Output Area (OA)

Definition

An Output Area (OA) is the smallest geographic unit used for Census data collection in England, Wales, Scotland and Northern Ireland. Designed to be socially homogeneous, OAs typically contain 40-250 households or 100-625 residents. There are some exceptions where OAs may have more than 625 people, for example, where there is a large prison.

Also known as

Census Output Area

Relevance to OCSI

OAs are the smallest geographical unit used in OCSI’s Local Insight tool. However, for the purposes of protecting the confidentiality of data subjects, including individuals, households, and corporate bodies, statistical disclosure methods are often applied to OA data. This means OCSI will often utilise data aggregated into LSOAs or MSOAs as they can be more useful for identifying insights.

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