Unraveling the longitudinal relations between math reasoning and reading: The contributions of reading comprehension, word reading, and reading speed.

Despite extensive discussion on the relation between math and reading, few studies have explored how fundamental math and reading abilities contribute to each other's development. This study investigated the relations between math reasoning and three reading-related measures (i.e., reading comprehension, word reading, and reading speed). Using a cohort-sequential design that spanned kindergarten to grade 9, 673 children from four cohorts (Mage = 5.67, 7.81, 10.03, and 12.28) were assessed annually over 4 years. A random intercept cross-lagged panel model showed that within-person deviations in math reasoning predicted deviations in reading comprehension and reading speed, but not word reading. These findings underscore the unidirectional influence of math reasoning on specific reading abilities at key developmental stages, with no reciprocal relationships observed.