About

The tradition

The charge follows the classical and modern advocates of land value tax. Henry George's Progress and Poverty is the case for taking the full rent of land as public revenue. The book is named here, not reprinted.

Classical

• Adam Smith: ground-rent can bear a charge without taxing labour or buildings.
• David Ricardo: a better location yields a surplus.
• Thomas Paine: land rent can fund an equal citizen dividend.
• William Ogilvie: an equal right in the land, and the improver keeps the improvement.
• John Stuart Mill: society has a claim on the unearned rise in land value.
• Henry George: the full rent of land is public revenue.
• The 1909 land campaign associated with Churchill: the British political case.

Modern

• Mason Gaffney: taxes on work end up as a burden on land rent.
• Fred Harrison: speculation inflates the price above economic rent.
• Joseph Stiglitz: public goods capitalise into land value.
• Roger Sandilands: the Scottish case for replacing taxes on earned income.
• Duncan Pickard: charge productive rent after the speculative premium.
• Andy Wightman: the 2010 land-only levy, and the residual method this engine uses.
• Laurie Macfarlane: the housing crisis is largely a land market.
• Martin Adams: collect the land rent and leave wages and buildings untaxed.
• Lars Doucet and the Center for Land Economics: the modern path to a finer assessment.
• The Scottish Land Revenue Group holds this case in Scotland.

The School of Cooperative Individualism is the public library for the classical texts. It is not a second tax.

How a place is calculated

In a town council, the rent for a piece of land is that council's residual rent per square metre times the area of the piece. The residual starts from the average home price, takes off the cost of the building, takes off the speculative part of the price, and then applies a 5% yield. In a rural council the same step uses farmland productive value instead of a house price, and the map colour is one hectare of that farmland. A click shows the piece of land itself.

The Group's homepage illustrates a typical home as about 60% site value, and says prices and rents would fall by at least half. Those claims are not this calculation. The signed-off display flag for that 60% share is off.

The sections below keep the working formulae. They do not change the figure on the map.

Two rent concepts

• Map residual AGR — Wightman residual proxy → Pickard de-speculation → yield. Used for per-square full AGR and as the base that scenarios scale.
• National rent pool (Sandilands) (…/year) — used for equal-share illustration and the income-tax scale factor only.

Integrity & limitations

Caveats load from API config (integrity.caveats) when the backend is online.

Intellectual lineage

Pedagogical layers only — they do not replace residual / de-speculation maths.

Lineage loads from API config when the backend is online.

Next valuation step: sales-based mass appraisal (OpenAVMKit) — see docs/valuation-roadmap.md.

1. Operational — Roger Sandilands (macro)

• True economic rent is approximately … of GDP, not the ~£417m shown in official accounts.
• Gaffney ATCOR: taxes on wages and profits ultimately load onto land rent; Sandilands applies the Scotland income-tax replacement case.
• Replacing Scotland Income Tax could raise … and add ~… GDP growth (zero deadweight loss on pure land rent).

2. Operational — Andy Wightman (valuer residual)

Urban sites use a residual roll assessment:

site_capital_market = MV − DRC(improvements)
site_capital_economic = site_capital_market × Pickard_factor
annual_rent = site_capital_economic × yield

• MV = council HPI average dwelling; DRC = rebuild £/m² × floor area × region × stock remaining factor (default 55%).
• HABU = existing authorised use; hope value excluded from assessment basis.
• Implied land share is an output of residual (not a fixed 60% input). Yield: 5%.
• Rural councils: productive land-use capital × Pickard farmland factor.

3. Operational — Duncan Pickard (de-speculation)

• Urban discount: … of market-implied site value (Harrison: speculative land cycles).
• Farmland discount: … (productive value, not speculative market price).
• Stiglitz: public amenity and infrastructure raise land values — the rent this map measures is largely community-created.
• Macfarlane: most of a home's price is land/location, not construction.

One person's share of the pool

The place card compares this rent with one person's share of the Group's national pool. That is a cash illustration. It is not William Ogilvie's equal right to a share of the soil, and it is not a payment the address receives. The formula is the pool divided by population. It does not change the rent on the parcel.

equal_share_per_person = rent_pool ÷ population
square_share = economic_rent_of_square ÷ equal_share_per_person

• Rent pool: …
• Population: …
• One person's share ≈ …

Per-square formula

1. Snap lat/lng to 3m grid (9 sqm)
2. site_capital_per_sqm = residual_method(council)     [Wightman]
3. despeculated = site_capital × discount_factor         [Pickard]
4. economic_rent = despeculated × yield_rate
5. scenario_charge = policy adjustment (see below)
6. one person's share of the national pool               [illustration]

Policy scenarios

Phase 3 spatial accuracy

• Council areas resolved by boundary polygon (not nearest centroid).
• ROS INSPIRE cadastral parcels queried live via free WMS when available. Map layers also include council multi-metrics (plot AGR, land rent £/m², HPI house prices, AGR as % of price, land share, site capital), SIMD 2020 deprivation shares, population density, rural valuation-method outlines, viewport W3W cell AGR, SVDLS vacant land, and the SG public / Crown Estate overlay (five national bodies; not a title). Coverage, vacant / public / rent-band filters, and verified council planning links sit beside AGR. Open or residual-derived only (no portal scrape, no owners or sale prices on the parcel fabric).
• Glasgow Ward 18 (East Centre) validation case study — toggle on the map or call /validation/glasgow-ward-18.
• What3Words search activates once SLRG nonprofit API key is set.

Economist sign-off

Sign-off status unavailable (API offline).

Charge parameters live in economist_signoff / macro blocks of data/config/agr.yaml. Lineage is pedagogical. Redeploy the API after edits.