Abstract
Broadly, individuals' cognitive abilities influence their academic skills, but the significance and strength of specific cognitive abilities varies across academic domains and may vary across age. Simultaneous analyses of data from many tests and cross-battery analyses can address inconsistent findings from prior studies by creating comprehensively defined constructs, which allow for greater generalizability of findings. The purpose of this study was to examine the cross-battery direct effects and developmental differences in youths' cognitive abilities on their basic reading abilities, as well as the relations between their reading and writing achievement. Our sample included 3927 youth aged 6 to 18. Six intelligence tests (66 subtests) and three achievement tests (10 subtests) were analyzed. Youths' general intelligence (g, large direct and indirect effects), verbal comprehension-knowledge (large direct effect), working memory (large direct effect), and learning efficiency (moderate direct effect) explained their basic reading skills. The influence of g and fluid reasoning were difficult to separate statistically. Most of the cognitive-basic reading relations were stable across age, except the influence of verbal comprehension-knowledge (Gc), which appeared to slightly increase with age. Youths' basic reading had large influences on their written expression and spelling skills, and their spelling skills had a large influence on their written expression skills. The directionality of the effects most strongly supported the direct effects from the youths' basic reading to their spelling skills, and not vice versa.