Glossary
UK property data, term by term
52 terms you will meet in a MarketCode answer, a tool description or the methodology, defined the way the data uses them and linked to the tool that returns each one.
Identity and geography
- UPRN
- The Unique Property Reference Number: a 12-digit identifier every addressable location in Great Britain carries, and the key MarketCode joins property records on.
- Definition and tools
- Postcode district, area and sector
- The parts of a UK postcode: the area ("SW"), the district ("SW11") and the sector ("SW11 1"); most MarketCode area statistics are published at district grain.
- Definition and tools
- Local authority district (LAD)
- The council area a property sits in: about 360 in Great Britain, the second geography MarketCode publishes indices and rankings for.
- Definition and tools
- GSS code
- The nine-character statistical code the ONS gives every UK administrative area; MarketCode accepts names in most places and bridges them to codes internally.
- Definition and tools
- H3 cell
- A hexagon in the H3 global grid; MarketCode uses resolution-8 cells (about 0.7 km² each) for map density layers and as the spatial unit inside the valuation model.
- Definition and tools
Prices and indices
- Price Paid Data
- HM Land Registry's record of every registered residential sale in England and Wales since 1995: price, date, address, type, tenure and whether it was a standard market sale.
- Definition and tools
- Registration lag
- The weeks to months between a sale completing and HM Land Registry registering it, which makes the most recent months of any sold-price series incomplete.
- Definition and tools
- Repeat-sales index
- A price index built from pairs of sales of the same property, so it measures price change without being pulled by which properties happened to sell; the method behind MarketCode's sold-price and commercial capital indices.
- Definition and tools
- Hedonic index
- A price index that prices the attributes of each property (type, bedrooms, size, location) so that a change in what is on the market does not read as a change in prices; the method behind the asking indices.
- Definition and tools
- Forecast tail
- The points at the end of an index series that fall after the last settled month, projected rather than measured, flagged is_forecast with a lower and upper band.
- Definition and tools
- Price per square metre (£/m²)
- Sale or asking price divided by internal floor area; the one number that makes properties of different sizes comparable, and what the valuation back-series is scaled by.
- Definition and tools
- Market cube
- MarketCode's pre-computed table of price, price per square metre and turnover for every area, asset class, bedroom band and month, with a graded decision on how much evidence sits behind each cell.
- Definition and tools
- Turnover rate
- Sales in a period as a share of the dwellings that could have sold; the liquidity measure, distinct from the raw count of sales, which measures market size.
- Definition and tools
- Transaction volume
- The count of registered sales in an area and period, read straight from HM Land Registry Price Paid rather than from a matched sample.
- Definition and tools
- Rateable value and hereditament
- The VOA's assessment of a non-domestic property's open-market annual rent at a fixed valuation date; the unit assessed is a hereditament, and the assessments form the rating list.
- Definition and tools
Valuation
- Automated valuation model (AVM)
- A statistical model that estimates a property's current value from comparable evidence without an inspection; MarketCode's is trained on registered sales joined to floor area and building form.
- Definition and tools
- Valuation range
- The interval around a valuation estimate that expresses the model's own uncertainty for that property; it widens where evidence is thin.
- Definition and tools
- Trust score
- A score on a full valuation that grades the evidence behind the number: the index sample behind the area, where the floor area came from and the model's own confidence.
- Definition and tools
- Comparable (comp)
- A recent sale or listing of a similar property nearby, used to support or challenge a valuation; MarketCode draws them from the same building and street first.
- Definition and tools
- Floor area
- The internal area of a property in square metres, taken from its energy certificate or measured from building geometry; the input the valuation model cannot do without.
- Definition and tools
- Equity gain (nominal)
- The difference between a property's current estimated value and its last recorded sale price, in pounds and percent, before inflation and without any mortgage.
- Definition and tools
Planning and constraints
- Conservation area
- An area a local planning authority has designated for its special architectural or historic character, where demolition and many external changes need consent.
- Definition and tools
- Listed building
- A building on the National Heritage List for England, protected by grade (I, II* or II); any work affecting its character needs listed building consent.
- Definition and tools
- Article 4 direction
- A direction by a local planning authority withdrawing specified permitted development rights in an area, so work that is normally automatic needs a planning application.
- Definition and tools
- Permitted development
- Changes an owner may make without a planning application, granted nationally by the General Permitted Development Order, subject to limits and to local withdrawal by Article 4.
- Definition and tools
- Green belt
- Land around cities designated to prevent urban sprawl, where new building is inappropriate except in defined circumstances; one of the designations MarketCode checks live.
- Definition and tools
- Brownfield land
- Previously developed land; local authorities keep a register of brownfield sites suitable for housing, which MarketCode reads as a designation.
- Definition and tools
- Flood zone and surface water risk
- The Environment Agency's two flood layers: fluvial and tidal flood zones (1 low, 2 medium, 3 high) and the Risk of Flooding from Surface Water, both returned per property.
- Definition and tools
- Plot utilisation (built coverage)
- The share of a land parcel covered by building footprint; a low figure on a large parcel is the signature of an under-built site.
