ERIC Number: ED207996
Record Type: Non-Journal
Publication Date: 1981-Jul
Reference Count: N/A
An Upper Asymptote for the Three-Parameter Logistic Item-Response Model.
Barton, Mark A.; Lord, Frederic M.
An upper-asymptote parameter was added to the three-parameter logistic item response model. This four-parameter model was compared to the three-parameter model on four data sets. The fourth parameter increased the likelihood in only two of the four sets. Ability estimates for the students were generally unchanged by the introduction of the fourth parameter. (Author)
Publication Type: Reports - Research
Education Level: N/A
Sponsor: Office of Naval Research, Arlington, VA. Personnel and Training Research Programs Office.
Authoring Institution: Educational Testing Service, Princeton, NJ.