PROJECT SUMMARY/ABSTRACT Poor reading comprehension is a longstanding problem in the U.S. that has not improved over the past two decades. Poor reading comprehension causes children to struggle academically, to drop out of school, to earn less over their lifetime, and puts them at high risk for poor health outcomes (National Academy of Sciences, 2004). Our long-term goal is to develop methods for preventing and treating reading comprehension problems by understanding the changing structure of reading across development and the cognitive, psychological, and ecological mechanisms that contribute to reading comprehension outcomes. We will continue our longitudinal study of reading comprehension, conducted by the Language and Reading Research Consortium (LARRC), with two groups of children - those who entered preschool speaking primarily English and those who entered preschool as Spanish-English dual-language learners. We will also recruit new groups of 6th and 10th grade monolingual English and Spanish-English bilingual students for cross-sectional studies. We will address the following specific aims: (1) Determine which language, cognitive, and pre-reading skills in preschool and kindergarten, or growth in these skills from preschool to kindergarten, most accurately predicts reading comprehension in grade 6; (2) Determine whether there are children with late emerging reading comprehension problems in grade 6 and if so, whether they can be identified using language, cognitive, and pre-reading measures from PK or K; (3) Determine the factor structure for reading comprehension in grades 6 and 10 to assess whether a single-factor model of reading comprehension is sufficient or whether additional factors are required to take into account text type (i.e., narrative versus expository) and measurement type (i.e., processing versus product), and whether there are differences between grades; (4) Determine whether a new model of reading that includes multiple indicators for cognitive, psychological, and ecological factors better predicts reading comprehension in grades 6 and 10 than models with fewer factors and indicators examined in prior literature.; and (5) Determine whether findings for Aims 1-4 differ for children who entered preschool speaking English and children who entered preschool as Spanish-English dual-language learners. This project is innovative in the length of time we follow students (preschool through grade 6), the breadth and depth of cognitive, psychological, and ecological skills assessed, and the study of both English and Spanish-English bilingual students using both longitudinal and cross-sectional samples. Results will positively impact our ability to identify children at risk for poor reading comprehension, even before they learn to read, and will provide a sound basis for the development and testing of reading comprehension assessments, curricula, and interventions for older students and DLLs.