What Text Features Make Reading Comprehension Difficult Across Elementary School? Investigating Difficulty and Changes in Difficulty

Beginning readers benefit in most situations from reading activities that are neither too difficult nor too easy. This study investigated which text features make reading comprehension difficult for third and fourth grade elementary school students. Specifically, 145 multiple-choice items from a reading comprehension test used in several cross-sectional studies (G3: N = 1387; G4: N = 868) and a longitudinal sub-study (N = 195) were analyzed using explanatory item response models to explain item difficulty and changes in item difficulty across grades. A multi-step feature selection procedure controlling for seven task features led to the selection of eight text features from a total of 268 linguistic text features examined. The results showed that lexical and syntactic features and text genre were the most relevant features and that the importance of specific text features changes from third to fourth grade. Expository text were more difficult on average than narrative texts. This difference was only partially explained by lexical and syntactic features in third grade, but almost completely in fourth grade. The results suggest that text features have a dynamic effect on reading comprehension difficulty throughout third to fourth grade; this is especially true of text genre. Our results can help to select more appropriate texts for elementary students and to improve our understanding of the complex interaction between reader, text and activity as it develops over time.