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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 Physical Science Subscale, Grade 4 Science Combined National and State Assessment, by Item and Block: 2015

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

IRT parameters for items in the physical science 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	2	K080001	0.55	0.88	0.22	†	†	†	†
	5	K080301	0.44	-0.03	0.12	†	†	†	†
	6	K080302	0.81	0.90	0.39	†	†	†	†
	7	K080404	0.66	1.13	†	0.78	-0.78	†	†
	16	K081001	1.39	0.31	0.25	†	†	†	†
	17	K081201	1.18	0.90	0.16	†	†	†	†
S4	4	K078902	0.60	1.32	†	2.40	-2.40	†	†
	11	K086401	0.61	-2.67	0.15	†	†	†	†
	12	K079801	1.46	1.17	0.14	†	†	†	†
S5	2	K081501	1.11	0.86	0.20	†	†	†	†
	5	K081801	0.46	1.53	†	0.36	-0.36	†	†
	8	K082102	1.34	1.44	0.10	†	†	†	†
	9	K082103	0.27	2.12	0.21	†	†	†	†
	16	K084202	0.76	2.13	†	0.10	-0.10	†	†
	17	K084208	1.24	0.86	0.27	†	†	†	†
S6	2	K086501	1.38	1.02	0.40	†	†	†	†
	6	K107902	0.59	0.77	†	0.62	-0.62	†	†
	8	K0869CL	0.51	-0.90	†	1.02	-0.85	-0.17	†
	13	K109102	0.44	2.00	†	1.10	-1.10	†	†
	15	K087701	1.21	0.67	0.18	†	†	†	†
S7	3	K162301	0.72	-2.30	0.21	†	†	†	†
	4	K1642CL	0.46	-0.63	†	1.94	1.67	-3.61	†
	6	K163401	0.80	-1.99	0.27	†	†	†	†
	8	K159001	1.90	0.77	0.22	†	†	†	†
	12	K162501	1.55	0.71	0.30	†	†	†	†
	13	K160601	0.95	1.07	0.15	†	†	†	†
S8	3	K077501	0.44	-0.89	†	0.51	-0.51	†	†
	5	K106501	1.02	2.24	0.09	†	†	†	†
	7	K108501	1.20	1.51	0.23	†	†	†	†
	9	K078102	0.33	1.33	†	-0.04	-2.03	2.07	†
	10	K078103	0.37	3.04	0.24	†	†	†	†
	15	K078301	0.56	0.52	†	0.76	-0.76	†	†
S9	7	K088401	0.55	1.66	†	2.03	0.91	0.47	-3.41
	10	K109401	0.36	-1.86	0.24	†	†	†	†
	11	K109402	0.75	1.57	†	-1.34	1.34	†	†
S10	2	K083701	0.65	-0.14	0.13	†	†	†	†
	5	K154001	0.35	1.97	0.00	†0.37	-0.37	†	†
	8	K083302	0.92	1.34	0.31	†	†	†	†
	12	K083601	0.47	-0.16	0.17	†	†	†	†
	13	K085301	1.19	0.86	0.16	†	†	†	†
	14	K085302	0.51	1.09	†	1.06	-1.06	†	†
S11	3	K165401	0.88	-1.87	0.20	†	†	†	†
	9	K161901	0.72	-0.34	0.16	†	†	†	†
	10	K160001	2.87	1.10	0.14	†	†	†	†
	11	K160101	1.28	0.63	0.37	†	†	†	†
	12	K160201	1.09	0.90	0.31	†	†	†	†
† 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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