Table 3.

Simulation Results.

				Purification
				None		Partial		Full
Impact	% DIF items	Sample size	Test length	P	TIE	P	TIE	P	TIE
0	0	500	15	—	0.024	—	0.021	—	0.025
—	—	—	30	—	0.039	—	0.031	—	0.033
—	—	1,000	15	—	0.035	—	0.030	—	0.035
—	—	—	30	—	0.032	—	0.027	—	0.029
—	20	500	15	0.727	0.054	0.713	0.018	0.783	0.020
—	—	—	30	0.717	0.078	0.678	0.027	0.733	0.032
—	—	1,000	15	0.880	0.133	0.870	0.024	0.933	0.033
—	—	—	30	0.900	0.140	0.870	0.029	0.908	0.035
—	33	500	15	0.572	0.185	0.558	0.058	0.698	0.065
—	—	—	30	0.574	0.212	0.495	0.061	0.606	0.063
—	—	1,000	15	0.850	0.394	0.840	0.061	0.914	0.065
—	—	—	30	0.831	0.420	0.803	0.076	0.894	0.077
−0.5	0	500	15	—	0.023	—	0.023	—	0.030
—	—	—	30	—	0.037	—	0.030	—	0.035
—	—	1,000	15	—	0.029	—	0.026	—	0.030
—	—	—	30	—	0.033	—	0.028	—	0.030
—	20	500	15	0.597	0.037	0.587	0.016	0.710	0.025
—	—	—	30	0.618	0.078	0.555	0.030	0.650	0.034
—	—	1,000	15	0.857	0.115	0.857	0.025	0.923	0.030
—	—	—	30	0.863	0.133	0.835	0.025	0.882	0.030
—	33	500	15	0.458	0.141	0.438	0.060	0.588	0.070
—	—	—	30	0.452	0.183	0.415	0.089	0.523	0.097
—	—	1,000	15	0.752	0.357	0.714	0.074	0.848	0.077
—	—	—	30	0.761	0.388	0.745	0.099	0.862	0.100

Note. DIF = differential item functioning.