Orthographic and morphological processing as predictors of reading achievement in grade 3 children

This archival study addressed two research questions. First, are Phonological Awareness (PA), Naming Speed, (NS), Orthographic Processing (OP), and Morphological Awareness (MA) distinct constructs? Second, does each of these constructs make a unique contribution to the prediction of reading ability, after controlling verbal and nonverbal intelligence?;Multiple measures of PA, NS, OP, and MA were administered to 182 Grade 3 children. Five aspects of reading ability were assessed: regular word reading, irregular word reading, pseudoword reading, reading speed, and reading comprehension. Results indicated that PA, NS, OP, and MA formed distinct factors. However, two of the MA measures loaded on both the MA and PA factors. Because of this ambiguity, z-score composites of each construct were formed. PA and NS contributed significantly to each aspect of reading after controlling for verbal and nonverbal IQ and each other. OP and MA contributed significantly to each aspect of reading after controlling for verbal and nonverbal IQ, PA, NS, and each other. These results are consistent with the Double Deficit and Dual Route theories of reading. The unique effect of MA, especially after OP, supports the hypothesized but unelaborated lexical semantic path in the Dual Route model (Castles, 2006).