Abstract
The purpose of this paper is to investigate the effects of lexical richness on item difficulty (the percentage of correct answers) of the listening test of English proficiency administered by the National Center Test for University Admission or Daigaku Nyugakusha Senbatsu Daigaku Nyushi Center Shiken in 2008 (the 2008 Center Listening Test). The analyses were conducted based on data from 4,699 third-grade high school students in the report of Benesse Corporation (2008). Of the three aspects showing lexical richness (sophistication, diversity and density), only lexical density had a significant moderate negative correlation with item difficulty. The results suggest that some of the items taking the form of a short dialogue tend to show high lexical density and that high lexical density can hinder the listening comprehension of test-takers. Some suggestions for future test construction are drawn from these findings.
