2007 Economic Census

Methodology

Reliability of Data

All data compiled in the economic census are subject to nonsampling errors. Nonsampling errors can be attributed to many sources during the development or execution of the economic census:

• inability to identify all cases in the actual universe;
• definition and classification difficulties;
• differences in the interpretation of questions;
• errors in recording or coding the data obtained and
• other errors of collection, response, coverage, processing and estimation for missing or misreported data.

Selected data from the economic census are subject to sampling errors as well as nonsampling errors. These data are estimated based on information obtained from census report forms mailed to all large employers and to a sample of small employers in the universe. Sampling errors affect these estimates, insofar as they may differ from results that would be obtained from a complete enumeration.

The accuracy of these tabulated data is determined by the joint effects of these sampling and nonsampling errors. No direct measurement of these effects has been obtained except for estimation for missing or misreported data. However, precautionary steps were taken in all phases of the collection, processing, and tabulation of the data in an effort to minimize the effects of nonsampling errors.

When data are presented that reflect both sampling and nonsampling errors, statistical measures of reliability (e.g. a variable for "Percent of sales from administrative records") are provided. The Census Bureau recommends that data users incorporate this information into their analyses, as these errors could impact the conclusions drawn from the data.