Data zones are the key geography for the dissemination of small area statistics in Scotland and are widely used across the public and private sector. Composed of aggregates of Census Output Areas, data zones are large enough that statistics can be presented accurately without fear of disclosure and yet small enough that they can be used to represent communities. They are designed to have roughly standard populations of 500 to 1,000 household residents, nest within Local Authorities (at the time of the Census), have compact shapes that respect physical boundaries where possible, and to contain households with similar social characteristics. Data zones also represent a relatively stable geography that can be used to analyse change over time, with changes only occurring after a Census. Data Zone boundaries were first created following the 2001 Census, with 6,505 data zones covering the whole of Scotland. Centroids were also calculated from a population weighted sum of Census Output Area centroids that fall within a data zone. These centroids are used to link data zones to other (higher level) geographies and produce a 'best-fit' match. Aggregations of data zones are often used to approximate a larger area of interest or a higher level geography that statistics wouldn’t normally be available for.