Examples of Easy-to-implement, Widely Used Methods of Masking for which Analytic Properties are not Justified

This paper provides examples that illustrate the severe analytic distortions of many widely used masking methods that have been in use for a number of years. The masking methods are intended to reduce or eliminate re-identification risk in public-use files. Although the masking methods yield files that do not allow reproduction of the analytic properties of original, confidential files, in a number of situations they sometimes allow small amounts of re-identification using elementary methods and widely available software.