<P> For instance, when reporting data from a large city, it might be appropriate to give the average income for black males aged between 50 and 60 . However, doing this for a town that only has two black males in this age group would be a breach of privacy because either of those persons, knowing his own income and the reported average, could determine the other man's income . </P> <P> Typically, census data are processed to obscure such individual information . Some agencies do this by intentionally introducing small statistical errors to prevent the identification of individuals in marginal populations; others swap variables for similar respondents . Whatever measures have been taken to reduce the privacy risk in census data, new technology in the form of better electronic analysis of data poses increasing challenges to the protection of sensitive individual information . This is known as statistical disclosure control . </P> <P> Another possibility is to present survey results by means of statistical models in the form of a multivariate distribution mixture . The statistical information in the form of conditional distributions (histograms) can be derived interactively from the estimated mixture model without any further access to the original database . As the final product does not contain any protected microdata, the model based interactive software can be distributed without any confidentiality concerns . </P> <P> Another method is simply to release no data at all, except very large scale data directly to the central government . Different release strategies between government have led to an international project (IPUMS) to co-ordinate access to microdata and corresponding metadata . Such projects also promote standardising metadata by projects such as SDMX so that best use can be made of the minimal data available . </P>

The 2010 united states census collected data using which approach