Data Swapping

Data swapping, first introduced by Tore Dalenius and Steven Reiss in the late 1970s, is a perturbation method used for statistical disclosure control. The objective of data swapping is to reduce the risk that anyone can identify a respondent and his or her responses to questionnaire items by examining publicly released microdata or tables while preserving the amount of data and its usefulness.

In general, the data swapping approach is implemented by creating pairs of records with similar attributes and then interchanging identifying or sensitive data values among the pairs. For a simplistic example, suppose two survey respondents form a "swapping pair" by having the same age. Suppose income categories are highly identifiable and are swapped to reduce the chance of data disclosure. The first respondent ...