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NAEP Analysis and Scaling → Estimation of NAEP Score Scales → NAEP Assessment IRT Parameters → IRT Parameters for the Mathematics Assessments → IRT Parameters for Items in the Algebra Scale, Grade 8 Mathematics Combined National and State Assessments, By Item and Block: 2011

NAEP Technical DocumentationIRT parameters for the algebra scale, grade 8 mathematics combined national and state assessments, by item and block: 2011
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 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), 2011 Mathematics Assessment.
MC 8 M150501 1.03 0.67 0.25 † † † †
9 M150601 1.02 1.71 0.08 † † † †
11 M150801 0.50 1.77 † -1.74 1.74 † †
14 M151101 1.25 0.43 0.04 † † † †
15 M151201 0.59 1.02 † † † † †
MD 5 M151701 1.10 -0.07 0.19 † † † †
7 M151901 0.68 0.21 0.05 † † † †
9 M152101 0.67 0.69 0.17 † † † †
10 M152201 1.05 0.18 0.21 † † † †
13 M152501 1.95 1.00 0.13 † † † †
14 M152602 0.77 0.43 † 1.76 -2.56 0.80 †
ME 5 M221301 0.78 -0.05 0.28 † † † †
8 M221601 1.06 0.63 0.13 † † † †
10 M221801 0.99 0.65 0.25 † † † †
12 M222001 0.83 1.51 0.20 † † † †
13 M222101 1.71 2.45 0.23 † † † †
MF 2 M140501 1.52 -0.26 0.22 † † † †
6 M140901 0.78 -0.01 0.09 † † † †
12 M141501 1.12 -0.07 0.27 † † † †
16 M141901 0.45 1.58 † 2.20 1.06 -0.83 -2.43
MG 6 M169401 1.02 0.62 0.19 † † † †
10 M164201 0.93 1.28 0.15 † † † †
11 M170201 1.27 0.64 0.31 † † † †
12 M165301 0.96 0.68 † 0.11 -0.11 † †
MH 3 M163301 1.00 -0.32 0.26 † † † †
5 M164501 0.91 -0.15 0.11 † † † †
12 M166601 0.87 0.30 0.15 † † † †
15 M1699CL 0.52 -0.38 † 0.69 2.00 -0.20 -2.49
MI 3 M170601 0.51 -0.95 0.07 † † † †
10 M170701 1.39 0.58 0.24 † † † †
11 M165001 0.77 1.28 † † † † †
13 M170801 0.80 2.24 † -1.83 1.83 † †
MJ 3 M222601 0.93 -0.61 0.06 † † † †
5 M222801 1.44 -0.11 0.06 † † † †
8 M223101 0.52 -0.76 † -2.11 2.11 † †
11 M223401 0.42 2.46 0.33 † † † †
15 M223801 0.47 0.34 † -0.63 0.63 † †
MK 6 M171001 0.92 1.61 0.47 † † † †
9 M168301 0.73 0.70 † -0.49 0.49 † †
12 M164701 0.96 1.62 0.27 † † † †
14 M165201 1.56 1.15 0.17 † † † †
17 M104901 0.70 1.55 † 0.72 -0.72 † †
ML 5 M153101 0.99 0.38 0.21 † † † †
7 M153301 1.54 1.02 0.13 † † † †
9 M153501 0.58 -0.87 0.10 † † † †
10 M153601 0.79 -0.97 † † † † †
12 M153801 1.76 0.87 0.13 † † † †
15 M154101 0.90 0.67 0.23 † † † †
17 M154301 1.96 1.22 0.17 † † † †
Last updated 30 June 2014 (GF)
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