ERIC Number: EJ1438127
Record Type: Journal
Publication Date: 2024-Mar
Pages: 22
Abstractor: As Provided
ISBN: N/A
ISSN: ISSN-0272-2631
EISSN: EISSN-1470-1545
Evaluating Evidence for the Reliability and Validity of Lexical Diversity Indices in L2 Oral Task Responses
Studies in Second Language Acquisition, v46 n1 p278-299 2024
Although lexical diversity is often used as a measure of productive proficiency (e.g., as an aspect of lexical complexity) in SLA studies involving oral tasks, relatively little research has been conducted to support the reliability and/or validity of these indices in spoken contexts. Furthermore, SLA researchers commonly use indices of lexical diversity such as Root TTR (Guiraud's index) and D (vocd-D and HD-D) that have been preliminarily shown to lack reliability in spoken L2 contexts and/or have been consistently shown to lack reliability in written L2 contexts. In this study, we empirically evaluate lexical diversity indices with respect to two aspects of reliability (text-length independence and across-task stability) and one aspect of validity (relationship with proficiency scores). The results indicated that neither Root TTR nor D is reliable across different text lengths. However, support for the reliability and validity of optimized versions of MATTR and MTLD was found.
Descriptors: Second Language Learning, Second Language Instruction, Oral Language, Validity, Reliability, Language Proficiency, Vocabulary Skills, Task Analysis, Speech Communication, Computational Linguistics, Written Language, Scores, Correlation, Indexes
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Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
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