This project sheds light on the morphemes and grammatical structures used at different band levels, as well as on the error rates and types associated with their use. The authors provide information that is relevant for examiner and teacher training, and make suggestions for improving rating scales and exam tasks.
A sample of 73 IELTS Speaking tests from band levels 4 to 8 was analysed in order to identify grammatical structures that distinguish different band levels and to calculate the error rates which characterise their use.
The results showed that different features followed different paths. Although some features, such as plural -s, were acquired early, others, like the irregular past, seemed to follow a path of gradual improvement from bands 4 to 8, while one, namely third person -s, was found to undergo dramatic improvement only at bands 7 and 8. These findings bear some interesting similarities to patterns observed in second language acquisition studies.
A second focus of this study was to characterise the range of more complex structures attempted by candidates at different levels, centring on the use of conditionals, relative clauses, indirect questions and passive structures. It was found that attempts at these structures did indeed tend to increase at higher band levels, though this was often
accompanied by a high failure rate.
This study contributes to our understanding of the order in which grammatical morphemes and complex structures are acquired, while at the same time providing useful information for IELTS examiners, teachers and course book writers on what structures candidates are likely to produce and what errors are typical of candidates at different levels.