Data methodology
This page explains where House Price Watch data comes from, how it is processed, and what the figures mean.
What data source is used?
House Price Watch uses HM Land Registry price paid data for England and Wales. Boundary and map context is based on OpenStreetMap. Postcode centroid coordinates are sourced from the Office for National Statistics (ONS).
How are prices calculated?
Prices are calculated from recorded HM Land Registry sale transactions at postcode level, then aggregated to the selected location. We use these records to calculate average prices by month and year, identify the most expensive homes sold in each location, and generate additional summary statistics shown across the site. All figures reflect completed sales, not asking prices or valuations.
How is the data pipeline built?
The process is: (1) postcode centroids from ONS are matched and grouped into locations defined by OpenStreetMap boundaries and hierarchy; (2) HM Land Registry sale records for those postcodes are joined in; (3) location-level outputs are generated, including average prices, properties sold, top sales, property type mix, and price-range distributions.
What does the location hierarchy mean?
Location pages are nested. For example, UK data rolls down into regions and then smaller local areas. Rankings, charts, and summaries are generated using the selected level in that hierarchy. The location hierarchy and boundaries are sourced from OpenStreetMap (Open Street Map).
How often is data updated?
Each page includes a "Last updated" timestamp and the latest data coverage month. This indicates when the local dataset was last refreshed and up to which period Land Registry data has been included. Land Registry data is updated monthly, but it is usually delayed by about one month.
What should this data be used for?
Use this data to understand long-term market trends, price ranges, and relative differences between locations. It should not be treated as a current valuation of an individual property.