A longitudinal study of phonological and orthographic knowledge and processing abilities: Their causal roles in reading acquisition

This study was conducted to investigate the causal relationships among phonological and orthographic knowledge and processing abilities and word reading ability. One hundred first grade children participated in the study from Time 1 (November, 1989) to Time 2 (April, 1989). Each child was tested at both times with a battery of tasks to measure phonological and orthographic knowledge and processing abilities, word reading ability, and intelligence (at Time 1 only). Principal components analysis was used to empirically define these constructs. Three separate path analyses were conducted: (1) The causal effects of prior phonological and orthographic knowledge and processing abilities, word-reading ability, intelligence, and digit span performance on subsequent word-reading ability were tested. A large direct effect of prior word-reading ability was found. Prior phonological knowledge and processing ability had a small direct effect. (2) The causal effects of these variables on subsequent phonological knowledge and processing ability were tested. A large direct effect of prior phonological knowledge and processing ability was found. Prior orthographic knowledge and processing ability had a small direct effect. (3) The causal effects of these variables on subsequent orthographic knowledge and processing ability were tested. A large direct effect of prior orthographic knowledge and processing ability was found. Vocabulary had a small direct effect. It is suggested that the causal models presented in this study are a more accurate reflection of these abilities than other studies, because autoregression effects (i.e., effects of the variable at Time 1 on itself at Time 2) are taken into consideration. The importance of critical time periods in reading acquisition is discussed.