Microdatadisclosurelimitationin Statistical Databases: Quev Size and Random Sample Qwy Control

A probabilistic framework can be employed to assess the n“skof disclosure of confidential information in statistical databases that use disclosure control mechanisms. We illustrate how the method may be used to assess the strengths and weaknesses of two tm”stingdisclosure control mechanisms quey set size res&”ctioncontrol and random sample query control mechanisms. Our results indicate that neither scheme provides adequate security. i’%e framework is then jiuther exploited to analyze an alternative scheme combining query set size restriction and random sample que?ycontrol. We show that this combination results in a sig~ificant decrease in the n“skof disclosure.