Methodology and sources

Every number on this site comes from the open datasets below. Values for Cholsey parish are often estimates apportioned from smaller or larger areas; each figure's source, geography, method and any estimate flag is shown beside it.

Draft wording: awaiting review by the parish council.

Why some figures are estimates

Public datasets are published for fixed areas such as wards, small neighbourhood areas (called LSOAs) or whole districts. None of them match the Cholsey parish boundary exactly. Where we have to work out a parish figure from another area, we mark it as an estimate and say which area was used.

Home energy (electricity and gas)

The government publishes electricity and gas use for each small neighbourhood area. A neighbourhood area can sit partly inside the parish. For each neighbourhood area we know the total energy used and the number of meters. We add these up across the areas that overlap the parish, counting each area in proportion to how much of it belongs to the parish, then divide total energy by total meters. For Cholsey and Moulsford the share is based on counts of addresses, which is more accurate where homes cluster in one part of an area. For the other parishes it is based on land area. This is why parish energy figures are marked as estimates.

If any of the neighbourhood areas needed for a year is missing from the published data, we leave that year out rather than fill the gap.

Tree canopy cover

Forest Research publishes canopy cover for each ward. We use the ward that contains the parish. Wards are bigger than parishes, so the ward figure is only an estimate of the parish and is marked that way. The England figure only covers the wards in the survey, so it is marked as partial coverage.

Accessible green space

We add up the area of mapped public green space inside each boundary and divide by the number of residents. The map data does not include open countryside or common land, and we leave out allotments, churchyards, cemeteries and golf courses. The result is more likely to be too low than too high.

Solar panels and heat pumps

The Microgeneration Certification Scheme publishes installation counts for the whole district. We use the district's share of homes with an installation as Cholsey's share, so the Cholsey figure is an estimate and cannot show how Cholsey differs from its neighbours. Parish-level counts for neighbouring parishes and for England are not available from this source.

How we compare areas

Each figure is compared with the district and with England using the most recent year available for each. The label reads better, similar or worse, taking into account whether a higher or lower figure is good for that measure. Figures within a small margin of each other count as similar. When the two years differ, the page says so.

Missing data

We never fill gaps by guessing. If a source has no figure for an area or year, the page says that it is not available.

How each figure was produced

Methods and flags used for any area, and the geography used for Cholsey, generated from the data
Metric	Methods used	Flags	Geography used for Cholsey
Tree canopy cover	area weighted	parish estimate, partial coverage	ward E05009737 (Cholsey)
Accessible green space	clip	partial coverage	parish boundary (BFC), clipped
Domestic electricity consumption	address weighted, area weighted, direct	parish estimate	3 LSOAs (address-weighted): E01028619 (100.0%), E01035751 (100.0%), E01035752 (58.3%)
Domestic gas consumption	address weighted, area weighted, direct	parish estimate	3 LSOAs (address-weighted): E01028619 (100.0%), E01035751 (100.0%), E01035752 (58.3%)
Solar PV uptake	direct	parish estimate	South Oxfordshire (E07000179), MCS Data Dashboard
Heat pump uptake	direct	parish estimate	South Oxfordshire (E07000179), MCS Data Dashboard

Metrics

Tree canopy cover (%), higher is better
Accessible green space (m² per resident), higher is better
Domestic electricity consumption (kWh per meter per year), lower is better
Domestic gas consumption (kWh per meter per year), lower is better
Solar PV uptake (% of dwellings), higher is better
Heat pump uptake (% of dwellings), higher is better

Data sources

Sub-national electricity and gas consumption (LSOA/MSOA)

Publisher: DESNZ
Link: https://www.gov.uk/government/statistics/lower-and-middle-super-output-areas-electricity-consumption
Resolution: LSOA/MSOA
Update cadence: annual
Licence: Open Government Licence v3.0
Notes: LSOA figures are domestic-only; MSOA also has non-domestic consumption.

Regional and local authority electricity/gas consumption statistics

Publisher: DESNZ
Link: https://www.gov.uk/government/statistics/regional-and-local-authority-electricity-consumption-statistics
Resolution: local authority / region / country
Update cadence: annual
Licence: Open Government Licence v3.0
Notes: REAL FINDING (P2.5, 2026-09-29): development-plan.md's P2.5 wording ("plus district and national totals from the same release") suggested the LSOA-level file (desnz_lsoa_energy) also carried district/national totals. It doesn't -- those come from this genuinely separate GOV.UK publication (found via the GOV.UK site search API, part of the same "sub-national electricity consumption data" collection, but its own release with its own landing page and its own current-year asset link). Each year's sheet has one row per local authority, plus "All local authorities" rows giving region/country totals (including England, E92000001, and Great Britain) -- both South Oxfordshire (E07000179) and England were verified live: 2023 domestic consumption 272.26 GWh and 83,110.58 GWh respectively. REAL FINDING (P3.4, 2026-09-30): gas's sheet has a genuinely different column layout than electricity's (an extra "Notes" column, no Standard/E7 meter split, header one row lower) -- P2.5 only verified electricity live. Fixed in fetch/desnz_lsoa_energy.py with per-fuel header row/column lookups; 2024 domestic consumption verified live: South Oxfordshire 677.02 GWh, England 242,971.93 GWh (gas).

