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Merging Files

Prior to merging, a reorganization of the files is performed and includes the following tasks:

  1. Files are separated by subject area to improve maintenance and efficiency.
  2. The files are restructured, eliminating unused (blank) areas to reduce the size of the files.
  3. In cases where students chose not to respond to an item, the missing responses are recoded as either "omit" or "not reached."
  4. A school file is created by merging the school characteristics and policies questionnaire file and can be associated with a student record in order to report school information for students.

Following the reorganization of data files, the following merging steps take place:

  1. Final student reporting weights data are merged with the student-weight files.
  2. The resulting file is then merged with the students with disabilities/limited-English-proficient (SD/LEP) student questionnaire and teacher questionnaire data.

The matching criteria used in these steps are:

  • In all steps, the 10-digit booklet identification number is used as the matching criterion. The first three numbers correspond to the 3-digit booklet number common to every booklet with the same blocks of items (see an example of a common booklet number—201—in the Grade 4 NAEP 2000 Science Assessment.) The next six digits correspond to the 6-digit serial number unique to the booklet a student is given, and the last number is a single-digit check.

  • The teacher data can be linked to the student data through four data variables: the Federal Information Processing Standards (FIPS) code, school code, teacher number within school, and classroom period. Prior to 2002, when NAEP used separate national and state samples, the teacher data could be linked to the student data through four data variables: primary sampling unit (PSU) school code, teacher number within school, and classroom period.

  • As with teacher data, school data can be linked to the student data through the FIPS or PSU codes and a sequential school code. Since 2002, the FIPS code has been the matching criterion used for all school data.  Prior to 2002, the PSU and school codes were used as the matching criterion for the national school data, and the FIPS code was used for state school data. Since some schools did not return a questionnaire, some of the records in the school file contained only school-identifying information.

  • Whenever new data values (such as composite background variables or plausible values) are derived, they are added to the appropriate database files using the same matching procedures described above.

School and student names are kept secure and are not included in the matched data files.


Last updated 03 February 2010 (GF)

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National Center for Education Statistics - http://nces.ed.gov
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