Stuebing et al., 2002). Further, several authors (e.g., Brown & Ferrara, 1999; Campione, 1989; Embretson, 1992) have suggested that traditional intelligence tests (i.e., tests that measure unassisted performance on global measures of academic aptitude) provide a poor estimate of general ability. These authors argue that because static or traditional approaches to assessment typically provide little feedback or practice prior to testing, failure often reflects children's misunderstanding of instructions more that their ability to perform the task. Thus, whether "potential" is adequately captured on traditional IQ measures presents a conceptual problem.
One possible alternative or supplement to traditional assessment is to measure a child's gain in performance when given examiner assistance. Thus, "potential" for learning new information (or accessing previously presented information) is measured in terms of the distance, difference between, and/or change from unassisted performance to a performance level with assistance. …