NAEP Technical DocumentationIRT Parameters for Items in the Univariate Scale, Grade 8 Science National Assessment, by Block and Item: 2019

IRT parameters for items in the univariate scale, grade 8 science DBA national assessment, by block and item: 2019
Item	NAEP ID	a	b	c	d	d	d	d
Not applicable; c parameters are not estimated for the two-parameter logistic or generalized partial credit models, and d parameters are not estimated for the two-parameter or three-parameter logistic models.
DBA = Digitally based assessment. For item j, aⱼ represents the discriminatory power of the item, bⱼ represents a location parameter related to item difficulty, cⱼ represents the guessing parameter, and dⱼᵢ 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, dⱼᵢ may not sum to zero because of rounding.
U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2019 Science Assessment.
Block S2
1	K2132MS	0.40	-0.82
2	K210401	0.59	0.27	0.23
3	K2080MS	0.27	-3.12		-6.10	6.10
4	K211001	0.85	0.24	0.34
5	K209501	0.43	1.64		-0.28	0.28
6	K2095MS	0.61	-0.58
7	K209701	0.93	1.27	0.24
8	K166201	1.15	0.23	0.18
9	K1663CL	0.69	1.29		-0.54	1.38	-0.84
10	K208901	0.82	-0.37	0.22
11	K213101	0.69	0.51	0.30
12	K210701	0.75	0.92		0.07	0.48	-0.55
13	K2083MS	0.66	0.05
14	K165801	0.45	-0.26	0.25
15	K207201	1.27	-0.39	0.26
16	K210101	2.18	0.44	0.30
17	K211201	0.80	0.93	0.28
Block S3
1	K114201	0.50	-0.14	0.36
2	K114101	0.83	1.43	0.28
3	K113901	0.52	-0.26		1.12	-1.12
4	K114001	1.10	0.33	0.30
5	K114002	1.00	0.65	0.22
6	K113401	0.46	0.65		0.10	-0.24	1.64	-1.49
7	K113201	0.47	-0.90		1.50	-1.50
8	K113102	0.63	0.71	0.28
10	K113602	1.13	1.82	0.33
11	K113603	0.70	0.85	0.17
12	K113001	0.80	-0.50	0.30
13	K113801	0.65	0.04	0.31
14	K113701	0.54	1.33		0.78	0.64	-0.21	-1.21
15	K134201	0.54	-0.23		0.44	-0.63	0.18
16	K113301	0.67	0.60	0.33
17	K113501	0.80	0.29	0.27
Block S4
1	K117801	1.22	-0.73	0.39
2	K114601	0.48	0.14		0.00	0.13	0.03	-0.16
3	K122201	1.38	1.02	0.34
4	K122301	0.73	0.43	0.19
5	K122302	0.79	-0.02	0.31
6	K122303	0.69	1.88	0.23
7	K122304	1.21	0.68	0.23
8	K116701	1.33	1.04	0.28
9	K122901	0.90	-0.10	0.27
10	K118901	1.04	-0.89	0.32
11	K122402	0.71	1.32		0.83	-0.83
12	K123001	0.51	-0.29	0.26
13	K122801	0.70	1.09		0.44	-0.44
14	K122001	1.22	0.53	0.24
15	K122602	0.51	0.16
16	K125201	0.31	0.08		-0.58	0.83	-1.32	1.08
17	K122501	0.56	0.54	0.25
18	K121801	0.90	1.55	0.21
Block S5
1	K120701	1.30	0.39	0.50
2	K120601	2.05	1.30	0.27
3	K154501	0.94	0.14	0.21
4	K121701	0.56	2.06	0.30
5	K121301	0.69	1.80		-0.23	0.20	0.02
