The relationship between lexical diversity and EFL writing proficiency

This study investigates the lexical dimension of EFL writing by exploring the relationship between lexical diversity and EFL writing proficiency. The relationship is explored through an analysis of forty-five email texts written by Chinese high school students that were taken from a Chinese National Matriculation English Test (NMET) practice writing test. Type-token ratio (TTR) and D (a measurement of lexical diversity through curve fitting) were used to establish indices of lexical diversity. The results showed that the lexical diversity of email texts graded at higher proficiency levels was not significantly different from the lexical diversity of email texts graded at lower proficiency levels, and that neither the TTR nor D measures had a statistically significant relationship with participants’ writing scores. These findings suggest that lexical diversity measures do not always offer a reliable basis for distinguishing between writing proficiency levels.