Estimation of a measure of disclosure risk for survey microdata under unequal probability sampling

Skinner and Elliot (2002) proposed a simple measure of disclosure risk for survey microdata and showed how to estimate this measure under sampling with equal probabilities. In this paper we show how their results on point estimation and variance estimation may be extended to handle unequal probability sampling. Our approach assumes a Poisson sampling design. Comments are made about the possible impact of departures from this assumption.