To conduct analyses using NHANES I data, an analyst will typically include selected variables from at least two data files. Therefore, you will need to keep and merge data to create your analytic dataset to include variables from different data files.
NHANES I data files were released by their collection method or component. Many of these are very large data files with many variables. Most analysts will only need a few selected variables. You will likely wish to keep only those variables when you create your analytic dataset. This process uses a SAS option statement called keep.
- Key Concepts about Keeping Data in NHANES I
- How to Keep NHANES I Data
- Download Sample Code and Dataset
The NHANES I data files were organized primarily by 20 different topic areas. It is very likely that variables of interest to you come from different data components (topic areas). Joining the components of the data files is called merging.
When choosing which files to merge, be aware that some of these files only contain data on the detailed subsample or the augmented population.