What does indirectly identifiable mean?

A respondent may still be identifiable in a file or table through indirect means using additional information. Unique characteristics about a person, place, or company may make the respondent identifiable.

Even if the file or table does not contain identifiable information and only contains aggregate statistics, a knowledgeable person may be able to calculate a respondent's reported value or infer the respondent's identity. The risk of identification may be too high if enough publicly available information is available that a user could estimate information a survey respondent reported. If a number in a table represents the data reported by only two survey respondents, or if the two largest dominate, then one company could subtract its reported value from the published aggregate value and determine the values reported by the other companies in that table cell.