On identification disclosure and prediction disclosure for microdata

Two definitions of statistical disclosure ‐ identification disclosure and prediction disclosure ‐ are compared. Identification disclosure implies prediction disclosure but not vice versa. It is argued, however, that if sampling takes place then cases where prediction disclosure occurs and identification disclosure does not either have very small probability or do not present disclosure problems different from those normally met in the release of aggregate statistics. Finally the estimation of population uniqueness using the Poisson‐Gamma model is considered.