6	K117601	0.92	1.66	0.34
7	K120801	1.49	0.94	0.20
8	K120802	0.55	0.75		0.50	-0.50
9	K124102	0.42	0.57		-1.21	1.88	-0.67
10	K154601	0.57	0.20		0.75	-0.75
11	K120901	1.09	0.30	0.19
12	K1214CL	1.48	1.25
15	K154701	0.83	1.00		2.67	-1.06	-1.61
16	K154801	0.84	-0.89	0.21
17	K121201	1.15	-0.19	0.26
18	K120501	1.31	-0.35	0.36
Block S6
1	K125101	0.30	-2.13	0.29
2	K124501	1.38	0.65	0.31
3	K124601	0.60	1.42	0.25
4	K123801	0.63	0.39		0.64	-0.30	-0.34
5	K123802	0.45	0.44		0.82	-0.82
6	K154901	0.73	1.23	0.25
7	K122101	0.53	1.28		0.86	1.09	-0.35	-1.59
8	K125001	0.84	1.24	0.33
9	K125002	0.90	0.64	0.31
10	K125003	0.48	-0.72
11	K155001	1.37	-0.44	0.31
12	K155101	1.55	1.45	0.25
13	K155201	1.08	0.24	0.25
14	K125401	0.38	1.78		1.91	-1.91
15	K125402	0.53	0.48		0.30	-0.30
16	K155301	1.41	0.63	0.36
17	K124401	0.94	0.38	0.35
Block S7
1	K2084MS	0.87	-1.58
2	K209201	0.57	0.49	0.35
3	K166801	0.68	0.70	0.20
4	K210801	0.56	1.11	0.24
5	K111301	1.26	1.03	0.26
6	K211701	0.98	0.21	0.16
7	K211702	0.50	1.68		-2.69	2.69
8	K207301	1.33	-1.11	0.32
9	K212601	1.44	0.30	0.31
10	K2076MS	0.60	-2.06
11	K2077MS	0.90	-0.18
12	K2078MS	0.68	-0.46
13	K1107CL	0.67	-0.14		1.50	-0.09	-1.41
14	K111201	0.97	0.16	0.20
15	K155401	0.98	0.52	0.24
16	K209101	1.15	-0.07	0.35
17	K212101	1.15	0.09	0.22
18	K212901	0.59	0.66		0.55	-0.55
Block S8
1	K112801	1.02	-0.34	0.30
2	K112501	0.41	0.39	0.26
3	K111901	0.60	1.48	0.31
4	K155501	1.24	0.45	0.21
5	K155502	1.36	0.49	0.20
6	K112401	0.61	1.22		-0.62	-2.11	2.73
7	K112001	1.38	0.37	0.20
8	K119701	1.16	0.56	0.28
9	K155601	0.37	2.24		-0.57	0.86	0.74	-1.03
10	K117201	0.47	-0.07	0.39
11	K117202	0.51	-0.12
12	K155751	0.57	1.15		0.34	-0.34
13	K155752	0.69	1.42		0.50	-0.50
14	K111601	0.60	0.45	0.24
15	K112901	0.60	1.43	0.23
16	K155801	1.24	-0.27	0.35
17	K112701	0.72	0.49	0.28
18	K155901	0.59	-0.18	0.23
Block S9
1	K2103MS	0.70	-0.42
2	K110101	1.06	1.27	0.35
3	K212801	1.24	0.70	0.18
4	K213501	0.66	0.75	0.28
5	K114501	1.63	1.38	0.18
6	K114802	0.54	0.45		-0.87	0.87
7	K114801	0.38	1.12		1.24	-0.12	-1.13
8	K170701	0.96	-0.23	0.35
9	K115101	0.80	-0.68	0.26
10	K210901	0.98	0.59	0.23
11	K2086MS	0.35	1.17		-0.39	0.39
12	K208605	0.76	0.63		0.86	-0.86
13	K110601	1.41	-0.69	0.18
14	K110602	0.94	0.25	0.20
15	K110603	1.17	1.30	0.29
16	K211501	1.57	0.61	0.34
18	K212201	1.15	0.17	0.26
Block S10
1	K168401	1.51	0.00	0.45
2	K170501	0.78	-1.02	0.19
3	K168301	1.30	0.73	0.20
4	K167801	0.83	0.61	0.30
5	K167901	0.85	0.43	0.24
6	K168801	0.59	-0.14	0.24
7	K166701	0.56	0.33	0.27
8	K169301	1.10	-0.05	0.24
