Supplemental Security Income (SSI) Public-Use Microdata File, 2001 Data
On this page:
- Contact Information
- Background Information
- Content and Sample Design of the SSI Public-Use Microdata File
- Confidentiality Protection
- Available Files
- Accessibility and Usability Information
Contact Information
Comments about what you would like to see on subsequent releases of public-use files based on the Supplemental Security Record (SSR) are welcome. So that future releases can better respond to user needs, please send comments, suggestions, and experiences concerning these files to ssr.microdata@ssa.gov.
Background Information
The SSI program is a means-tested income assistance program for disabled, blind, and aged persons who have limited income and resources. This program is administered in conjunction with the states. Extensive information about the SSI program can be found in the following publications:
- Annual Report of the Supplemental Security Income Program
- Annual Statistical Supplement to the Social Security Bulletin
- Social Security Handbook
- State Assistance Programs for SSI Recipients
- SSI Annual Statistical Report
- Understanding Supplemental Security Income
Content and Sample Design of the SSI Public-Use Microdata File
Information needed to administer the federal SSI program resides on the Supplemental Security Record (SSR) file. In particular, this file contains data used to determine federally administered SSI benefit payments. In December 2001, the SSR contained records for approximately 6.4 million individuals who received a federal SSI benefit for that month. The SSI Public-Use Microdata File drawn from the SSR represents only persons who received a federal SSI payment in December 2001; it excludes persons who received a federally administered state supplementary payment but no federal SSI payment in December 2001.
The SSI Public-Use Microdata File contains an extract of data fields from the SSR and consists of a 5 percent random, representative sample of persons who received a federal SSI payment in December 2001. Records in the underlying SSR for persons who received a federal SSI payment for December 2001 were ordered by state, by disability diagnosis within state, by age within disability diagnosis, and then by sex within age; a 5 percent systematic random sample was then selected. The file contains approximately 320,000 records, with 13 data fields on each record, and is available in a standard SAS file structure.
Since the sample for the SSI Public-Use Microdata File is a representative 5 percent systematic random sample of persons receiving an SSI payment in December 2001, all records have weight equal to 20. Variance and standard errors can be approximated with the standard formulas used for simple random sampling.
Descriptions of data fields are provided in the Data Dictionary for this file. The descriptions cover the content of each field, the method of presentation, and the disclosure avoidance steps taken to provide confidentiality. Because information on the internal SSR record file is used to administer the SSI program, data quality is extremely high because data are validated and kept current. Note that the information on each file refers to a single time period—December 2001.
Confidentiality Protection
Individual identifiers have been removed from all records on this file and other distinguishing characteristics have been modified to prevent identification of persons to whom a record pertains. Records are sequenced in random order.
Topcodes and bottomcodes are employed for all numeric fields to avoid showing extreme field values on a data record. Values beyond the topcode or bottomcode are replaced by the average of the values in excess of the respective topcode or bottomcode. Topcode and bottomcode values were derived at the national level, and the replacement values are derived and applied at the state level for this file (see table). Values shown for categorical fields are groupings of detailed information from the internal file, and numeric variables are rounded to the nearest $5. All topcode and bottomcode values, replacement values, and information on detail groupings are provided to users as part of file documentation.
Available Files
- Data Dictionary and Field Descriptors (PDF)
- Public-Use Microdata File, 2001 Data (ZIP of SAS file—4.1 MB file which unzips to 26.0 MB)
- Table of national topcode and bottomcode values and state replacement values (HTML or PDF)
Accessibility and Usability Information
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