Vocabulary Breadth and Depth in IELTS Academic Reading Tests

Some thoughts about vocabulary breadth and depth in IELTS, vocabulary threshold, and test-taking strategies.

Chen, C. & Liu, Y. (2020). The role of vocabulary breath and depth in IELTS academic reading tests. Reading in a Foreign Language, 31 (1), 1-27.

1. It is found that vocabulary breadth correlated with question types involving explicit information processing (e.g. True|False|Not Given), yet depth correlated with those that required implicit information processing (e.g. Matching Headings). To be honest, in the past it never occurred to me that vocabulary depth played such an important role in IELTS reading test. I think it was partially because for me vocabulary depth mainly refers to two things: 1)understanding the exact meaning of a word in different contexts, especially for polysemy 2)understanding a word’s collocations. (These are also the two aspects that all my English teachers in school pay most attention to.) I feel that the majority of words in IELTS reading tests show their most common meanings and there are not many difficult collocations, so I have always believed in that case vocabulary breadth is more significant. However, because this research adopts a much more comprehensive view of vocabulary depth, it is natural that the result is different from my prediction. The Word Associates Format does include tests of collocations, and the Vocabulary Knowledge Scale focuses on the core meaning of a word. In addition, there is another finding that seems to surprise both researchers and me. Vocabulary depth also correlated more highly with Sentence Completion. Previously, I thought since Sentence Completion was generally easier than other like Matching Headings and Multiple Choice, we had to just locate relevant information in articles and there was no need to truly understand it. Now this result may suggest that to finish Sentence Completion correctly, only such kind of explicit processing is not enough. Our brains actually go through more subtle implicit information processing.
2. The multiple regression analysis conducted in this study revealed that once the vocabulary size reached a certain level (6,000 in this research), a larger vocabulary was no longer the major factor improving IELTS reading test scores. A vocabulary size threshold is again corroborated. It is said that beyond this level, other abilities including test-taking strategies and grammatical knowledge become more crucial than vocabulary. My own experience is in line with this finding. The English reading test in University Entrance Examination requires a vocabulary which is easy for the majority of students. Nevertheless, there is a considerable gap between students’ scores. Our teachers thus always highlighted reading strategies and even guessing skills in class. Many classmates and I often complained that the question type called Best Title was sometimes so tricky. We were alright with summary skills, but the worst thing was, in some cases the four choices were highly similar. Even the teacher could not explain why a certain choice was correct in a logical and lucid way, and finally had to admit that there was “something wrong” with this question. I remember that we called classmates who managed to choose the right one “lucky” because we all know that all of us could understand the text but sometimes just failed to grasp “the purpose of examiners.”( “The purpose of examiners” is a popular term in English classes in my high school. Teachers attach great importance to it and consider it a significant part of test-taking strategies. If we find it hard to decide our answer to questions, especially Best Title, we are advised to guess the examiners’ purpose of asking this question, which our teachers believe can be of great help.) Nevertheless, I once discussed the problem with my classmates. What abilities are supposed to be tested in the English test in University Entrance Examination? Should the focus be on pure language skills (in the EFL context in my country, mainly receptive vocabulary and grammar, since listening and speaking are nearly completely neglected), or test-taking skills (which are already emphasized in the Chinese test)? Personally, my point is, the vocabulary and grammar can be more difficult (at least slightly), and the demand for test-taking skills can be smaller, so that students’ hard work on improving vocabulary and grammar drills which are main tasks in high school English classes can pay off.