9	K168201	0.55	0.25	0.20
10	K172101	0.99	-0.78
11	K166901	0.78	0.29	0.24
12	K165601	1.04	1.08	0.25
13	K167301	0.80	0.17	0.28
14	K167601	0.51	2.60		0.84	-0.84
15	K167701	1.05	-0.21
16	K167101	1.51	0.20	0.28
17	K170801	0.99	-0.18	0.29
18	K123901	0.64	0.63		1.31	0.66	-0.12	-1.85
Block S11
1	K165701	0.67	-1.13	0.31
2	K169201	0.64	0.74	0.16
3	K167501	0.39	-0.82	0.28
4	K169701	0.57	1.42		-0.07	0.07
5	K168101	0.93	-0.12	0.18
6	K169001	0.81	-0.32	0.16
7	K166501	0.97	0.54	0.21
8	K168701	0.62	1.18		1.05	-1.05
9	K166101	0.87	1.44		1.38	-1.38
11	K167401	0.84	-0.62	0.26
12	K167001	0.79	-0.31	0.30
13	K171201	1.61	-0.17	0.29
14	K171301	0.68	0.59		-0.54	0.54
15	K171401	1.43	0.52	0.39
16	K170601	0.90	1.23	0.28
17	K110501	0.76	0.74		1.09	-1.09
Block S12
1	K118001	0.92	-0.40	0.31
2	K156801	1.35	0.68	0.17
3	K156901	1.67	1.48	0.27
4	K118601	1.04	0.87	0.23
5	K124001	1.00	0.44	0.29
6	K116901	0.54	-0.45		-0.01	0.01
7	K123301	0.65	0.81		-0.12	0.12
8	K157001	0.87	-0.05
9	K119505	0.93	0.33
11	K123401	0.70	0.50		0.33	-0.22	-0.11
12	K112601	0.66	2.09		0.69	-0.09	0.18	-0.77
13	K118801	0.58	1.13	0.21
14	K157101	0.86	1.28	0.34
15	K115601	0.84	0.26	0.25
Block H1
1	K1913CL	0.39	-0.47		-1.29	1.29
2	K191401	1.13	0.77
3	K1917CL	0.80	-2.49		2.60	-2.60
4	K1918CL	0.93	0.93		0.21	-0.21
Block I1
1	K1871MS	0.93	0.70
2	K1872MS	0.96	0.66
3	K187302	0.84	0.26	0.27
4	K187402	0.75	-0.97	0.26
5	K187501	0.42	0.03		1.33	1.14	-2.47
6	K1876MS	0.34	1.61
7	K1877MS	0.49	-0.23
8	K187801	0.47	0.62		-0.11	0.11
9	K1879MS	0.45	-1.56		-1.23	1.23
10	K188001	0.45	-0.41		-0.57	0.57
11	K188101	0.66	1.09
Block I4
1	K1896CL	0.45	0.66		1.94	-1.94
2	K189702	0.64	0.95	0.25
3	K189902	0.53	1.38		-0.41	0.41
4	K190001	0.42	0.52		0.06	-0.06
5	K190101	0.62	0.16		0.02	-0.02
6	K190203	0.70	0.48		0.66	-0.66

IRT parameters for items in the univariate scale, grade 8 science PBA national assessment, by block and item: 2019
Item	NAEP ID	a	b	c	d	d	d	d
Not applicable; c parameters are not estimated for the two-parameter logistic or generalized partial credit models, and d parameters are not estimated for the two-parameter or three-parameter logistic models.
PBA = Paper-based assessment. For item j, aⱼ represents the discriminatory power of the item, bⱼ represents a location parameter related to item difficulty, cⱼ represents the guessing parameter, and dⱼᵢ 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, dⱼᵢ may not sum to zero because of rounding.
U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2019 Science Assessment.
