What format are the data in?
IPUMS produces fixed-column ASCII data, CSV files, or SPSS, SAS, or Stata formatted data. Users can select the data format they prefer within the data extract system.
Data are entirely numeric. By default, the extraction system rectangularizes the data: that is, it puts household information on the person records and does not retain the households as separate records. No information is lost, and this is the format preferred by most researchers; however, the extraction system includes the option of hierarchical data or household record only data.
The system generates SPSS, SAS and Stata syntax files with which to read in the ASCII data. In addition, users can select the data format for their extract on the extract request page of the IPUMS projects, NAPP and IHIS. This allows users to download CSV, SPSS, SAS, and State data files directly.
A codebook file is also created with each extract. It records the characteristics of your extract and should be downloaded for record-keeping.
All data files are created in gzip compressed format. You must decompress the file to analyze it. We recommend using 7-zip to do so.