  We report on our experiences of helping staff of the Scottish Longitudinal
Study to create synthetic extracts that can be released to users. In
particular, we focus on how the synthesis process can be tailored to produce
synthetic extracts that will provide users with similar results to those that
would be obtained from the original data. We make recommendations for synthesis
methods and illustrate how the staff creating synthetic extracts can evaluate
their utility at the time they are being produced. We discuss measures of
utility for synthetic data and show that one tabular utility measure is exactly
equivalent to a measure calculated from a propensity score. The methods are
illustrated by using the R package $synthpop$ to create synthetic versions of
data from the 1901 Census of Scotland.
