Psychometric Evaluation of Lexical Diversity Indices in Spanish Narrative Samples From Children With and Without Developmental Language Disorder.

Purpose The purpose of the current study was to examine construct validity evidence for the following 4 lexical diversity measures for use in Spanish narrative samples of children with developmental language disorder and typical language development (TLD): (a) type-token ratio (TTR; Chotlos, 1944 ; Templin, 1957 ), (b) hypergeometric distribution D ( McCarthy & Jarvis, 2010 ), (c) measure of textual lexical diversity (MTLD; McCarthy, 2005 ), and (d) moving-average TTR (MATTR; Covington & McFall, 2010 ). Method A multiple-group, confirmatory factor analytic stepwise procedure was applied to examine factorial invariance in a sample of 435 monolingual Spanish-speaking children (335 with TLD and 100 with specific language impairment). Results MATTR was the strongest indicator of the lexical diversity of a sample and demonstrated measurement invariance across children with TLD and specific language impairment.