Block S3
1	K114201	0.51	-0.45	0.36
2	K114101	1.08	1.20	0.30
3	K113901	0.50	-0.25		1.00	-1.00
4	K114001	0.88	0.03	0.30
5	K114002	0.81	0.53	0.21
6	K113401	0.41	0.64		-0.08	-0.13	2.04	-1.84
7	K113201	0.38	-1.12		1.61	-1.61
8	K113102	0.72	0.64	0.30
10	K113602	0.95	1.86	0.38
11	K113603	0.54	0.92	0.19
12	K113001	0.95	-0.47	0.32
13	K113801	0.61	0.02	0.31
14	K113701	0.50	1.10		0.66	0.65	-0.26	-1.05
15	K134201	0.47	-0.15		-0.23	-0.27	0.49
16	K113301	0.59	0.52	0.31
17	K113501	0.55	0.21	0.28
Block S4
1	K117801	1.20	-0.94	0.35
2	K114601	0.49	0.09		-0.19	0.31	0.04	-0.16
3	K122201	1.67	0.89	0.35
4	K122301	0.71	0.35	0.21
5	K122302	0.87	0.13	0.40
6	K122303	0.83	1.62	0.28
7	K122304	1.29	0.68	0.21
8	K116701	1.22	0.81	0.29
9	K122901	0.79	-0.35	0.21
10	K118901	0.88	-1.12	0.27
11	K122402	0.56	1.47		0.98	-0.98
12	K123001	0.87	0.47	0.28
13	K122801	0.70	0.98		0.40	-0.40
14	K122001	1.28	0.51	0.24
15	K122602	0.44	1.34		-0.04	0.04
16	K125201	0.33	0.24		-0.04	0.65	-1.72	1.10
17	K122501	0.48	0.45	0.24
18	K121801	1.07	1.49	0.23
Block S5
1	K120701	1.00	0.11	0.44
2	K120601	1.43	1.46	0.31
3	K154501	1.08	0.11	0.25
4	K121701	0.51	2.05	0.30
5	K121301	0.58	1.85		-0.32	0.12	0.21
6	K117601	1.15	1.55	0.37
7	K120801	1.15	0.94	0.22
8	K120802	0.31	1.69		-0.39	0.39
9	K118501	0.54	0.95		1.29	-0.05	-1.24
10	K154601	0.43	0.18		0.65	-0.65
11	K120901	1.06	0.41	0.20
12	K121401	0.74	0.01	0.29
13	K121402	0.96	-0.01	0.31
14	K121403	2.00	1.32	0.11
15	K154701	0.57	1.18		3.08	-0.55	-0.50	-2.03
16	K154801	0.93	-0.79	0.25
17	K121201	1.25	-0.20	0.30
18	K120501	1.37	-0.42	0.30
Block S6
1	K125101	0.36	-1.33	0.27
2	K124501	1.44	0.49	0.26
3	K124601	0.73	1.59	0.30
4	K123801	0.68	0.38		0.55	-0.26	-0.29
5	K123802	0.44	0.28		0.79	-0.79
6	K154901	0.70	0.92	0.24
7	K122101	0.44	1.25		0.63	1.34	-0.08	-1.89
8	K125001	0.89	1.30	0.32
9	K125002	0.98	0.76	0.31
10	K125003	0.35	0.67		0.64	-0.64
11	K155001	1.45	-0.41	0.33
12	K155101	1.62	1.33	0.24
13	K155201	1.03	0.22	0.27
14	K125401	0.46	1.54		1.42	-1.42
15	K125402	0.47	0.27		0.45	-0.45
16	K155301	1.25	0.44	0.35
17	K124401	0.95	0.11	0.32
Block S7
1	K111301	1.24	0.98	0.27
2	K117401	1.23	0.65	0.13
3	K155401	0.79	0.23	0.23
4	K1107CL	0.59	-0.43		1.65	-0.07	-1.58
5	K114501	1.35	1.35	0.18
6	K110601	1.27	-0.67	0.36
7	K110602	0.88	0.25	0.28
8	K110603	1.49	1.23	0.27
9	K123901	0.49	0.69		1.19	1.52	-0.26	-2.45
10	K110401	0.41	1.00		-0.54	0.48	0.06
12	K110501	0.68	1.14		0.90	-0.90
13	K121001	0.82	1.44		0.31	-0.31
14	K1210CL	0.39	0.50		-1.20	2.23	-1.03
15	K110801	1.34	1.29	0.26
16	K110101	1.44	1.28	0.35
Block S8
1	K112801	1.13	-0.39	0.37
