Lexical Threshold of L2 Reading in the Korean CSAT

For over two decades in Korea, no other English exam has been able to replace the high-stakes Korean College Scholastic Ability Test (CSAT). From a lexical perspective, there has been transient analysis of the reading passages, however, without sufficient attention it deserves as the nationally administered exam. Twenty-one years of the main CSAT of English reading texts for academic years 1994 through 2014 were utilized to compile a specialized, small corpus. For analysis, lexical richness (STTR) was calculated, and distribution of the CSAT words across the fourteen word bands of the British National Corpus (BNC) was searched with RANGE to propose a lexical threshold level. By STTR, lexical variety indicated to be steady over the twenty-one years of the CSAT. However, the recent 2014B CSAT exhibited a noticeable increase of words compared to the CSAT in previous years, pressuring test-takers to improve reading fluency. The range and the percentage of CSAT words across the 14 word bands of the BNC indicated test-takers to minimally need a threshold of 6,000 word families for 95% coverage (including proper nouns) of the CSAT reading passages. The study ends with implications for L2 vocabulary learning.