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A Computer Program for Estimating Examinee Ability and Item Characteristic Curve Parameters

Lord, Frederic M.; Wingersky, Marilyn S.
Publication Year:
Report Number:
ETS Research Memorandum
Document Type:
Page Count:
Subject/Key Words:
National Science Foundation (NSF), Office of Naval Research, Computer Software, Item Analysis, Mathematical Models, Psychometrics


The major problem in estimating the item characteristic curve parameters is the large number of parameters. The estimation procedure is considered converged when the parameter estimates become less than the errors of calculation; convergence is a slow process. The computer program is written in Fortran IV, and the only input required are the item responses for each examinee. Final output contains the estimated item parameters and abilities. Examples and formulas for models are included as are item response input and output.

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