Sources and limitations
Every number in the explorer is copied from a downloaded official file under the
Open Government Licence v3.0
(or cited academic/secondary work in the fiscal panel). Nothing is interpolated to fill a gap.
Years and places without a comparable published series are marked
no comparable data and the map is dimmed.
What this Phase 4 build can and cannot show
- The map has three official geography levels: UK nations (Natural Earth), ITL1 regions (ONS Open Geography January 2021 BUC), and local authority districts (ONS Open Geography December 2021 BUC). A year or layer without a published figure at the selected level is dimmed and labelled no comparable data.
- Country of birth, nationality, and ethnic group are separate layers, plus a side-by-side compare view. None of them is labelled “native”. Census national identity (Scotland Figure 9 / NISRA MS-B15) is listed separately — it is not citizenship.
- The view is shareable:
?layer=&year=&year2=&geo=&metric= restores layer, year, optional comparison year, geography (level or area code), and series.
- Scotland Census 2022 (EILR chart data) and NISRA Census 2021 main-statistics tables are ingested where they align with existing country-of-birth, ethnicity, religion, and nationality stocks. Categories are not remapped onto England & Wales headings — see the concordance notes.
- Ethnicity cannot be mapped before 1991. This extract has E&W 2011 and 2021 high-level groups, Scotland 2011 and 2022 headings, and NISRA MS-B01 2021. Those White percentages are three different published categories.
- Modern religion affiliation cannot be mapped before 2001. This extract has E&W 2011/2021, Scotland 2011/2022, and NISRA MS-B19 2021. MS-B23 (religion brought up in) is not mixed into affiliation maps. NISRA has no standalone Muslim column.
- Scotland council-area census stocks (UV201 / UV204 / UV205) were not retrieved as a stable bulk file — those LAs stay no comparable data except 2024 births (NRS Table 3.09).
- Age–sex pyramids: mid-2025 E&W and mid-2024 UK nations (ONS MYE2). Country-of-birth-by-age tables are census snapshots (Scotland Figure 8; NISRA MS-A31; RM011 if downloaded). They are not MYE pyramids.
- Births by mother’s country of birth are three vital-registration systems (ONS E&W, NRS, NISRA), not one UK line. The E&W regional 2016–22 figure is either parent born outside the UK.
- Long-term migration flows are a UK series. IPS-era (1964–2015) and admin-based LTIM (2012–, YE December) are drawn separately and must not be read as one line.
- Asylum and detection summaries include year-ending June 2026 points where the Home Office tables publish them. Small-boat and illegal-entry figures are detections. They are not a count of people in the UK without permission.
- The fiscal panel is an assumptions filter over cited MAC / OBR / Migration Observatory / Dustmann–Frattini figures. It is not a map of “the cost of immigration” and it never averages studies into one number.
Inventory: docs/inventory.md. File list: data/SOURCES.md.