Differentially Private Hierarchical Group Size Estimation.

Consider the problem of estimating, for every integer j, the number of households with j people in them, while protecting the privacy of individuals. Add in a geographical component, so that the household size distribution can be compared at the national, state, and county levels. This is an instance of the private hierarchical group size estimation problem, in which each group is associated with a size and a hierarchical attribute. In this paper, we introduce this problem, along with appropriate error metrics and propose a differentially private solution that generates group size estimates that are consistent across all levels of the hierarchy.