A code with boundaries

An original explanatory article about UK postal geography.

A postcode is familiar enough to be remembered almost without thought. That familiarity makes it a convenient reference when information is collected. Yet a postal reference and an administrative area are not necessarily the same thing.

Royal Mail’s postcode system identifies delivery areas. Some postcodes serve groups of addresses, while large users can have their own. A code should therefore not automatically be treated as a label for one individual home.

For statistics, postcodes can be linked with other geographical units, such as electoral wards. The difficulty is that their boundaries do not always coincide. Placing a whole postcode in one ward can leave some addresses on the other side of the ward boundary.

Postal geography is useful, but interpreting it requires attention to what the code actually represents.

What does the article explain about the usefulness and limitations of postcodes as geographical references?