- Definition and tools
- Mixed-use building
- A building that holds both residential and commercial units; a property of the building's unit mix rather than of any single unit, and the conversion cohort.
- Definition and tools
- House in multiple occupation (HMO)
- A property let to three or more tenants from more than one household who share facilities; licensed by the council above five occupants and often restricted by Article 4.
- Definition and tools
- Council tax band
- The A to H (A to I in Wales) valuation band the Valuation Office Agency assigns every domestic property, based on its value at 1 April 1991 (2003 in Wales); read from the list, never predicted.
- Definition and tools
Ownership
- Title number
- HM Land Registry's identifier for a registered title: a prefix for the office and a number, such as TGL123456; the key ownership records are held against.
- Definition and tools
- Registered proprietor
- The person or entity HM Land Registry records as owning a title; for companies, public bodies and overseas entities MarketCode reads it from the bulk ownership registers.
- Definition and tools
- CCOD and OCOD
- HM Land Registry's two bulk datasets of titles owned by UK companies and public bodies (CCOD) and by overseas companies (OCOD), the source of MarketCode's ownership answers.
- Definition and tools
- Person with significant control (PSC)
- The individual or entity Companies House records as owning or controlling more than 25% of a company; how a corporate proprietor is traced to a person.
- Definition and tools
- Tenure (freehold and leasehold)
- How a property is held: freehold outright, or leasehold for a fixed term under a lease from the freeholder; recorded on every registered sale and every title.
- Definition and tools
Energy
- EPC rating
- The A to G energy efficiency band on an Energy Performance Certificate, lodged when a property is built, sold or let; MarketCode returns the full history of certificates, not just the latest.
- Definition and tools
- Retrofit gap
- The difference between a property's current EPC score and the potential score its certificate says the recommended work would reach.
- Definition and tools
- Minimum energy efficiency standard (MEES)
- The rule that privately rented property in England and Wales must reach at least EPC band E, so F and G stock cannot legally be let without a registered exemption.
- Definition and tools
Market and listings
- Asking price and asking-to-sold ratio
- The price a property is marketed at, as against the price it sells for; asking leads sold by months and includes what never sells, and the ratio between them is a temperature gauge.
- Definition and tools
- Days on market
- How long a listing has been marketed; MarketCode reports the age of live stock and the days to completion on matched sales, and is explicit that a true days-to-sale is not observable from portals.
- Definition and tools
- Listing stock (stock on market)
- The number of properties live on the market in an area on a given day, by channel and bedroom band; a series MarketCode observes forward from September 2026 because it cannot be reconstructed.
- Definition and tools
- Gross yield
- Annual rent as a percentage of price, before costs; net yield deducts costs. MarketCode computes gross yield from listing rents and prices and reports net yield only where an auctioneer quoted one.
- Definition and tools
- Local Housing Allowance (LHA)
- The maximum housing benefit for private tenants, set weekly per bedroom category for each Broad Rental Market Area; the effective rent floor for a benefit-funded tenancy.
- Definition and tools
- Agent market share
- Which estate and letting agents actually list in an area, ranked by listings, with concentration measured by the Herfindahl index and the top-three share.
- Definition and tools
Auctions
- Guide price and hammer price
- The price a lot is marketed at before auction (the guide) and the price it sells for under the hammer (the achieved price); most auctioneers publish the first and few publish the second.
- Definition and tools
- Auction discount
- How far below an automated valuation of the same property an auction lot actually sells; a ratio MarketCode can compute because it holds both the hammer price and the valuation.
- Definition and tools
- Distressed asset
- A property that has gone to auction more than once and never sold; on the public record, a vendor who wants out and a market that has said no.
- Definition and tools
Using MarketCode
- Model Context Protocol (MCP)
- An open protocol that lets an AI assistant discover and call tools on a remote server; MarketCode exposes every data operation as an MCP tool that Claude, ChatGPT, Codex and Cursor can call.
- Definition and tools
- Credit (MarketCode)
- The unit MarketCode meters calls in: most tools are free, licensed and model-run tools cost a fixed number per successful call, and one balance covers MCP, REST and the products.
- Definition and tools
- Read-only tool
- A tool annotated on the server as never changing anything, so an assistant can call it without a confirmation step; every MarketCode tool is read-only.
- Definition and tools
About the glossary
Who is this glossary for?
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Anyone reading a MarketCode answer, a tool description or the methodology page and meeting a term they want defined: analysts, developers writing against the API, and the assistants that call the tools. Each entry links to the tools that return the thing it defines.
Why are the definitions so specific to the data?
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Because the general definition is rarely the useful one. Everyone knows roughly what a house price index is; what matters when you read ours is that it is a repeat-sales index, that thin areas carry the national series, and that the last few months are forecasts. The entries say what the term means here.
Can I suggest a term?
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Yes. Write to [email protected] with the term and where you met it. Terms that appear in tool responses or on the methodology page are added first.
See the terms on a real address.
Thirty minutes on a property or area you choose, every figure named and sourced.