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ERIC Number: EJ1067963
Record Type: Journal
Publication Date: 2015-Jun
Pages: 13
Abstractor: As Provided
ISSN: ISSN-1092-4388
Psychometric Evaluation of Lexical Diversity Indices: Assessing Length Effects
Fergadiotis, Gerasimos; Wright, Heather Harris; Green, Samuel B.
Journal of Speech, Language, and Hearing Research, v58 n3 p840-852 Jun 2015
Purpose: Several novel techniques have been developed recently to assess the breadth of a speaker's vocabulary exhibited in a language sample. The specific aim of this study was to increase our understanding of the validity of the scores generated by different lexical diversity (LD) estimation techniques. Four techniques were explored: D, Maas, measure of textual lexical diversity, and moving-average type-token ratio. Method: Four LD indices were estimated for language samples on 4 discourse tasks (procedures, eventcasts, story retell, and recounts) from 442 adults who are neurologically intact. The resulting data were analyzed using structural equation modeling. Results: The scores for measure of textual lexical diversity and moving-average type-token ratio were stronger indicators of the LD of the language samples. The results for the other 2 techniques were consistent with the presence of method factors representing construct-irrelevant sources. Conclusion: These findings offer a deeper understanding of the relative validity of the 4 estimation techniques and should assist clinicians and researchers in the selection of LD measures of language samples that minimize construct-irrelevant sources.
American Speech-Language-Hearing Association (ASHA). 10801 Rockville Pike, Rockville, MD 20852. Tel: 800-638-8255; Fax: 301-571-0457; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: National Institute on Aging (DHHS/NIH)
Authoring Institution: N/A
Grant or Contract Numbers: R01AG029476