simd-domain-bands

Date: 2026-09-30. Status: implemented.

Decision. Both tables carry the Scottish Government's published quintile, decile and vigintile of every domain rank, for every edition, simd_domain, copied from three statistics.gov.scot datasets (2004 to 2012, 2016, 2020) and never derived, as for every band (bands-are-looked-up). The ranks stay from the shapefiles. A band is admitted only where its dataset's rank is the shapefile's: equal, or a half rank the 2004 to 2012 dataset rounds up, or one of the 628 2020v2 housing zones pinned with both ranks in simd_ingest/sgs_2020_housing_rank_disagreements.csv; anything else stops the build. Those 628 zones carry simd2020v2_housing_domain_rank_source_status = rank_sources_disagree: the two Government publications disagree on the rank; it is not a statement that the band is wrong. 123 band columns and the status, appended after every existing column: schemas postcode_simd_wide_v4 (354) and postcode_simd_sspl_v4 (311). The SQL core grows from 48 to 70 columns and never counts the status as missing; Python returns the answering record's status for housing, and split parts reach consensus only if they agree on both the value and the status. Unweighted and Scotland only. Released as 5.0.0.

Reason. The Government publishes domain bands for every edition, so a derived band would be a second, competing version: no rule on the rank alone reproduces all of them, since the publisher splits some ties across adjacent bands and placed the same 2016 and 2020 tie differently. Copying keeps the publisher's value, and checking the ranks keeps each band tied to the ranking we carry. The SIMD team has been asked which 2020 housing ranking is authoritative; the feature does not wait for the answer.

Evidence. The vintage band rules reproduce all 18 published overall series and PHS's weighted Scotland bands for all six editions, but against the 819,897 published domain bands the best rank-only rule disagrees in 19. Split ties: 2006 income and employment, 2009 employment (S01001951 and S01006050, both 1952, deciles 3 and 4). The 2790.5 housing pair S01008149 and S01012978 is decile 5 in 2016 and 4 in 2020. 2020 housing ranks differ in 628 zones by 0.5 to 4.5 places, S01008634 2093 against 2092.5; under the 2020 convention that changes a band in two zones only. The overall index agrees in both publications for every edition and zone. The datasets are byte-identical across downloads. The 230 history and 187 main columns of 4.0.0 keep their fingerprints. Plans: docs/plans/Domain_Ntiles_Test_Plan.md and docs/plans/Domain_Bands_Plan.md. Answered 2 October 2026 by the Scottish Government's SIMD team (email to Michele Tinti): the SIMD 2020v2 ranks workbook is the definitive version, the differences are too small to worry about, and are probably due to how ties were treated. The ranks we carry equal the workbook in every zone, so the status marks zones where statistics.gov.scot departs from the definitive ranking. Our check of the explanation: 115 of the 628 zones are tied in neither ranking, and the largest tied group among them has six zones, which cannot account for a 4.5-place difference, so ties explain only part; the effect remains two band changes, no quintile. No change to the build.

Columns (124): simd2004_access_domain_decile, simd2004_access_domain_quintile, simd2004_access_domain_vigintile, simd2004_education_domain_decile, simd2004_education_domain_quintile, simd2004_education_domain_vigintile, simd2004_employment_domain_decile, simd2004_employment_domain_quintile, simd2004_employment_domain_vigintile, simd2004_health_domain_decile, simd2004_health_domain_quintile, simd2004_health_domain_vigintile, simd2004_housing_domain_decile, simd2004_housing_domain_quintile, simd2004_housing_domain_vigintile, simd2004_income_domain_decile, simd2004_income_domain_quintile, simd2004_income_domain_vigintile, simd2006_access_domain_decile, simd2006_access_domain_quintile, simd2006_access_domain_vigintile, simd2006_crime_domain_decile, simd2006_crime_domain_quintile, simd2006_crime_domain_vigintile, simd2006_education_domain_decile, simd2006_education_domain_quintile, simd2006_education_domain_vigintile, simd2006_employment_domain_decile, simd2006_employment_domain_quintile, simd2006_employment_domain_vigintile, simd2006_health_domain_decile, simd2006_health_domain_quintile, simd2006_health_domain_vigintile, simd2006_housing_domain_decile, simd2006_housing_domain_quintile, simd2006_housing_domain_vigintile, simd2006_income_domain_decile, simd2006_income_domain_quintile, simd2006_income_domain_vigintile, simd2009v2_access_domain_decile, simd2009v2_access_domain_quintile, simd2009v2_access_domain_vigintile, simd2009v2_crime_domain_decile, simd2009v2_crime_domain_quintile, simd2009v2_crime_domain_vigintile, simd2009v2_education_domain_decile, simd2009v2_education_domain_quintile, simd2009v2_education_domain_vigintile, simd2009v2_employment_domain_decile, simd2009v2_employment_domain_quintile, simd2009v2_employment_domain_vigintile, simd2009v2_health_domain_decile, simd2009v2_health_domain_quintile, simd2009v2_health_domain_vigintile, simd2009v2_housing_domain_decile, simd2009v2_housing_domain_quintile, simd2009v2_housing_domain_vigintile, simd2009v2_income_domain_decile, simd2009v2_income_domain_quintile, simd2009v2_income_domain_vigintile, simd2012_access_domain_decile, simd2012_access_domain_quintile, simd2012_access_domain_vigintile, simd2012_crime_domain_decile, simd2012_crime_domain_quintile, simd2012_crime_domain_vigintile, simd2012_education_domain_decile, simd2012_education_domain_quintile, simd2012_education_domain_vigintile, simd2012_employment_domain_decile, simd2012_employment_domain_quintile, simd2012_employment_domain_vigintile, simd2012_health_domain_decile, simd2012_health_domain_quintile, simd2012_health_domain_vigintile, simd2012_housing_domain_decile, simd2012_housing_domain_quintile, simd2012_housing_domain_vigintile, simd2012_income_domain_decile, simd2012_income_domain_quintile, simd2012_income_domain_vigintile, simd2016_access_domain_decile, simd2016_access_domain_quintile, simd2016_access_domain_vigintile, simd2016_crime_domain_decile, simd2016_crime_domain_quintile, simd2016_crime_domain_vigintile, simd2016_education_domain_decile, simd2016_education_domain_quintile, simd2016_education_domain_vigintile, simd2016_employment_domain_decile, simd2016_employment_domain_quintile, simd2016_employment_domain_vigintile, simd2016_health_domain_decile, simd2016_health_domain_quintile, simd2016_health_domain_vigintile, simd2016_housing_domain_decile, simd2016_housing_domain_quintile, simd2016_housing_domain_vigintile, simd2016_income_domain_decile, simd2016_income_domain_quintile, simd2016_income_domain_vigintile, simd2020v2_access_domain_decile, simd2020v2_access_domain_quintile, simd2020v2_access_domain_vigintile, simd2020v2_crime_domain_decile, simd2020v2_crime_domain_quintile, simd2020v2_crime_domain_vigintile, simd2020v2_education_domain_decile, simd2020v2_education_domain_quintile, simd2020v2_education_domain_vigintile, simd2020v2_employment_domain_decile, simd2020v2_employment_domain_quintile, simd2020v2_employment_domain_vigintile, simd2020v2_health_domain_decile, simd2020v2_health_domain_quintile, simd2020v2_health_domain_vigintile, simd2020v2_housing_domain_decile, simd2020v2_housing_domain_quintile, simd2020v2_housing_domain_rank_source_status, simd2020v2_housing_domain_vigintile, simd2020v2_income_domain_decile, simd2020v2_income_domain_quintile, simd2020v2_income_domain_vigintile