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NAEP Analysis and ScalingEstimation of NAEP Score ScalesNAEP Assessment IRT ParametersMathematics Assessment IRT Parameters → IRT Parameters for Items in the Data Analysis, Statistics, and Probability Subscale, Grade 8 Mathematics Combined National and State Assessment, by Block and Item: 2019

​​​NAEP Technical DocumentationIRT Parameters for Items in the Data Analysis, Statistics, and Probability Subscale, Grade 8 Mathematics Combined National and State Assessment, by Block and Item: 2019

IRT parameters for items in the data analysis, statistics, and probability subscale, grade 8 mathematics combined national and state assessment, by block and item: 2019
ItemNAEP IDabcdd
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.
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 Mathematics Assessment.
Block M1
4M2482010.56-1.850.16
11M3841MS0.901.05
Block M2
11M3801MS0.430.70
Block M3
4M4047MS0.22-2.23
7M4088MS0.56-1.07-1.011.01
Block M4
8M3497011.060.990.23
14M3522010.820.260.16
16M3494011.091.230.16
18M2222010.531.710.12
Block M5
6M2229011.270.280.15
10M2233010.481.300.09-0.09
13M2236011.150.820.15
21M1523010.402.190.11
Block M6
8M1711011.520.590.14
12M1518010.64-0.780.12
15M1679010.571.63-1.041.04
Block M7
8M2362010.89-0.660.15
11M2315010.610.74
16M2219010.930.860.21
Block M8
2M3883000.94-0.171.91-1.91
5M3869011.500.620.17
Block M9
4M2533010.81-0.210.09-0.09
7M4143011.16-0.100.19
13M3513011.460.970.17
Block M10
3M2353010.901.140.22
11M2368011.250.610.25
14M3510010.630.290.19
19M2390011.18-0.520.70-0.70
Block M11
1M2529011.32-1.490.17
8M2502010.99-1.49
Block M12
5D2490MS0.83-1.71
11M3844020.622.061.56-1.56
Block M13
2M4074010.49-1.540.14
5M3893MS0.51-0.88-0.900.90
Block M14
7M3866MS0.62-0.550.76-0.76
15M4113MS0.1111.74


Last updated 05 December 2023 (SK)