Abstract
The goal of this study was (1) to investigate the development of decoding (efficiency), reading comprehension, vocabulary and spelling during the elementary school years and (2) to determine the differences between poor, average and good performers with regard to the development of these skills. Twice each year two standardized tests for each skill were administered. For two successive periods, one of the tests for each skill was the same. To describe the development in terms of a latent variable evolving across grades, the structured-means version of the structural equation model was used. The growth was expressed in terms of effect size. With respect to the first question, clear seasonal effects were found for reading comprehension, vocabulary and spelling, while the seasonal effect for decoding efficiency was restricted to the early grades. Progress tended to be greater from fall to spring than from spring to fall. For decoding efficiency, and to a lesser degree for vocabulary and spelling, growth showed a declining trend across grades. For reading comprehension, the progress in grade 2 was lower than the progress in grade 3, but progress was declining across higher grades. With respect to the second question, it appeared that initially low performers on reading comprehension, vocabulary and spelling tended to show a greater progress, especially in periods where the largest amount of instruction was given. Although it was found that the low, medium and high ability groups remain in the same order, as far as their means are concerned, these findings do not confirm the existence of a Matthew effect for reading comprehension, vocabulary and spelling. For decoding efficiency no clear differential effect could be found: the gap between the poor and good performers did not widen over time for this skill.
