Effect of Item Parameter Drift in Mixed Format Common Items on Test Equating

The aim of the study was to examine common items in mixed format (e.g., multiple-choices and essay items) contain parameter drifts test equating processes performed with item non-equivalent groups design. In this study, which carried out using Monte Carlo simulation a fully crossed design, factors length (30 50), sample size (1000 3000), ratio 40%), drift (IPD) (20 30%), location tests (at beginning, randomly distributed, at end) IPD multiple-choice (low [0.2] high [1.0]) were studied. Four forms created, two do not drifts. After on first other forms, again second form. Test results compared root mean squared error (RMSE) value. As result research, items, ratio, errors found be significant.