This study explored the relationship between the reading ability and science achievement of students in grades 5, 8, and 9. Reading ability was assessed with four measures: word recognition, vocabulary, syntactic knowledge, and comprehension (23% of all passages were on science topics). Science achievement was assessed with state…

The current study uses a crossed random-effects item response model to simultaneously examine both reader and word characteristics and interactions between them that predict the reading of 39 morphologically complex words for 221 middle school students. Results suggest that a reader's ability to read a root word (e.g., "isolate") predicts that…