There is general agreement that reading fluency and reading comprehension are necessary for overall reading achievement, but how they relate to each other remains unclear. Some theories suggest that fluency is necessary for comprehension, (LaBerge & Samuels, 1974), while other theories propose that fluency is an outcome of comprehension (Goodman, 1976; Posner & Snyder, 1975). Others suggest fluency and comprehension have a reciprocal relationship (Jenkins et al., 2003). In order to provide the most effective instruction in reading fluency and comprehension, educators must know how fluency and comprehension relate to each other, and how the relation may change across grade and skill levels.

This study explored the relation between basic reading proficiency (i.e. decoding, automatic word recognition, fluency in connected text) and reading comprehension from a theoretical background using structural equation modeling (SEM). Using longitudinal data from a sub-sample of 42 students, this study examined the best predictors of basic reading proficiency and comprehension across first, third, and fifth grade. In addition, this study examined a hypothesized model of the relation between basic reading proficiency, vocabulary and verbal reasoning skills with comprehension in fifth grade, with a sub-sample of 65 students.

The strength of the relation between basic reading proficiency and comprehension was consistent across first, third, and fifth grade. In addition, basic reading proficiency and comprehension in first grade were not significantly different in their prediction of basic reading proficiency and comprehension in third grade. In third grade, basic reading proficiency is a significantly better predictor of fifth grade basic reading as compared to third grade comprehension. Lastly, the fifth grade hypothesized model did not result in a good data-model fit, and instead a two-factor model of comprehension was observed. Implications and future directions for research are discussed.