Analysis of Bilingual Children's Performance on the English and Spanish Versions of the Woodcock-Muñoz Language Survey-R (WMLS-R)
The purpose of this study was to investigate the way in which items on the Woodcock-Muñoz Language Survey Revised (WMLS-R) Spanish and English versions function for bilingual children from different ethnic subgroups who speak different dialects of Spanish. Using data from a sample of 324 bilingual Hispanic families and their children living on the United States mainland, differential item functioning (DIF) was conducted to determine if test items in English and Spanish functioned differently for Mexican, Cuban, and Puerto Rican bilingual children. Data on child and parent language characteristics and children's scores on Picture Vocabulary and Story Recall subtests in English and Spanish were collected. DIF was not detected for items on the Spanish subtests. Results revealed that some items on English subtests displayed statistically and practically significant DIF. The findings indicate that there are differences in the difficulty level of WMLS-R English-form test items depending on the examinees' ethnic subgroup membership. This outcome suggests that test developers need to be mindful of potential differences in performance based on ethnic subgroup and dialect when developing standardized language assessments that may be administered to bilingual students.
Construct Validity and Measurement Invariance of the Peabody Picture Vocabulary Test-III Form A in the Performance of Struggling Adult Readers: Rasch Modeling
PURPOSE: The aim of this study was to apply the Rasch model to an analysis of the psychometric properties of the PPVT-III Form A items with struggling adult readers. METHODS: The PPVT-IIIA was administered to 229 African-American adults whose isolated word reading skills were between third and fifth grades. Conformity of the adults' performance on the PPVT-III items was evaluated using the Winsteps software. RESULTS: Analysis of all PPVT-IIIA items combined did not fully support its use as a useful measure of receptive vocabulary for struggling adult readers who were African Americans. To achieve an adequate model fit, items 73 through item 156 were analyzed. The items analyzed showed adequate internal consistency reliability, unidimensionality, and freedom from differential item functioning for ability, gender, and age, with a minor modification. DISCUSSION: With an appropriate treatment of misfit items, the results supported the measurement properties, internal consistency reliability, unidimensionality of the PPVT-IIIA items, and measurement invariance of the test across subgroups of ability, age, and gender.
Identifying Developmental Language Disorder in School age Bilinguals: Semantics, Grammar, and Narratives
Children with Developmental language disorder (DLD) have particular difficulty learning language despite otherwise general normal development. When school age bilingual children struggle with language, a common question is if the difficulties they present reflect lack of ability or lack of language experience. To address the question of identification of DLD in the context of bilingualism, we explore the diagnostic accuracy of measures administered in two languages. The Bilingual English Spanish Assessment Middle Extension (BESA-ME) assesses semantics and morphosyntax and the Test of Narrative Language (TNL) assesses comprehension and production of narratives. These measures were administered to 112 second graders (19 with DLD) and 64 fourth graders (7 with DLD). We explored the classification accuracy of each of these measures alone and in combination using receiver operator characteristic (ROC) curve analysis. The ROC curve illustrates diagnostic classification of a measure at various cutpoints. We compared the extent to which measures in English, Spanish, or best language account for area under the (ROC) curve. Discriminant function analysis using the best indicator (Spanish, English, best language) from each type of measure (semantics, morphosyntax, narrative) in combination demonstrate classification accuracy above 80%. Morphosyntax in the best language was the strongest predictor of DLD for second grade children. In fourth grade, the three measures contributed more equally in predicting DLD.
