Locate Variables

Purpose

Variables and the information about the variables is stored in various types of data and documentation files. You need to know what information is in these files and how to access them to prepare for your analysis. You use this documentation to decide which variables to include in your analysis, identify the variable names and file locations, and consult the data file documentation for detailed data processing and analytic information.

Task 1: Decide which variables to include

Your analysis will require a subset of the variables available in NHANES III. To decide which variables are needed in your analysis, you need to review the survey documentation.

• Key Concepts about Deciding Which NHANES III Variables to Include
• How to Decide Which NHANES III Variables to Include

Task 2: Identify variable names and file locations

Variables are stored in different components. Use the variable list of each component to identify the variable names and file locations.

• Key Concepts about Identifying Variable Names and File Locations
• How to Identify Variable Names and File Locations

Task 3: Consult the documentation

Before analyzing the data, you will need to know how the variable is coded, data editing, processing, and collection information, and the frequency (or sample size) of the variable. This information is found in the documentation.

You cannot determine whether a variable is appropriate to use in your analysis without consulting the data file documentation. Variables may have similar names, be auxiliary, or used for excluding sample persons from certain measures. Read the documentation.

• Key Concepts about Consulting Data File Documentation
• How to Consult the Data File Documentation

NHANES III Tutorial Home

Survey Orientation

Preparing an Analytic Dataset

Survey Design Factors

Additional Resources

National Center for Health Statistics
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For data inquiries, use
nchsquery@cdc.gov

Problems or comments about the Tutorial?
Email the Tutorial Team: NHANESWebTutorial@cdc.gov

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