  We propose a two-phase synthesis process for synthesizing income, a sensitive
variable which is usually highly-skewed and has a number of reported zeros. We
consider two forms of a continuous income variable: a binary form, which is
modeled and synthesized in phase 1; and a non-negative continuous form, which
is modeled and synthesized in phase 2. Bayesian synthesis models are proposed
for the two-phase synthesis process, and other synthesis models are readily
implementable. We demonstrate our methods with applications to a sample from
the National Health Interview Survey (NHIS). Utility and risk profiles of
generated synthetic datasets are evaluated and compared to results from a
single-phase synthesis process.
