NAEP Technical DocumentationIRT Parameters for Items in the Measurement and Geometry Subscale, Grade 12 Mathematics National Assessment, by Item and Block: 2015

IRT parameters for items in the measurement and geometry subscale, grade 12 mathematics national assessment, by item and block: 2015
Block	Item	NAEP ID	a_j	b_j	c_j	d_j1	d_j2	d_j3	d_j4
M1	1	M192801	0.78	-1.71	0.19	†	†	†	†
	7	M178001	1.03	1.42	†	-0.26	0.26	†	†
	8	M196601	0.84	-0.40	0.19	†	†	†	†
M2	1	M303801	0.66	-1.08	0.20	†	†	†	†
	6	M305301	0.47	-1.80	0.20	†	†	†	†
	10	M304201	1.02	1.11	0.32	†	†	†	†
	13	M305101	1.41	0.95	0.17	†	†	†	†
M3	4	M197301	0.67	0.05	0.16	†	†	†	†
	5	M197302	0.84	-0.02	0.13	†	†	†	†
	6	M197303	1.26	1.77	†	†	†	†	†
	7	M197304	1.38	1.37	†	†	†	†	†
	10	M1975CL	0.66	1.52	†	1.65	-1.12	-1.08	0.55
M4	1	M184201	1.15	0.74	†	†	†	†	†
	7	M174901	1.58	1.48	0.12	†	†	†	†
	11	M174801	1.39	2.48	†	0.14	-0.14	†	†
	13	M180101	2.26	1.86	0.14	†	†	†	†
M5	4	M194501	0.29	-0.17	0.20	†	†	†	†
	6	M185701Z	3.29	1.54	0.34	†	†	†	†
	7	M185702	4.05	1.39	0.10	†	†	†	†
	8	M185703	1.14	1.48	†	0.43	-1.32	0.00	0.89
	11	M187701	0.65	0.72	†	-0.52	0.52	†	†
M6	6	M183401	1.09	1.94	†	-0.68	0.68	†	†
	9	M175001	0.76	-0.41	0.22	†	†	†	†
	10	M175002	0.87	1.84	†	-0.30	1.99	1.20	-2.89
	13	M182201	2.80	2.25	0.20	†	†	†	†
M7	2	M310601	0.60	1.12	0.29	†	†	†	†
	5	M309101	1.44	-0.19	0.14	†	†	†	†
	8	M304001	0.52	0.08	†	-3.28	3.28	†	†
	11	M309901	0.85	1.65	0.28	†	†	†	†
M8	2	M193801	0.92	-0.81	0.21	†	†	†	†
	4	M198601	2.01	1.33	0.10	†	†	†	†
	6	M188201	0.82	1.59	†	-0.90	0.87	-0.85	0.89
	11	M1943CL	1.13	0.75	†	0.10	-0.10	†	†
	13	M189001	0.65	1.72	†	1.85	-1.85	†	†
M9	1	M192701	0.84	0.59	0.19	†	†	†	†
	5	M190501	1.15	1.00	0.15	†	†	†	†
	8	M191901	0.91	1.15	†	0.06	-0.43	0.34	0.03
	12	M198901	1.08	1.09	†	0.71	-0.71	†	†
M10	3	M178501	0.77	1.53	†	-1.37	1.37	†	†
	6	M191701	0.70	0.52	†	0.31	-0.31	†	†
	12	M199401	1.01	0.42	0.29	†	†	†	†
	13	M1897CL	0.38	2.34	†	0.19	-0.02	-0.25	0.09
M11	2	M199501	0.86	0.43	0.23	†	†	†	†
	9	M199601	0.75	0.01	0.19	†	†	†	†
	11	M183801	0.73	2.12	0.19	†	†	†	†
	14	M176601	1.31	1.13	0.19	†	†	†	†
M12	3	M186001	0.91	0.19	†	†	†	†	†
	8	M200001	0.48	-0.18	0.22	†	†	†	†
	11	M194001	0.54	2.33	†	-0.21	0.21	†	†
	13	M185001	2.31	1.45	0.12	†	†	†	†
M13	4	M305801	1.20	-0.02	0.17	†	†	†	†
	7	M305501	1.08	-0.24	†	†	†	†	†
	9	M306501	1.08	0.08	†	†	†	†	†
	12	M305701	1.15	0.81	0.18	†	†	†	†
M14	1	M307801	0.58	-0.79	0.20	†	†	†	†
	5	M308001	0.76	0.90	†	†	†	†	†
	7	M308601	1.36	-0.13	0.17	†	†	†	†
	9	M310301	1.14	0.28	0.12	†	†	†	†
	13	M308901	1.79	1.48	0.16	†	†	†	†
† Not applicable; c parameters are not estimated for the two-parameter logistic model or generalized partial credit models, and d parameters are not estimated for two-parameter or three-parameter logistic models. NOTE: For item j, a_j represents the discriminatory power of the item, b_j represents a location parameter related to item difficulty, c_j represents the guessing parameter, and d_ji represents the category threshold parameter for category i. The c parameter value is assumed to be exactly zero and is not estimated for items scaled with the two-parameter logistic model. For item j, d_ji may not sum to zero because of rounding. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2015 Mathematics Assessment.

Last updated 17 November 2021 (ML)

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