The relationships of different levels of phonological processing (sounds in heard and spoken words for whole words, syllables, phonemes, and rimes) to multi-leveled functional reading or writing systems were studied. Participants in this cross-sectional study were students in fourth-grade (n = 119, mean age 116.5 months) and sixth-grade (n = 105,…

Research on the development of reading skills through the primary school years has pointed to the importance of individual differences in initial ability as well as the growth of those skills. Additionally, it has been theorized that reading skills develop incrementally. The present study examined the genetic and environmental influences on 2…

Alternative models of the structure of individual and developmental differences of written composition and handwriting fluency were tested using confirmatory factor analysis of writing samples provided by first- and fourth-grade students. For both groups, a five-factor model provided the best fit to the data. Four of the factors represented…