Variables and the information about the variables are 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. Use this documentation to decide which variables to include in your analysis, identify the file locations and variable names, and consult the data file documentation for detailed data processing and analytic information.
Your analysis will require a subset of the variables available in NHANES II. To decide which variables are needed in your analysis, you need to review the survey documentation.
- Key Concepts about the Deciding Which NHANES II Variables to Include
- How to Decide Which NHANES II Variables to Include
Task 2: Identify Variable Names and File Locations
After using the Plan and Operation Report description of components and detailed appendix of data collection forms and questionnaires to identify the particular questions, measurements, or other information to include in your analysis, you must determine where the data are found since variables are stored in different files. This can be done by comparing the name of the data collection form in the Plan and Operation report with the data file names listed on the NHANES II webpage.
- Key Concepts about Identifying Variable Names and File Location
- How to Identify File Locations and Variables Names
Task 3: Consult NHANES II Documentation
Before analyzing the data, you will need to learn how the variable is coded, the frequency (or sample size) of the variable, and any special notes provided for analysis. This information is also found in the tape documentation PDF file.
- Key Concepts about Consulting NHANES II Data File Documentation
- How to Consult the NHANES II Data File 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.