County Business Patterns continues to apply the Noise Infusion method of data protection that began in 2007. Noise infusion is a method of disclosure avoidance in which values for each establishment are perturbed prior to table creation by applying a random noise multiplier to the magnitude data (i.e., characteristics such as first-quarter payroll, annual payroll, and number of employees) for each company. Disclosure protection is accomplished in a manner that results in a relatively small change in the vast majority of cell values. Each published cell value has an associated noise flag, indicating the relative amount of distortion in the cell value resulting from the perturbation of the data for the contributors to the cell. The flag for ' low noise (G) indicates the cell value was changed by less than 2 percent with the application of noise, and the flag for ' moderate noise (H) indicates the value was changed by 2 percent or more but less than 5 percent. Cells that have been changed by 5 percent or more are suppressed from the published tables. Additionally, other cells in the table may be suppressed for additional protection from disclosure or because the quality of the data does not meet publication standards. Though some of these suppressed cells may be derived by subtraction, the results are not official and may differ substantially from the true estimate.

The number of establishments in a particular tabulation cell is not considered a disclosure; therefore, this information may be released without the addition of protective noise. For an introduction to the noise confidentiality protection method, see Using Noise for Disclosure Limitation of Establishment Tabular Data [PDF] by Timothy Evans, Laura Zayatz, and John Slanta in the Journal of Official Statistics (1998).

Noise infusion was first applied to CBP data in 2007. Prior to 2007, data were protected using the complementary cell suppression method.

Using Noise for Disclosure Limitation of Establishment Tabular Data