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6.2. Tobacco Related Codebooks This section provides general and detailed information for data analysts who need to understand the changes to the tobacco related codebooks over the years. See Section 6.2.2 for a list of codebook files. See Section 6.2.3 for the web links. 6.2.1 Overview of the NHIS Tobacco Codebook Files In order to analyze data on tobacco use, the analyst needs to consult the NHIS codebooks for the desired years to determined which variables to use in the analysis. The NHIS codebook format has undergone major changes over the years, so the essential information is provided here to help the analyst. NHIS codebooks are abbreviated documents that present condensed information from the questionnaire and the dataset to assist the analyst in selecting variables and writing computer programs to analyze data using standard statistical packages such as SAS, SPSS, SUDAAN, or STATA. Synonyms for codebook used in the NHIS documentation include: file layout, tape layout, and data dictionary. Note that there is not always a one-to-one relationship between a question in the questionnaire and a variable in the public use dataset. For some questions, there are several variables, either because more than one answer can be selected, or because recodes were computed. Alternatively, a given recode may be a composite of several variables. For some questions, the answers are not released in the NHIS public use dataset to protect confidentiality, but recoded information can be released. There can be multiple files for each NHIS data year and there is a corresponding codebook for each data file. Generally, a NHIS codebook contains the following components:
Major Changes to the NHIS Codebook Format: 1965-1996: The NHIS codebooks from these years included: sample size, frequencies, column numbers, variable labels, answer codes, and value labels. These codebooks did not usually include variable names. 1997-2003: With the advent of the 1997 questionnaire redesign, variable names were systematically created for each variable, and included for every variable in each codebook. 2004 to present: Beginning with the 2004 data year NHIS codebook information can be found in the following files:
This page last reviewed October 15, 2008
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