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Abstract:
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In this report we give a brief introduction to Item Response Theory models and multilevel models . The general assumptions of two classical Item Response Theory , 1PL and 2PL models are discussed . We follow the discussion by introducing a multilevel level framework for these two Item Response Theory Models . We explain Bock and Aitkin's (1981 ) work to estimate item parameters for these two models . Finally we illustrate these models with a LSAT exam data and two statistical softwares ; R project and Stata . |