Census and Economic Information Center
1990 CENSUS STF3 AND STF4 DATA LIMITATIONS
Data Limitations
Summary Tape File (STF) 3 & 4
Information provided on Summary Tape File 3 (STF3), Summary Tape File 4 (STF4), and all Subject Summary Tape Files is from the long form questionnaire that was collected from about 1 in 6 housing units. These sample data are subject to sampling error and other limitations.
The 100-percent data are the official counts and should be used as the source of information on items collected on the 100-percent questionnaire such as race, Hispanic origin, age, and number of rooms in housing. These are the counts tabulated from every census questionnaire.
Estimated population and housing unit totals based on tabulations from only the sample questionnaire (sample tabulations) may differ from the official counts.
At smaller geographic levels (e.g. census tract and block group), there will be differences between sample estimates and 100-percent counts for population by race, age, gender, and Hispanic origin and for housing units by tenure, number of rooms, etc. In these cases, users may want to consider using derived measures (mean, median, etc.) or percent distributions.
Whether using absolute numbers or derived measures for small population groups and for a small number of housing units in small geographic areas, users should be cautioned that the sampling error associated with these data may be large.
Last Modified: April 30, 2007
