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

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

IRT parameters for items in the life 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	3	K077602	0.54	0.23	†	0.85	-0.35	-0.50	†
	4	K077603	0.98	1.67	0.32	†	†	†	†
	8	K080501	1.04	-0.09	0.27	†	†	†	†
	9	K080502	0.52	1.07	0.25	†	†	†	†
	12	K153101	0.90	0.92	0.21	†	†	†	†
	13	K153102	0.26	4.95	0.00	†	†	†	†
S4	3	K078701	0.95	0.94	0.06	†	†	†	†
	5	K084301	0.57	0.45	0.00	†	†	†	†
	6	K084302	0.80	0.08	0.00	†	†	†	†
	7	K153201	0.60	-2.09	0.29	†	†	†	†
	8	K153301	0.71	-0.01	†	0.75	-0.75	†	†
	14	K084401	0.83	-0.21	0.19	†	†	†	†
	15	K153401	0.73	-0.96	0.45	†	†	†	†
S5	3	K081601	0.57	2.13	†	-0.27	0.27	†	†
	4	K087301	0.47	-0.46	†	1.23	-1.23	†	†
	6	K081901	1.28	2.52	0.16	†	†	†	†
	12	K153501	0.75	1.27	0.21	†	†	†	†
	13	K153502	0.84	0.95	0.27	†	†	†	†
	14	K082501	0.42	-0.17	†	1.20	-1.20	†	†
S6	4	K086601	0.41	1.47	0.29	†	†	†	†
	5	K086602	0.67	1.06	0.25	†	†	†	†
	11	K087402	0.26	1.41	†	3.44	-0.11	-3.33	†
	14	K108701	0.65	-1.52	0.24	†	†	†	†
S7	5	K162201	0.78	-2.55	0.13	†	†	†	†
	9	K164801	1.23	-1.96	0.19	†	†	†	†
	10	K164901	0.54	-1.43	†	1.25	-1.25	†	†
	15	K162401	0.63	-3.86	0.25	†	†	†	†
S8	1	K078601	0.80	-1.90	0.17	†	†	†	†
	8	K109301	0.97	1.34	0.23	†	†	†	†
	11	K082401	1.05	1.33	0.41	†	†	†	†
	12	K082402	1.31	1.62	0.27	†	†	†	†
	14	K078201	1.13	0.30	0.20	†	†	†	†
	16	K085801	1.34	-0.26	0.19	†	†	†	†
S9	1	K088701	0.14	-6.51	0.27	†	†	†	†
	2	K088001	0.92	-0.12	0.35	†	†	†	†
	5	K088301	0.28	-3.57	0.28	†	†	†	†
	6	K088302	0.37	-0.47	†	2.05	-2.05	†	†
	9	K109501	1.12	0.66	0.23	†	†	†	†
	14	K1537CL	0.48	-0.83	†	0.31	1.82	-2.14	†
S10	1	K153801	0.40	-3.50	0.23	†	†	†	†
	3	K0829CL	0.54	-0.50	†	2.36	1.56	-1.87	-2.05
	9	K083501	0.70	-0.97	0.26	†	†	†	†
	10	K083502	0.45	0.59	†	1.59	-1.59	†	†
	15	K083402	0.48	1.25	†	0.79	1.19	-1.98	†
S11	1	K161301	0.61	-1.77	0.16	†	†	†	†
	5	K163901	1.10	-2.02	0.22	†	†	†	†
	6	K164001	1.32	-1.46	0.24	†	†	†	†
	7	K164101	1.19	-1.63	0.28	†	†	†	†
	14	K162001	0.90	0.21	0.30	†	†	†	†
† 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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