Predicting word reading ability: a quantile regression study

Abstract

Predictors of early word reading are well established. However, it is unclear if these predictors hold for readers across a range of word reading abilities. This study used quantile regression to investigate predictive relationships at different points in the distribution of word reading. Quantile regression analyses used preschool and kindergarten measures of letter knowledge, phonological awareness, rapid automatised naming, sentence repetition, vocabulary and mother's education to predict first‐grade word reading. Predictors generally varied in significance across levels of word reading. Notably, rapid automatised naming was a significant unique predictor for average and good readers but not poor readers. Letter knowledge was generally a stronger unique predictor for poor and average readers than good readers. Well‐known word reading predictors varied in significance at different points along the word reading distribution. Results have implications for early identification and statistical analyses of reading‐related outcomes.What is already known about this topic Early predictors of word reading are well established, with letter knowledge, phonological awareness and rapid automatised naming identified as key predictors. These relationships are primarily investigated in average readers, or in groups of good and poor readers separated by an arbitrary cut‐off score. What this paper adds In this study, we used quantile regression to determine significant predictors of word reading across a range of word reading abilities. The quantile regression approach avoids the loss of power that can arise when creating subgroups and has none of the issues associated with the use of a single, arbitrary cut-off score to separate good and poor readers. Letter knowledge and phonological awareness were significantly predictive of word reading across the distribution of word reading abilities, whereas rapid automatised naming was significant only for good readers, and sentence recall was significant only for poor readers. Implications for theory, policy and practice Results reinforce the usefulness of measures such as letter knowledge, phonological awareness and sentence repetition in the early identification of children at risk for reading disabilities. Results also suggest that measures of rapid naming may add little unique information in differentiating between children who subsequently read in the below‐average range.