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NAEP Technical DocumentationData Codebooks

The data codebook is a printable file containing complete descriptive information for each data field in the corresponding response data file. If the data type is continuous numeric, only one line of descriptive information is printed. If the variable is discrete numeric, the codebook lists the response codes, response-code labels, and frequencies of each value in the data file. The last line under each discrete variable entry contains the "total" or sum of the frequency counts as an extra check for analyses. If an item was used in the generation of scale scores, its scoring key, scale identification, and item response theory (IRT) parameter values are listed to the right of the frequency data. The first column, labeled "SCORE," contains the score value assigned to each response code for use in IRT scoring. The second column, labeled "SCALE," contains a three-character code for the scale on which the item was calibrated. The third column contains the IRT parameter name, with its corresponding value(s) for the sample(s) in which the item was scaled. The following table provides an illustration of an entry in the data codebook file.

2000 National Reading Assessment: Grade  4 Student, Teacher & School Data
 Data codebook for file: R31NT1AT.DAT

   SEQ.   FIELD    REL.            ITEM
    NO.    NAME    IND. TYPE BLOCK  NO.   NAME/DESCRIPTION

   507  R012109     N    OS           9   BOX IN BARN: WHY NOT ANSWER MOM-SHE CALLS     (R1)
        (WO000221)                         VALUE  LABEL                 COUNT  SCORE  SCALE  PARAM     AN       AP
                                              1   Unacceptable            460    0     LIT     A    0.4943   0.5322
                                              2   Acceptable             1355    1             B   -1.4062  -1.2846
                                              5   Illegible                 2                  C    0.0000   0.0000
                                              6   Off Task                  0
                                              7   Non-Rateable              2
                                              8   Omitted                  73
                                              9   Not Reached             249
                                                  Missing                 174
                                                  Total                  2315
                       

Certain blocks of cognitive items in the assessment that are to be used again in later assessments for trend comparisons are designated as nonreleased (e.g., "Rel. Ind.=N"). In order to maintain their confidentiality, generic labels have been substituted for the response category descriptions of these items in the data codebooks and the secondary-use files.

The layout and codebook files for each response data file are combined in a portable document file (PDF) format. This file may be browsed, excerpted and printed using the Adobe Acrobat Reader  program on a variety of platforms and operating systems.

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