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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 Data Analysis, Statistics, and Probability Subscale, Grade 8 Mathematics Combined National and State Assessment, By Item and Block: 2013
NAEP Technical DocumentationIRT parameters for items in the data analysis, statistics, and probability 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 2 M149901 0.59 0.06 † 0.76 -0.76 † †
7 M150401 0.77 -0.17 .28 † † † †
10 M150701 0.91 0.17 .14 † † † †
MD 6 M151801 0.60 -1.19 .12 † † † †
11 M152301 0.30 2.33 .09 † † † †
ME 11 M221901 0.58 0.77 .12 † † † †
14 M222201 0.68 1.32 .12 † † † †
MF 4 M140701 0.68 0.01 .20 † † † †
13 M141601 0.90 0.53 † † † † †
MG 3 M166001 0.59 -0.79 .10 † † † †
14 M167001 0.46 2.70 † † † † †
MH 5 M239001 0.97 -1.01 † 0.84 -0.84 † †
9 M236201 0.85 -0.73 .23 † † † †
MI 4 M235301 1.33 0.39 .26 † † † †
11 M236801 1.06 0.09 .23 † † † †
MJ 6 M222901 1.04 -0.36 .05 † † † †
10 M223301 0.42 0.55 † -0.36 0.36 † †
13 M223601 0.99 0.47 .11 † † † †
MK 8 M171101 1.21 0.12 .10 † † † †
11 M162901 0.68 -0.24 † 0.97 -0.97 † †
15 M167901 0.54 1.41 † -1.40 1.40 † †
ML 8 M233801 1.04 1.01 .29 † † † †
11 M231501 0.56 0.17 † † † † †
Last updated 21 May 2017 (DC)
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