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NAEP Analysis and Scaling → Estimation of NAEP Score Scales → NAEP Assessment IRT Parameters → Science Assessment IRT Parameters → IRT Parameters for Items in the Earth and Space Sciences Subscale, Grade 4 Science Combined National and State Assessment, by Item and Block: 2015

NAEP Technical DocumentationIRT Parameters for Items in the Earth and Space Sciences Subscale, Grade 4 Science Combined National and State Assessment, by Item and Block: 2015

IRT parameters for items in the earth and space sciences subscale, grade 4 science 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
S3	1	K080101	0.77	-0.46	0.29	†	†	†	†
	10	K153001	0.59	1.42	†	0.92	-0.92	†	†
	11	K080601	0.99	0.89	0.21	†	†	†	†
	14	K080801	0.67	-1.73	0.27	†	†	†	†
	15	K106701	0.51	0.85	†	1.03	-1.03	†	†
S4	1	K079001	1.21	-0.29	0.33	†	†	†	†
	2	K078801	0.45	0.26	0.26	†	†	†	†
	9	K079301	0.40	0.08	0.13	†	†	†	†
	10	K079501	0.32	0.65	†	1.98	0.03	-2.01	†
S5	1	K086101	0.70	-0.97	0.33	†	†	†	†
	10	K0855CL	0.52	-1.19	†	0.43	0.69	-0.17	-0.95
	11	K082301	0.84	0.81	0.10	†	†	†	†
	15	K082601	1.94	1.08	0.25	†	†	†	†
S6	1	K107301	0.70	-2.06	0.16	†	†	†	†
	3	K108001	1.30	0.64	0.21	†	†	†	†
	7	K086801	0.81	-0.46	0.40	†	†	†	†
	9	K081701	0.89	-0.29	0.16	†	†	†	†
	10	K076501	0.49	0.16	†	0.86	-0.86	†	†
	12	K087501	1.04	0.78	0.27	†	†	†	†
	16	K087901	1.11	-1.36	0.19	†	†	†	†
S7	1	K165501	1.07	-1.51	0.19	†	†	†	†
	2	K165101	0.83	-0.22	0.31	†	†	†	†
	7	K160701	1.13	0.86	0.16	†	†	†	†
	11	K164701	0.71	1.84	0.26	†	†	†	†
	14	K1597CL	0.52	-0.07	†	0.74	1.18	-1.92	†
S8	2	K109901	0.58	-0.08	0.23	†	†	†	†
	6	K077701	0.42	-0.31	†	-0.26	0.26	†	†
	13	K1097CL	0.41	1.24	†	3.05	1.17	-3.47	-0.75
S9	3	K088201	0.65	1.32	0.38	†	†	†	†
	4	K088202	1.21	1.89	0.23	†	†	†	†
	8	K084601	0.49	-0.61	0.17	†	†	†	†
	12	K088951	0.67	-1.27	0.18	†	†	†	†
	13	K089001	1.21	1.44	0.33	†	†	†	†
	15	K089201	0.68	1.39	0.26	†	†	†	†
	16	K078401	0.52	1.40	0.15	†	†	†	†
S10	4	K153901	0.81	3.04	0.27	†	†	†	†
	6	K154151	0.62	0.28	0.18	†	†	†	†
	7	K083301	0.59	-0.17	0.22	†	†	†	†
	11	K081301	1.56	1.92	0.33	†	†	†	†
	16	K081401	1.18	1.03	0.32	†	†	†	†
	17	K154201	0.97	-0.18	0.24	†	†	†	†
S11	2	K1603CL	0.45	0.47	0.00	†	†	†	†
	4	K159101	0.69	0.52	0.21	†	†	†	†
	8	K1633CL	0.79	0.71	†	1.47	-1.47	†	†
	13	K165301	0.77	-0.19	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_j_i represents the category threshold parameter for category i. The c parameter 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 Science Assessment.

Last updated 17 November 2021 (ML)

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