Effects of Rounding on the Quality and Confidentiality of Statistical Data

Abstract

Statistical data may be rounded to integer values for statistical disclosure limitation. The principal issues in evaluating a disclosure limitation method are: (1) Is the method effective for limiting disclosure? and (2) Are the effects of the method on data quality acceptable? We examine the first question in terms of the posterior probability distribution of original data given rounded data and the second by computing expected increase in total mean square error and expected difference between pre- and post-rounding distributions, as measured by a conditional chi-square statistic, for four rounding methods.