NAEP Technical DocumentationIRT Parameters for Items in the Data Analysis, Statistics, and Probability Subscale, Grade 4 Mathematics Combined National and State Assessment, by Item and Block: 2015

IRT parameters for items in the data analysis, statistics, and probability subscale, grade 4 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	13	M344901	1.00	0.78	0.39	†	†	†	†
M4	7	M147301	0.72	-0.79	0.24	†	†	†	†
	10	M147601	0.57	1.23	0.14	†	†	†	†
	12	M147801	1.29	0.47	0.12	†	†	†	†
M5	6	M218701	0.87	-1.00	0.15	†	†	†	†
M5	7	M218801	1.18	-0.45	†	†	†	†	†
M6	6	M340301	1.27	0.45	0.25	†	†	†	†
M7	3	M346101	0.68	-0.29	†	0.48	-0.48	†	†
M7	16	M348301	1.11	1.85	†	†	†	†	†
M8	2	M240301	0.56	-3.04	0.19	†	†	†	†
	6	M230501	1.38	0.65	0.40	†	†	†	†
	10	M231001	0.92	0.51	0.29	†	†	†	†
M9	6	M338401	0.29	-1.72	†	-2.72	2.72	†	†
M9	10	M225001	0.80	0.32	†	1.03	-1.03	†	†
M10	7	M220301	0.78	-0.44	0.06	†	†	†	†
M10	10	M220601	0.42	1.63	0.11	†	†	†	†
M11	12	M154901	0.02	5.28	0.09	†	†	†	†
M11	14	M162301	0.73	0.64	0.09	†	†	†	†
M12	7	M225201	0.61	-0.42	†	-3.18	3.18	†	†
† 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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