Dehghan Banadaki, Razieh

Lexical richnee (lexical density, diversity, and sophistication) and syntactic complexity in academic IELTS reading

The International English Language Testing System (IELTS) is the gatekeeper for people seeking education or profession in English-speaking countries. This exam tests the candidates’ four skills of speaking, listening, reading, and writing. Because of the scarcity of the studies done on linguistic features of Academic IELTS Reading subskill, the present study aimed to investigate lexical richness and syntactic complexity of the Academic IELTS Reading passages and the relationship between the variables. To this aim, lexical richness is further categorized to lexical density, diversity, and sophistication, and a corpus of 192 passages from 16 published practice test books was collected. The corpus analysis tool Coh-Metrix (Graesser, Mcnamara, McCarthy, & Cai, 2014) was utilized to determine each linguistic feature, and the results were compared to the results obtained for TASA norm corpora of science and social studies, because Academic IELTS Reading passages are said to be from sources available to nonspecialist readers. It was concluded that the lexicon of Academic IELTS Reading passages was about one percent denser, much more diverse, but as sophisticated as the norm corpora if age of acquisition and concreteness indices were not considered. Moreover, the syntax was seen to be more complex in three out of seven indices, as complex as the norm corpora for two indices, and less complex for the other two indices. It was also observed that syntactic complexity correlated negatively with lexical density. Significant positive correlation was found between lexical density and the other measures of lexical richness. IELTS candidates and instructors can utilize these results to enrich their IELTS preparation activities such as choice of learning and teaching material. Material developers can also use the results to provide candidates with more reliable material. Furthermore, English assessment researchers can use the results in comparative studies as well as studies related to test validity.