ERIC Number: EJ1067921
Record Type: Journal
Publication Date: 2015-Jun
Abstractor: As Provided
Item Response Theory Modeling of the Philadelphia Naming Test
Fergadiotis, Gerasimos; Kellough, Stacey; Hula, William D.
Journal of Speech, Language, and Hearing Research, v58 n3 p865-877 Jun 2015
Purpose: In this study, we investigated the fit of the Philadelphia Naming Test (PNT; Roach, Schwartz, Martin, Grewal, & Brecher, 1996) to an item-response-theory measurement model, estimated the precision of the resulting scores and item parameters, and provided a theoretical rationale for the interpretation of PNT overall scores by relating explanatory variables to item difficulty. This article describes the statistical model underlying the computer adaptive PNT presented in a companion article (Hula, Kellough, & Fergadiotis, 2015). Method: Using archival data, we evaluated the fit of the PNT to 1- and 2-parameter logistic models and examined the precision of the resulting parameter estimates. We regressed the item difficulty estimates on three predictor variables: word length, age of acquisition, and contextual diversity. Results: The 2-parameter logistic model demonstrated marginally better fit, but the fit of the 1-parameter logistic model was adequate. Precision was excellent for both person ability and item difficulty estimates. Word length, age of acquisition, and contextual diversity all independently contributed to variance in item difficulty. Conclusions: Item-response-theory methods can be productively used to analyze and quantify anomia severity in aphasia. Regression of item difficulty on lexical variables supported the validity of the PNT and interpretation of anomia severity scores in the context of current word-finding models.
Descriptors: Item Response Theory, Scores, Difficulty Level, Test Items, Naming, Models, Regression (Statistics), Aphasia, Communication Disorders, Morphology (Languages), Computation, Predictor Variables, Context Effect, Age Differences, Language Impairments, Language Skills
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Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Sponsor: US Department of Veterans Affairs
Authoring Institution: N/A
Grant or Contract Numbers: C7476W