Case Study: Office for National Statistics creates privacy-protected, comparable census output areas with Ordnance Survey

Office for National Statistics - Customer Case Study

The Office for National Statistics (ONS) needed a way to publish detailed 2001 and 2011 census estimates without revealing information about individuals, households or businesses. Working under the Public Sector Mapping Agreement (PSMA), ONS used Ordnance Survey data — including ADDRESS-POINT, Boundary-Line and OS MasterMap ITN — to create stable small-area geographies (output areas) that balance statistical detail with privacy protection.

Ordnance Survey supplied the spatial datasets and licensing that enabled ONS to build about 175,000 output areas (averaging ~300 people or 125 households each, with minimum thresholds of 100 people/40 households), group them into super output areas, and adjust just 2.6% for 2011 to reflect population change. The result, delivered using Ordnance Survey data, preserved confidentiality, ensured comparability between 2001 and 2011 statistics, improved spatial analysis usability, and added workplace zones to support research into where people work as well as live.

Office for National Statistics

Andy Tait

Head of ONS Geography