Large-scale Assessments in Education

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Table 2 Item difficulty and discrimination parameters used for data generation

From: Effects of DIF in MST routing in ILSAs

	Stage
	Module	Core	1		2
	Module	Core	Easy	Difficult	Easy	Moderate	Difficult
Difficulty parameter	i1	0.318	0.533	0.533	0.260	0.260	0.260
	i2	0.742	0.253	0.253	0.818	0.818	0.818
	i3	0.635	0.266	0.266	0.256	0.256	0.256
	i4	0.247	− 0.052	0.977	− 0.079	0.260	2.163
	i5	0.652	0.048	1.000	− 0.075	0.818	1.472
	i6	0.684	0.013	0.900	− 0.259	0.256	1.517
	i7	0.505	0.112	1.037	− 0.105	0.488	1.313
	i8	0.752	0.190	1.127	− 0.140	0.704	1.450
	i9	0.613	− 0.030	0.887	− 0.251	0.674	1.582
	i10	0.759	0.039	0.885	− 0.231	0.759	1.178
	i11	0.453	0.164	1.050	− 0.174	0.646	1.397
	i12	0.646	0.154	1.105	− 0.224	0.779	1.498
Discrimination parameter	i1	1.473	0.910	0.910	1.045	1.045	1.045
	i2	1.976	0.683	0.683	1.030	1.030	1.030
	i3	1.316	0.705	0.705	1.143	1.143	1.143
	i4	1.126	1.459	1.754	0.692	1.045	0.580
	i5	1.344	0.659	0.874	0.915	1.030	1.890
	i6	1.152	1.098	1.553	1.226	1.143	1.148
	i7	0.855	1.333	1.530	0.681	0.765	1.313
	i8	1.545	1.248	1.326	1.306	1.599	1.237
	i9	1.204	1.352	1.650	1.186	1.764	1.398
	i10	1.399	0.513	1.388	0.821	1.399	1.058
	i11	1.158	1.376	1.147	1.136	1.676	1.577
	i12	1.676	1.389	2.166	0.912	1.136	1.706

Note: Under Stages 1 and 2, the first three items are trend items and therefore are contained in each module of a respective stage. Bold parameters represent trend items that are repeated in each module within a stage.

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