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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 Algebra Scale, Grade 8 Mathematics Combined National and State Assessment, By Item and Block: 2013
NAEP Technical DocumentationIRT parameters for items in the algebra scale, 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 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 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 8 M150501 1.19 0.66 .29 † † † †
9 M150601 1.02 1.63 .09 † † † †
11 M150801 0.51 1.73 † -1.64 1.64 † †
14 M151101 1.25 0.40 .05 † † † †
15 M151201 0.61 0.90 † † † † †
MD 5 M151701 1.19 -0.06 .23 † † † †
7 M151901 0.68 0.18 .05 † † † †
9 M152101 0.70 0.71 .17 † † † †
10 M152201 1.01 0.10 .21 † † † †
13 M152501 1.74 0.91 .14 † † † †
14 M152602 0.78 0.42 † 1.70 -2.43 0.73 †
ME 5 M221301 0.83 -0.12 .27 † † † †
8 M221601 1.06 0.54 .12 † † † †
10 M221801 0.95 0.56 .23 † † † †
12 M222001 0.86 1.39 .20 † † † †
13 M222101 1.45 2.39 .22 † † † †
MF 2 M140501 1.47 -0.33 .21 † † † †
6 M140901 0.76 -0.11 .08 † † † †
12 M141501 1.10 -0.18 .26 † † † †
16 M141901 0.44 1.56 † 2.23 1.09 -0.82 -2.50
MG 6 M169401 1.08 0.60 .20 † † † †
10 M164201 0.94 1.27 .17 † † † †
11 M170201 1.19 0.48 .30 † † † †
12 M165301 0.98 0.65 † 0.14 -0.14 † †
MH 6 M238901 1.41 -0.38 .21 † † † †
8 M237901 0.51 -0.09 † 0.09 -0.09 † †
10 M236501 1.18 0.30 .08 † † † †
12 M236901 1.52 0.50 .13 † † † †
MI 5 M238501 0.65 0.06 .22 † † † †
7 M235501 0.88 -1.24 † † † † †
13 M234801 0.96 -0.63 .15 † † † †
15 M2372CL 0.52 -0.19 † 0.38 1.09 -1.04 -0.44
MJ 3 M222601 0.94 -0.64 .06 † † † †
5 M222801 1.43 -0.17 .07 † † † †
8 M223101 0.54 -0.78 † -2.07 2.07 † †
11 M223401 0.40 2.46 .34 † † † †
15 M223801 0.48 0.17 † -0.58 0.58 † †
MK 6 M171001 1.02 1.63 .47 † † † †
9 M168301 0.72 0.66 † -0.50 0.50 † †
12 M164701 0.90 1.50 .26 † † † †
14 M165201 1.50 1.04 .15 † † † †
17 M104901 0.69 1.55 † 0.71 -0.71 † †
ML 7 M234001 0.63 -2.40 † † † † †
10 M232201 0.86 -0.13 .21 † † † †
12 M232501 1.79 1.22 .09 † † † †
14 M339701 1.24 1.03 .11 † † † †
Last updated 21 May 2017 (DC)
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