Does How We Measure Vocabulary Breadth Influence its Relationship to Reading Comprehension in Young Elementary School Students?
Mount Saint Vincent University
A large body of research exists supporting the relationship between vocabulary and reading comprehension, and for younger children between vocabulary and phonological awareness. Vocabulary is frequently measured using the Peabody Picture Vocabulary Test (PPVT), and several recent studies have used shortened versions of the PPVT in explorations of oral language contributions to reading comprehension. This study examined whether these shortened versions of the PPVT are as strongly predictive of reading comprehension (in a sample of first and second grade students; N = 62) and of phonological awareness (in a sample of kindergarten and first grade students; N = 45) as the full test. A second focus of this study was on the relationship between children’s reaction times to correctly identifying items on this vocabulary measure and reading comprehension, as it has been suggested that speed of recognition may account for unique variance in children’s understanding of texts. It was found that the two shortened forms and the full version of the PPVT-5 were not differentially predictive of phonological awareness (in kindergarten and first grade students) or of reading comprehension in first grade students. However, for the second-grade students, one shortened version (every fourth item included) was not as strongly related to reading comprehension as the full version of the PPVT. Turning to the second focus of this study, reaction times to recognize vocabulary items did not explain unique variance in reading comprehension in equations which accounted for the variance explained by grade, word reading, and vocabulary breadth. Overall, the findings from this study raise questions about substituting shortened versions of the PPVT in examinations of the relationship between vocabulary and other reading measures. Furthermore, individual differences for recognizing vocabulary items may not be meaningfully related to reading comprehension in young first and second grade students; a question to be further explored in future research.