Improvement of the Sampling Methods in Official Statistics and Assessment of the Disclosure Risk of Microdata Sets

点击翻译按钮获取中文摘要

Our aim was to assess the disclosure risk of microdata and to improve the sampling methods of the official statistics.The observed sample size indexes and the estimated population size indexes are often used to assess the disclosure risk of microdata which is sampled from a population. In estimation of population size indexes based on sample size indexes, the parametric method with a superpopulation model is the mainstream today. We proposed a nonparametric maximum likelihood estimation method in which some simple restrictions for population size indexes were used, and tried to adopt the generalized Zipf's model for the restriction. The estimation method using information of subpopulations was also investigated Simultaneously with the risk assessment of microdata, some problems for the tabular data and usefulness of the. masked microdata were studied.We were permitted to use three official statistics, Labour Force Survey, Family Income and Expenditure Survey and National Survey of Family Income and Expenditure, and then we could present the form of the safe microdata set for each statistics. In examination for Labour Force Survey the time series were taken into consideration, and we used not only attributes of households but also those of individuals for other two statistics.We held one symposium and several workshops every year in alliance with other research groups to exchange ideas with the researchers in various fields. We planed the special issue "Statistical Theory for Disclosure of Microdata" in Proceedings of the Institute of Statistical Mathematics, in which our articles were contained. Our research results were also presented in various journals.