. 2016 Feb 16;76(6):954–975. doi: 10.1177/0013164416631100

Table 3.

Item Parameters and D-Scores for 3 Examinees on 20 Test Items of GAT-V Base Form, B.

	Item parameters (3PL)				X-scores			D-scores
Item	a_i	b_i	c_i	δ_i	X _i1	X_i ₂	X_i ₃	D_i ₁	D_i ₂	D_i ₃
1	0.792	−0.278	0.347	.282	1	0	1	.282	0	.282
2	0.636	−0.029	0.232	.380	1	1	1	.380	.380	.380
3	0.727	0.153	0.289	.381	1	0	1	.381	0	.381
4	0.954	0.014	0.239	.383	0	1	1	0	.383	.383
5	0.612	2.634	0.264	.674	1	0	1	.674	0	.674
6	1.040	−1.052	0.216	.176	1	0	1	0	0	.176
7	0.908	−1.429	0.223	.131	0	0	1	0	0	.131
8	1.017	0.600	0.215	.523	0	1	1	0	.523	.523
9	0.932	−1.453	0.224	.125	0	1	1	0	.125	.125
10	0.778	−1.236	0.216	.176	0	0	1	0	0	.176
11	0.471	1.008	0.256	.496	0	1	1	0	.496	.496
12	1.047	−0.403	0.212	.304	0	0	1	0	0	.304
13	1.372	0.392	0.163	.523	0	0	1	0	0	.523
14	0.988	0.547	0.179	.534	0	0	1	0	0	.534
15	1.100	−0.592	0.200	.264	0	0	1	0	0	.264
16	1.019	−1.059	0.196	.181	0	0	1	0	0	.181
17	0.879	−0.814	0.234	.226	0	0	1	0	0	.226
18	0.674	−0.024	0.187	.402	0	0	1	0	0	.402
19	1.761	3.463	0.116	.883	0	0	1	0	0	.883
20	1.008	−0.499	0.211	.285	0	0	1	0	0	.285
Total	7.327	5	5	20	1.717	1.907	7.327

Note. GAT-V = General Aptitude Test–Verbal; 3PL = three-parameter logistic. δ_i = expected item difficulty (the population proportion of incorrect item responses). Column D_is is the product of columns X_is and δ_i; that is, D_is = δ_iX_is; (i = 1, . . ., 20; s = 1, 2, 3). The D-score of person s is the sum of the entries in column D_is; that is, D_s = D_1s+⋯+D_20s. The maximum possible D-score (for all item responses correct) is D_max = δ₁+⋯+δ₂₀ = 7.327. Given in boldface are the numbers of seven items in the base form, B, which are used as common items with the new test form, A (see Table 4).