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NAEP Analysis and Scaling → Estimation of NAEP Score Scales → NAEP Assessment IRT Parameters → Mathematics Assessment IRT Parameters → IRT Parameters for Items in the Algebra Subscale, Grade 8 Mathematics Combined National and State Assessment, by Item and Block: 2015

NAEP Technical DocumentationIRT Parameters for Items in the Algebra Subscale, Grade 8 Mathematics Combined National and State Assessment, by Item and Block: 2015

IRT parameters for items in the algebra subscale, grade 8 mathematics combined national and state assessment, by item and block: 2015
Block	Item	NAEP ID	a_j	b_j	c_j	d_j1	d_j2	d_j3	d_j4
M3	1	M350201	0.72	-0.09	0.12	†	†	†	†
	5	M233601	0.40	-0.96	†	-2.00	2.00	†	†
	8	M351501	0.90	0.37	0.12	†	†	†	†
	13	M348801	0.98	0.42	0.22	†	†	†	†
M4	5	M151701	1.25	-0.04	0.22	†	†	†	†
	7	M151901	0.72	0.22	0.06	†	†	†	†
	9	M152101	0.83	0.74	0.20	†	†	†	†
	10	M152201	1.07	0.14	0.23	†	†	†	†
	13	M152501	1.77	0.82	0.13	†	†	†	†
	14	M152602	0.77	0.40	†	1.65	-2.51	0.86	†
M5	5	M221301	0.95	-0.08	0.30	†	†	†	†
	8	M221601	1.20	0.59	0.14	†	†	†	†
	10	M221801	0.97	0.52	0.21	†	†	†	†
	12	M222001	0.87	1.26	0.19	†	†	†	†
	13	M222101	1.30	2.34	0.22	†	†	†	†
M6	5	M352101	1.55	0.43	0.26	†	†	†	†
	6	M352301	0.63	-0.31	†	-1.76	1.76	†	†
	7	M350701	1.19	0.07	0.13	†	†	†	†
	14	M352501	1.74	1.27	0.22	†	†	†	†
M7	7	M355301	0.33	-1.69	†	-2.65	2.65	†	†
	11	M355601	1.23	0.87	0.15	†	†	†	†
	13	M356901	1.49	0.87	†	†	†	†	†
	15	M356701	1.05	1.38	0.20	†	†	†	†
M8	6	M238901	1.53	-0.37	0.21	†	†	†	†
	8	M237901	0.54	-0.09	†	0.09	-0.09	†	†
	10	M236501	1.29	0.31	0.07	†	†	†	†
	12	M236901	1.62	0.47	0.12	†	†	†	†
M9	5	M238501	0.67	0.06	0.24	†	†	†	†
	7	M235501	0.94	-1.15	†	†	†	†	†
	13	M234801	1.05	-0.59	0.15	†	†	†	†
	15	M2372CL	0.53	-0.15	†	0.38	1.05	-1.00	-0.43
M10	3	M222601	1.08	-0.48	0.12	†	†	†	†
	5	M222801	1.52	-0.09	0.10	†	†	†	†
	8	M223101	0.55	-0.73	†	-2.03	2.03	†	†
	11	M223401	0.39	2.62	0.36	†	†	†	†
	15	M223801	0.47	-0.02	†	-0.49	0.49	†	†
M11	6	M171001	1.34	1.49	0.48	†	†	†	†
	9	M168301	0.75	0.66	†	-0.47	0.47	†	†
	12	M164701	0.98	1.35	0.26	†	†	†	†
	14	M165201	1.70	0.97	0.15	†	†	†	†
	17	M104901	0.70	1.57	†	0.68	-0.68	†	†
M12	7	M234001	0.63	-2.51	†	†	†	†	†
	10	M232201	0.94	-0.11	0.25	†	†	†	†
	12	M232501	1.99	1.19	0.09	†	†	†	†
	14	M339701	1.38	1.03	0.12	†	†	†	†
† 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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