UK Ward Canopy Cover

Publisher: Forest Research
Link: https://data-forestry.opendata.arcgis.com/datasets/ecba26cfaf9d4b61bddc0e3284348d79_0/about
Resolution: ward
Update cadence: One point per ward, NOT a single "2020" survey as previously assumed (corrected 2026-09-29, P2.3/ADR-0006) -- this is citizen-science i-Tree Canopy data collected ward-by-ward between 2018 and 2022, each ward carrying its own `survyear` field. Cholsey ward's own record was surveyed in 2021.
Licence: Open Government Licence v3.0
Notes: Ward, not parish — needs area-weighted reallocation to Cholsey's parish polygon (spec §4). No cross-year trend for a single ward (plan risk R2) -- each ward has exactly one survey point (Cholsey's: 2021), not a repeatable annual series. REAL FINDING (P2.3/ADR-0006, 2026-09-29): this dataset's "Cholsey" ward record uses wardcode E05009737 (the December 2018 ward edition), NOT E05011701 (the current, Dec 2020 edition confirmed in P1.1/P1.2) -- South Oxfordshire's wards were recoded/redrawn between those vintages. Verified the two boundaries are still a near-exact geometric match for Cholsey specifically (parish is 99.4% within the old ward vs 100.0% within the new one, a difference too small to matter) -- so P1.5's existing ward-weight row (1.0, using E05011701) stands uncorrected, but this was luck, not something the original "working assumption" had actually verified. Q-008 evaluated UKCEH's Land Cover Map as an alternative (ADR-0006): decided to keep this dataset as metric 1's primary source (it measures canopy % directly, matching spec's metric definition) and treat UKCEH LCM as a separate, documented stretch/trend metric instead of conflating two non-equivalent measurements into one.

MCS Data Dashboard / installation data

Publisher: MCS (Microgeneration Certification Scheme)
Link: https://mcscertified.com/low-carbon-landscapes/mcs-data-dashboard/
Resolution: local authority (South Oxfordshire) — the dashboard's own selectable geography filter; no parish-level export found, see ADR-0007's Resolution section
Update cadence: continuously updated on the dashboard; this project's copy is a manual snapshot (2026-09-30), re-pulled by hand when a refresh is wanted — no bulk API
Licence: Confirmed by project lead (Q-013, 2026-10-03): MCS publishes this as open data; fine to use and publish on the public dashboard.
Notes: Covers MCS-certified installs only — undercounts pre-2008 or non-certified installs. Real finding (P2.7, 2026-09-30, ADR-0007): no self-service bulk/postcode download exists on the dashboard — only per-chart CSV exports, filtered to whatever geography the dashboard's own UI offers. Resolved via Q-011 (STATUS.md, answered 2026-09-30): Tom manually retrieved South Oxfordshire's real MCS figures (heat pump and solar PV) via the dashboard's own export, committed as reference data (`fetch/reference_data/mcs_installations/`, see its `_provenance.json` for full retrieval details and two real gaps: no installed-kWp field, and whether a finer-than-LA geography filter exists on the dashboard was not verified). See ADR-0007's Resolution section for the fallbacks originally considered (DESNZ BUS ad-hoc releases, Ofgem FIT) and why this manual MCS retrieval is a better real-data outcome than any of them.

OS Open Greenspace

Publisher: Ordnance Survey
Link: https://www.ordnancesurvey.co.uk/products/os-open-greenspace
Resolution: polygon (site-level)
Update cadence: periodic refresh
Licence: Open Government Licence v3.0
Notes: Free, OGL-licensed. No canopy attribute, only greenspace type — which function types count as "accessible green space" for metric 2 is decided in ADR-0008 (P3.3), not repeated here. Two layers: `greenspace_site` (polygons, what the fetcher reads) and `access_point` (points, not currently used). GB-wide file is clipped to a 500m-buffered bbox around Cholsey + comparators on ingest (read directly out of the downloaded zip via GDAL's zip:// URI, no separate extraction step) so the interim extract stays small, per P2.4.