ERIC Number: ED389724
Record Type: Non-Journal
Publication Date: 1991-Feb
Reference Count: N/A
An Alternative Three-Parameter Logistic Item Response Model.
Pashley, Peter J.
Birnbaum's three-parameter logistic function has become a common basis for item response theory modeling, especially within situations where significant guessing behavior is evident. This model is formed through a linear transformation of the two-parameter logistic function in order to facilitate a lower asymptote. This paper discusses an alternative three-parameter logistic model in which the asymptote parameter is a linear component within the logit of the function. This alternative is derived from a more general four-parameter model based on a transformed hyperbola. (Contains 7 figures, 1 appendix of likelihood equations and information functions, and 13 references.) (Author)
Publication Type: Reports - Evaluative
Education Level: N/A
Authoring Institution: Educational Testing Service, Princeton, NJ.