CONFIDENTIALITY CONTROL OF TABULATED DATA - SOME PRACTICAL NETWORK MODELS

The problem of confidentiality control is a significant issue for stat istics gathering organisations. Most existing methods suffer from a va riety of difficulties for practical implementation. This paper present s techniques for confidentiality control of tabulated data using netwo rk formulations to overcome many of the weaknesses of the current meth ods. These techniques are based on the established methodology of cont rolled rounding, which preserves additivity in the resulting solution, while adding a number of pieces of new material. Firstly, a controlle d rounding formulation is introduced that is designed to provide an un biased solution. Then we construct three variations of a controlled pe rturbation technique using different forms of bounds on the cells. Fin ally, a methodology is explained for disturbing only the small-valued cells of the table using each of the four basic methods. A simple exam ple of the methods and results from experimentation on the use of the methods show that they satisfy the needs of confidentiality and are co mputationally viable.