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NAEP Analysis and ScalingEstimation of NAEP Score ScalesNAEP Assessment IRT ParametersScience Assessment IRT Parameters → IRT Parameters for Items in the Life Science Subscale, Grade 4 Science National Assessment, by Block and Item: 2019

​​​NAEP Technical DocumentationIRT Parameters for Items in the Life Science Subscale, Grade 4 Science National Assessment, by Block and Item: 2019

IRT parameters for items in the life science subscale, grade 4 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, a represents the discriminatory power of the item, b represents a location parameter related to item difficulty, c represents the guessing parameter, and d 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 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 K204401 0.52 -2.11 0.24
5 K1999MS 0.93 -0.37
6 K1999CL 0.51 0.98 0.84 -0.84
8 K0829CL 0.49 -0.01 2.71 0.98 -1.93 -1.76
15 K153401 0.55 -0.09 0.31
Block S3
3 K077602 0.60 0.89 0.40 -0.42 0.01
4 K077603 1.21 1.78 0.31
8 K080501 1.16 0.03 0.21
9 K080502 0.44 1.24 0.16
12 K153101 1.08 0.81 0.16
13 K153102 0.28 5.24
Block S4
2 K201901 0.80 -1.61 0.20
3 K201902 0.83 -1.46 0.20
4 K201903 1.08 0.75 0.20
8 K203101 0.39 -0.07 -0.13 0.13
12 K083402 0.53 1.29 1.92 0.63 -2.55
Block S5
3 K081601 0.75 1.72 0.28 -0.28
4 K087301 0.52 -0.18 1.21 -1.21
6 K081901 1.23 2.33 0.19
12 K153501 1.14 1.33 0.28
13 K153502 0.87 1.07 0.27
14 K082501 0.55 -0.13 1.20 -1.20
Block S6
4 K086601 0.38 1.38 0.23
5 K086602 0.56 0.99 0.22
11 K087402 0.36 1.27 2.35 -0.14 -2.21
14 K108701 0.69 -1.51 0.24
Block S7
5 K162201 0.95 -1.76 0.20
9 K164801 1.07 -1.85 0.21
10 K164901 1.06 -1.85
15 K162401 0.55 -3.41 0.24
16 K153301 0.84 0.30 0.64 -0.64
Block S8
1 K078601 0.95 -1.24 0.24
7 K109301 1.12 1.24 0.21
10 K082401 0.53 0.99 0.30
11 K082402 1.02 1.69 0.28
13 K078201 1.48 0.42 0.32
15 K085801 1.49 -0.22 0.17
Block S9
1 K088701 0.33 -2.06 0.22
2 K088001 0.99 -0.16 0.34
5 K088301 0.47 -2.24 0.23
6 K088302 0.44 -0.21 1.72 -1.72
9 K109501 1.39 0.66 0.23
14 K1537CL 0.53 -0.48 0.37 1.53 -1.91
Block S10
1 K153201 0.70 -1.87 0.23
5 K083501 0.69 -1.31 0.27
6 K083502 0.49 0.41 1.10 -1.10
11 K203801 0.82 -0.47 0.17
12 K203802 0.92 -0.65 0.15
16 K203201 0.80 -1.56 0.23
Block S11
1 K161301 0.61 -1.41 0.23
5 K163901 1.20 -1.79 0.23
6 K164001 1.35 -1.29 0.24
7 K164101 1.31 -1.26 0.20
14 K162001 1.02 0.33 0.30
15 K084301 0.61 0.70
16 K084302 0.83 0.13
Block H2
1 K185801 0.75 -0.17 0.87 -0.87
2 K185901 1.19 -0.04 0.69 -0.69
3 K186101 1.02 0.19 0.56 -0.56
4 K186201 0.57 2.71 0.41 -0.41
5 K1863CL 0.36 1.34 -2.89 3.24 -0.36
Block I1
1 K1805MS 0.43 -3.84 -0.39 0.39
2 K180602 0.36 -1.40 0.24
5 K180902 0.51 1.27 1.42 -1.42
10 K181403 0.39 2.03 1.02 -1.02


IRT parameters for items in the life science subscale, grade 4 science PBA national assessment, by block and item: 2019
ItemNAEP IDabcdddd
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, a represents the discriminatory power of the item, b represents a location parameter related to item difficulty, c represents the guessing parameter, and d 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 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
3K0776020.510.300.90-0.31-0.59
4K0776030.671.770.26
8K0805011.05-0.140.24
9K0805020.541.140.25
12K1531011.000.830.21
Block S4
3K0787011.121.000.08
5K0843010.580.49
6K0843020.850.08
7K1532010.55-2.420.25
8K1533010.70-0.050.76-0.76
14K0844010.86-0.030.24
15K1534010.64-1.260.33
Block S5
3K0816010.551.91-0.010.01
4K0873010.47-0.451.22-1.22
6K0819011.112.760.18
12K1535010.901.340.25
13K1535020.840.890.26
14K0825010.44-0.201.15-1.15
Block S6
4K0866010.501.320.30
5K0866020.820.940.27
11K0874020.291.283.09-0.02-3.07
14K1087010.72-1.320.27
Block S7
5K1622010.89-2.140.23
9K1648011.22-1.820.25
10K1649011.11-1.91
15K1624010.70-3.620.26
Block S8
1K0786010.91-1.570.27
4K0799010.792.190.36
8K1093011.061.290.22
11K0824010.761.390.38
12K0824020.991.700.25
14K0782011.200.280.23
16K0858011.36-0.150.22
Block S9
1K0887010.25-3.410.27
2K0880011.01-0.200.36
5K0883010.33-2.850.28
6K0883020.39-0.421.98-1.98
9K1095011.180.710.25
14K1537CL0.49-0.870.351.79-2.13
Block S10
1K1538010.43-3.450.26
3K0829CL0.53-0.232.151.45-1.68-1.92
9K0835010.80-0.770.27
10K0835020.530.551.36-1.36
15K0834020.471.241.191.20-2.39
Block S11
1K1613010.59-1.660.23
5K1639011.10-1.940.24
6K1640011.32-1.480.23
7K1641011.13-1.650.24
14K1620011.060.320.35


Last updated 05 December 2023 (SK)