Table 4.

Estimates of Item Parameters and Expected Item Difficulties for Test Form A, Before and After Their Rescaling Onto the Scale of Base Form B.

Item	Form A: Before rescaling				Form A: After rescaling
	a	b	c	δ	a*	b*	c*	δ*
1	0.859	−0.112	0.374	0.295	0.792	−0.278	0.347	0.282
2	0.658	0.089	0.240	0.395	0.636	−0.029	0.232	0.380
3	0.741	0.276	0.299	0.396	0.727	0.153	0.289	0.381
4	1.024	0.124	0.247	0.403	0.954	0.014	0.239	0.383
5	0.985	−1.012	0.222	0.186	0.954	−1.102	0.221	0.174
6	0.871	−1.415	0.218	0.138	0.847	−1.514	0.217	0.129
7	0.982	0.687	0.204	0.545	0.929	0.644	0.202	0.535
8	0.927	−1.409	0.221	0.132	0.897	−1.511	0.220	0.122
9	0.731	−1.220	0.216	0.185	0.710	−1.316	0.215	0.175
10	0.545	−1.115	0.243	0.224	0.528	−1.215	0.241	0.216
11	0.932	−0.751	0.205	0.242	0.904	−0.835	0.204	0.229
12	0.899	−1.474	0.262	0.120	0.869	−1.581	0.260	0.111
13	0.621	−0.828	0.233	0.254	0.601	−0.916	0.232	0.244
14	1.062	−0.702	0.186	0.248	1.030	−0.783	0.185	0.234
15	1.075	−0.493	0.230	0.276	1.042	−0.571	0.228	0.263
16	1.164	−0.690	0.199	0.240	1.129	−0.770	0.199	0.226
17	0.785	0.292	0.190	0.463	0.753	0.235	0.188	0.451
18	0.476	1.050	0.247	0.508	0.471	1.008	0.256	0.496
19	0.802	−0.369	0.215	0.321	1.047	−0.403	0.212	0.304
20	1.182	0.548	0.170	0.550	1.372	0.392	0.163	0.523

Note. Given in boldface are the numbers of seven items used as common items with the base test form B; (Items 1, 2, 3, 4, 18, 19, and 20 in form A are used as Items 1, 2, 3, 4, 11, 12, and 13, respectively, in the base test form B; see Table 3).