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NAEP Analysis and Scaling → Estimation of NAEP Score Scales → NAEP Assessment IRT Parameters → Mathematics Assessment IRT Parameters → IRT Parameters for Items in the Geometry Subscale, Grade 8 Mathematics Combined National and State Assessment, By Item and Block: 2013
NAEP Technical DocumentationIRT parameters for items in the geometry subscale, grade 8 mathematics combined national and state assessment, by item and block: 2013
Block Item NAEP ID aj bj cj dj1 dj2 dj3  dj4 
† 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, 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.
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2013 Mathematics Assessment.
MC 3 M150001 1.02 0.70 .48 † † † †
6 M150301 1.32 0.33 .12 † † † †
MD 1 M151301 0.90 -0.71 .10 † † † †
3 M151501 0.74 -0.37 † 0.28 -0.28 † †
ME 3 M221203 0.56 0.91 † 2.33 -2.33 † †
7 M221501 0.70 -1.53 .20 † † † †
MF 3 M140601 0.69 -1.42 .22 † † † †
9 M141201 0.82 0.71 .21 † † † †
11 M141401 0.62 0.81 .18 † † † †
14 M141701 0.89 0.98 .12 † † † †
MG 4 M170101 0.18 -0.63 † -5.27 5.27 † †
7 M168201 0.80 0.35 .16 † † † †
15 M168401 0.92 1.88 .11 † † † †
MH 2 M237101 1.79 1.03 .25 † † † †
11 M236701 1.86 1.04 .13 † † † †
15 M3173CL 1.01 1.21 † 0.56 -0.56 † †
MI 2 M235901 1.13 0.46 .11 † † † †
9 M238301 0.85 0.41 .08 † † † †
MJ 4 M222701 0.56 -0.09 † -3.56 3.56 † †
14 M223701 2.13 1.37 .17 † † † †
MK 2 M170901 1.01 -0.36 .20 † † † †
10 M169101 0.96 2.07 .35 † † † †
16 M171201 1.03 1.09 .16 † † † †
ML 3 M339501 1.21 -0.35 .20 † † † †
4 M232001 0.65 0.28 .09 † † † †
15 M234201 0.57 1.12 † -0.94 0.94 † †
Last updated 21 May 2017 (DC)
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