rurality-version-by-reference-year

Date: 2026-09-21. Status: implemented.

Decision. The three SPD queries and the walkthrough return the Urban Rural Classification version that suits the year, as rurality_version, rurality_policy, rurality_6fold, rurality_8fold and rurality_status, placed after the shared 41-column core. The version is chosen by reference year, the year it describes, and applies until the year before the next version: 2003-2004, 2005-2006, 2007-2008, 2009-2010, 2011-2012, 2013 to 2015, 2016 to 2019, 2020 to 2021, 2022 onwards. The year is the one that chose the SIMD edition, so an overriding analysis_year fixes both. link_latest.sql uses the latest version throughout. The codes are the matched record's own. rurality_status reports a postcode status where no single record stands for the postcode, then missing_year, before_first_version or invalid_year, then the reason stored with the record. The windows are generated from the registry's reference years. The SSPL set is unchanged.

Reason. PHS publishes no equivalent of Table 4 for rurality, so this is a project choice and is labelled as one in the queries and their output. Reference year rather than publication date because the purpose is to describe where a person lived, not what was knowable when: by publication date, events from 2022 to most of 2024 would take the 2020 version, since the 2022 version appeared on 16 December 2024. A separate status is needed because the SIMD status cannot express these outcomes: 1996 has a SIMD edition and no rurality version.

Evidence. gov.scot: Urban Rural Classification 2022 published 16 December 2024, built on the Census 2022 settlements. Output columns: SSPL 89 unchanged, SPD era and latest 108, SPD as-of 111. tests/test_sql_sets.py states the versions and the year windows independently of the generator and checks fourteen years, the statuses, a large user reporting its own class while its SIMD comes from its link, and that the SSPL set has no rurality column. The walkthrough agrees with the generated query on the four rurality columns across fifteen cases on the built table.