Recent reading research has identified three reader variables involved in fluent reading: automatic word identification, contextual word identification, and text phrasing. To confirm the validity of these variables in the reading process, to test reading models employing them in an integrated and interactive manner, and to identify developmental changes in the models, a study was undertaken involving 77 third grade and 65 fifth grade students. The students read orally a social studies passage and identified within-sentence breaks in the passage. After a buffer task, they were asked to retell all they could remember from the passage, then completed a multiple choice comprehension measure and a standardized reading achievement test. A model using the variables was then hypothesized, fitted to the study data, and tested using structural equation modeling. The findings suggest that the variables are valid surface level factors involved in fluent reading, that they interact in leading to comprehension, and that the nature of their interrelationship was not static, since developmental changes occurred. (FL)