This study aimed to describe 1-year changes in students' vocabulary in written narratives. Secondary aims included examination of accuracy and the relationship between lexical diversity and achievement. Participants included 749 students in first through eighth grades. Within-subjects 1-year change in diversity, productivity, and accuracy was…

This study explores the co-development of two related but separate reading skills, reading fluency and reading comprehension, across Grades 1-4. A bivariate biometric dual change score model was applied to longitudinal data collected from 1,784 twin pairs between the ages of 6 and 10 years. Grade 1 skills were influenced by highly overlapping…

The purpose of the present study was to investigate and rank order by importance the contributions of various cognitive predictors to reading comprehension in third, seventh, and tenth graders. An exploratory factor analysis revealed that for third grade, the best fit was a four-factor solution including fluency, verbal reasoning, nonverbal…

This study rank ordered the contributive importance of several predictors of listening comprehension for third, seventh, and tenth graders. Principal components analyses revealed that a three-factor solution with fluency, reasoning, and working memory components provided the best fit across grade levels. Dominance analyses indicated that fluency…

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…

Rates of agreement among alternative definitions of reading disability and their 1- and 2-year stabilities were examined using a new measure of agreement, the affected-status agreement statistic. Participants were 288,114 first through third grade students. Reading measures were "Dynamic Indicators of Basic Early Literacy Skills" Oral…

In this study, we examined the relationship of growth trajectories of oral reading fluency, vocabulary, phonological awareness, letter-naming fluency, and nonsense word reading fluency from 1st grade to 3rd grade with reading comprehension in 1st, 2nd, and 3rd grades. Data from 12,536 children who were followed from kindergarten to 3rd grade…