2	K112501	0.42	0.55	0.30
3	K111901	0.83	1.61	0.44
4	K155501	1.19	0.40	0.18
5	K155502	1.40	0.35	0.19
6	K112401	0.66	1.17		-0.42	-2.18	2.61
7	K112001	1.42	0.34	0.18
8	K119701	1.36	0.47	0.26
9	K155601	0.32	2.35		-1.25	1.23	1.38	-1.36
10	K117201	0.59	-0.07	0.36
11	K117202	0.53	0.00
12	K155751	0.63	1.44		0.45	-0.45
13	K155752	0.45	1.20		-0.25	1.06	-0.81
14	K111601	0.70	0.33	0.22
15	K112901	0.69	1.39	0.23
16	K155801	1.46	-0.27	0.35
17	K112701	0.79	0.27	0.26
18	K155901	0.52	-0.22	0.27
Block S9
1	K115101	0.85	-0.50	0.25
2	K114401	1.24	0.36	0.19
3	K115201	0.71	0.79		0.06	0.74	-0.81
4	K114901	1.08	0.41	0.23
5	K1560CL	0.73	1.17
6	K156101	0.46	1.87		-1.90	2.01	-0.11
7	K115501	1.51	1.47	0.17
8	K114802	0.58	0.24		-0.54	0.54
9	K114801	0.38	1.68		-1.46	2.51	-1.05
10	K115301	1.18	-0.32	0.38
12	K124102	0.43	0.55		-1.41	1.80	-0.39
13	K111401	0.88	0.94	0.21
14	K156201	0.92	0.43	0.34
Block S10
1	K168401	1.40	-0.11	0.47
2	K170501	0.80	-1.20	0.18
3	K168301	1.44	0.70	0.20
4	K167801	1.04	0.42	0.38
5	K167901	1.05	0.42	0.33
6	K168801	0.52	-0.12	0.30
7	K166701	0.61	0.17	0.26
8	K169301	1.35	-0.10	0.38
9	K168201	0.55	0.44	0.18
10	K172101	0.91	-1.06
11	K166901	0.71	0.06	0.20
12	K165601	1.07	0.91	0.23
13	K167301	0.88	0.09	0.26
14	K167601	0.48	1.66
15	K167701	0.93	-0.13
16	K167101	1.68	0.12	0.24
17	K170801	1.22	-0.17	0.30
Block S11
1	K165701	0.84	-1.03	0.36
2	K169201	0.72	0.44	0.15
3	K167501	0.43	-1.29	0.24
4	K169701	0.53	1.26		-0.46	0.46
5	K168101	0.93	-0.15	0.20
6	K169001	0.91	-0.45	0.23
7	K166501	1.07	0.59	0.22
8	K168701	0.63	1.04		1.07	-1.07
9	K166101	0.79	1.25		1.43	-1.43
10	K167201	0.46	0.00	0.22
11	K167401	1.04	-0.34	0.39
12	K167001	0.86	-0.49	0.29
13	K171201	1.38	-0.51	0.26
14	K171301	0.59	0.46		-0.71	0.71
15	K171401	1.14	0.25	0.33
16	K170601	1.01	1.09	0.27
Block S12
1	K118001	0.80	-0.55	0.32
2	K156801	1.40	0.61	0.18
3	K156901	1.29	1.48	0.26
4	K118601	1.30	1.09	0.16
5	K124001	1.04	0.36	0.25
6	K116901	0.49	-0.56		-0.24	0.24
7	K123301	0.78	0.23
8	K157001	0.61	1.10		1.20	-1.20
9	K119505	0.84	0.13
10	K124301	0.44	1.45	0.15
11	K123401	0.64	0.46		0.32	-0.36	0.04
12	K112601	0.70	1.90		0.75	-0.75
13	K118801	0.59	0.98	0.21
14	K157101	0.79	1.12	0.32
15	K115601	0.98	0.31	0.32

Last updated 05 December 2023 (SK)

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​​​NAEP Technical DocumentationIRT Parameters for Items in the Univariate Scale, Grade 8 Science National Assessment, by Block and Item: 2019

NAEP Technical DocumentationIRT Parameters for Items in the Univariate Scale, Grade 8 Science National Assessment, by Block and Item: 2019