A Correlation Survey Between YL and Lexile Scores in Books for Extensive Reading

A Proposal for a Revised Conversion Table

Abstract

The Yomiyasusa Level (YL) is a readability measurement given for Japanese readers to de- velop their extensive reading (ER) practices. It is, however, rarely used outside of Japan, and even in Japan, many international teachers are apparently not familiar with this measure- ment. One possible reason for this is the paucity of explanation in English on what YL is and the meaning of its scores. If they are unclear, it will be difficult for teachers to guide students using this framework. This study investigated the YL and Lexile scores of 2,984 books from 43 series from August to October 2020. The purpose of this research was to explore the cor- relation between the scores in the two readability measurements by adopting a more robust method and to revise the YL to Lexile conversion table proposed by the author’s previous study. The YL scores were taken from an ER guidebook by Furukawa and Kanda (2013), and the Lexile scores were obtained using the Lexile search tool, Find a Book. The correlation between the two scores based on nearly 3,000 books was high (r = .73), and it was considered possible to revise the conversion table. When revising, several YL bundles within a range were made, and the means of Lexile were obtained from the books that were categorized in each bundle. Furthermore, the Lexile conversions with a range were estimated for each bundle so that approximately 80% of the books in the bundle would fit in the range. By categorizing and bundling, the revised version of the YL to Lexile conversion table was proposed in the range of YL 0.1 – YL 6.5, and 120L – 1070L. This conversion table shows an approximate conversion from Lexile to YL, and vice versa. The table can also be used to incorporate more materials whose Lexile scores are available in ER by converting them into YL estimates, which may expand the possibility of more diverse ER practices.