ERIC Number: EJ983903
Record Type: Journal
Publication Date: 2012-Jun
Abstractor: As Provided
Reference Count: N/A
Linking Outcomes from Peabody Picture Vocabulary Test Forms Using Item Response Models
Hoffman, Lesa; Templin, Jonathan; Rice, Mabel L.
Journal of Speech, Language, and Hearing Research, v55 n3 p754-763 Jun 2012
Purpose: The present work describes how vocabulary ability as assessed by 3 different forms of the Peabody Picture Vocabulary Test (PPVT; Dunn & Dunn, 1997) can be placed on a common latent metric through item response theory (IRT) modeling, by which valid comparisons of ability between samples or over time can then be made. Method: Responses from 2,625 cases in a longitudinal study of 697 persons for 459 unique PPVT items (175 items from Peabody Picture Vocabulary Test-Revised [PPVT-R] Form M [Dunn & Dunn, 1981], 201 items from Peabody Picture Vocabulary Test-3 [PPVT-3] Form A [Dunn & Dunn, 1997], and 83 items from PPVT-3 Form B [Dunn & Dunn, 1997]) were analyzed using a 2-parameter logistic IRT model. Results: The test forms each covered approximately plus or minus 3 SDs of vocabulary ability with high reliability. Some differences between item sets in item difficulty and discrimination were found between the PPVT-3 Forms A and B. Conclusions: Comparable estimates of vocabulary ability obtained from different test forms can be created through IRT modeling. The authors have also written a freely available SAS program that uses the obtained item parameters to provide IRT ability estimates given item responses to any of the 3 forms. This scoring resource will allow others with existing PPVT data to benefit from this work as well.
Descriptors: Item Response Theory, Test Format, Vocabulary, Comparative Analysis, Longitudinal Studies, Reliability, Difficulty Level, Test Items
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Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Authoring Institution: N/A
Identifiers - Assessments and Surveys: Peabody Individual Achievement Test; Peabody Picture Vocabulary Test