According to the hybrid model (van Bergen, van der Leij, & de Jong, 2014), the significant association among executive functioning (EF), reading, and math may be partially explained by parent-reported EF's role as a common risk and/or protective factor in reading and math (dis)abilities. The current study used a sample of 434 twin pairs…

The purpose of this study was to examine construct validity of methods of calculating lexical diversity in written narrative samples relative to children's performance on a reading vocabulary measure. For 234 children in first to fifth grade, written narratives were examined and compared between grades for number of different words (NDW), total…

Genetic and environmental relations between vocabulary and reading skills were explored longitudinally from preschool through Grades 2 and 4. At preschool there were strong shared-environment and weak genetic influences on both vocabulary and print knowledge but substantial differences in their source. Separation of etiology for vocabulary and…