2013 Volume 9 Issue 1 Pages 37-55
In this study, Graded Response Model(GRM) and 2 Parameter Logistic Model(2PLM) were examined to analyze the actual test data that did not satisfy the local independence assumption. And the estimates of item parameters, ability parameters, and test infomation curve obtained from these 2 models were compared. Q3(Yen, 1984) was used to assess the extent of local dependence. From the results of 2PLM, extremely large values of discrimination parameter estimates were obtained from items that had local dependence. Such a extremely values may influence the ability estimates or test information. About estimate of ability parameters, it was indicated that subjects having the same estimated ability parameter on 2PLM may have about±1vary estimated ability parameter on GRM.
