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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 Physical Science Scale, Grade 8 Science Combined National and State Assessments, By Item and Block: 2011

NAEP Technical DocumentationIRT parameters for Items in the physical science scale, grade 8 science combined national and state  assessments, by item and block: 2011
Block Item NAEP ID aj bj cj dj1 dj2 dj3  dj4  dj5 
† 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 and 2011 Science Assessments.
SC 4 K114001 1.00 0.18 0.31 † † † † †
5 K114002 0.81 0.44 0.20 † † † † †
7 K113201 0.32 -0.73 † 2.54 -1.96 -0.59 † †
10 K113602 (2009) 0.95 2.95 0.40 † † † † †
11 K113603 0.40 0.65 0.07 † † † † †
15 K134201 0.45 -0.08 † -0.28 -0.18 0.46 † †
SD 2 K114601 0.44 0.14 † -0.22 0.42 -0.15 -0.06 †
8 K116701 1.44 1.09 0.31 † † † † †
10 K118901 0.98 -0.70 0.29 † † † † †
11 K122402 0.30 1.75 † -0.67 2.23 -1.57 † †
14 K122001 1.24 0.64 0.26 † † † † †
SE 2 K120601 1.65 1.66 0.29 † † † † †
11 K120901 0.81 0.48 0.21 † † † † †
12 K121401 1.47 0.58 0.51 † † † † †
13 K121402 1.15 0.17 0.37 † † † † †
14 K121403 3.18 1.37 0.11 † † † † †
SF 3 K124601 0.63 1.87 0.30 † † † † †
6 K154901 0.63 0.65 0.25 † † † † †
8 K125001 0.70 1.47 0.28 † † † † †
9 K125002 0.79 0.79 0.27 † † † † †
10 K125003 0.33 0.92 † 0.91 -0.91 † † †
12 K155101 1.26 1.42 0.21 † † † † †
13 K155201 0.87 0.29 0.23 † † † † †
SG 3 K155401 0.64 -0.10 0.15 † † † † †
9 K123901 0.46 0.77 † 1.38 1.77 -0.54 -2.61 †
15 K110801 1.21 1.54 0.26 † † † † †
16 K110101 1.46 1.49 0.34 † † † † †
SH 3 K111901 0.84 1.55 0.45 † † † † †
6 K112401 0.56 1.34 † -0.57 -2.63 3.20 † †
9 K155601 0.26 2.64 † -1.69 1.60 1.82 -1.74 †
10 K117201 0.83 0.48 0.36 † † † † †
11 K117202 0.58 -0.25 † † † † † †
15 K112901 0.72 1.63 0.23 † † † † †
17 K112701 0.50 0.12 0.15 † † † † †
SI 4 K114901 1.37 0.48 0.26 † † † † †
5 K1560CL 0.21 2.20 † 1.16 -0.80 -0.36 † †
10 K115301 1.17 -0.22 0.35 † † † † †
SK 2 K123201 0.72 0.71 0.29 † † † † †
4 K156701 0.70 1.98 0.19 † † † † †
SL 2 K156801 1.23 0.62 0.17 † † † † †
8 K157001 (2009) 0.67 1.01 † 1.30 -1.30 † † †
9 K119505 (2009) 1.05 0.23 † † † † † †
9 K119505 (2011) 0.70 1.12 † 0.69 -0.69 † † †
11 K123401 0.59 0.39 † 0.22 -0.47 0.25 † †
SJ 1 K116401 0.74 -0.58 0.30 † † † † †
9 K110901 0.59 1.67 † 0.07 -0.07 † † †
11 K116001 1.15 1.73 0.26 † † † † †
12 K116002 0.54 0.23 † 0.19 -0.19 † † †
17 K115701 0.65 -0.48 0.25 † † † † †
Last updated 01 July 2014 (GF)
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