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NAEP Analysis and Scaling → Estimation of NAEP Score Scales → NAEP Assessment IRT Parameters → Science Assessment IRT Parameters → IRT Parameters for Items in the Earth and Space Science Scale, Grade 12 Science National Main Assessment, by Item and Block: 2009

NAEP Technical DocumentationIRT parameters for items in the earth and space science scale, grade 12 science national main assessment, by item and block: 2009
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), 2009 Science Assessment.
S3 4 K133301 0.41 2.12 † -0.54 0.54 † †
5 K1572CL 0.29 1.29 † 1.61 2.63 -4.24 †
S4 2 K128001 0.21 -1.82 0.31 † † † †
10 K157701 1.17 1.89 0.27 † † † †
11 K157801 0.87 0.47 0.23 † † † †
12 K157901 0.86 -0.00 † † † † †
18 K130201 1.04 0.99 0.31 † † † †
S5 4 K143901 0.76 0.22 0.30 † † † †
5 K143902 1.79 2.05 0.19 † † † †
6 K143903 0.62 1.75 † 0.54 -0.54 † †
10 K130301 0.82 -0.82 † † † † †
S6 2 K135001 0.83 1.87 † 0.20 -0.14 -0.07 †
3 K134701 0.84 1.45 0.33 † † † †
5 K130901 0.23 1.04 0.31 † † † †
11 K140501 0.66 0.95 0.29 † † † †
12 K143201 0.92 -0.35 0.24 † † † †
17 K130701 1.36 1.36 0.25 † † † †
S7 3 K131401 0.59 0.39 0.26 † † † †
7 K131901 0.97 1.58 0.17 † † † †
13 K141901 1.43 0.64 0.29 † † † †
14 K158301 0.77 1.34 † 0.47 -0.47 † †
16 K132101 1.28 0.00 0.20 † † † †
S8 2 K140801 1.28 0.75 0.21 † † † †
9 K142401 0.64 0.21 † 0.27 -0.27 † †
12 K137601 0.28 0.22 † -1.04 0.08 0.96 †
13 K137602 1.81 1.55 0.38 † † † †
16 K137001 0.89 0.98 0.24 † † † †
S9 3 K126701 0.39 1.42 0.27 † † † †
8 K139701 1.58 0.30 0.13 † † † †
9 K139702 1.33 0.12 0.25 † † † †
12 K139101 0.61 1.00 † -0.35 0.35 † †
17 K131601 0.53 -0.44 0.27 † † † †
18 K128101 1.46 0.43 0.32 † † † †
S10 9 K1586CL 0.74 1.65 † 2.25 0.66 -1.50 -1.42
13 K129801 0.68 2.45 0.36 † † † †
15 K140901 1.68 0.50 0.29 † † † †
S11 2 K139301 0.86 -0.06 0.29 † † † †
9 K125802 0.95 1.62 † 0.47 -0.47 † †
10 K125803 0.71 1.42 † -0.63 0.63 † †
15 K141801 1.00 2.17 0.28 † † † †
S12 2 K133001 0.57 2.04 0.24 † † † †
5 K128701 0.34 1.11 † 0.47 0.46 -1.45 0.52
15 K142101 0.72 0.55 0.28 † † † †
S13 2 K129501 0.80 2.16 0.47 † † † †
4 K126001 0.62 1.33 † 0.31 0.13 0.04 -0.48
13 K144601 0.87 0.75 0.23 † † † †
Last updated 03 June 2016 (GF)
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