Methodology

Source

HM Land Registry Price Paid Data, downloaded as the published yearly full-year files, covering every recorded residential sale in England and Wales from 1 August 2024 to 31 July 2026. Source dataset. Licensed under the Open Government Licence v3.0.

Contains HM Land Registry data © Crown copyright and database right 2026. This data is licensed under the Open Government Licence v3.0.

Data considered runs to 31 July 2026 — the same date the rest of Your Property Check treats as the newest sale on record, tracked site-wide from one machine-readable file rather than hand-typed per page.

Exact formula

1. Every sale is assigned to its outward postcode district (the part before the space, e.g. “B17” from “B17 8QP”) and to one of two consecutive, non-overlapping 12-month windows by sale date: prior (1 August 2024–31 July 2025) and recent (1 August 2025–31 July 2026).
2. For each outcode and window, take the median sale price — the middle value when every price in that window is sorted (or the average of the two middle values when the count is even). A median, not a mean, so one very high or low sale cannot dominate the figure.
3. % change = (median_recent − median_prior) ÷ median_prior.
4. An outcode is published only if it has at least 10 sales in BOTH windows — see Minimum sample rule below.

Minimum sample rule

Both windows must independently hold at least 10 recorded sales. The rule applies PER WINDOW, not to the combined 24-month total — an outcode with (say) 19 sales in one window and 1 in the other would otherwise pass a combined bar of 20 while its %-change is really driven by a single transaction. The number itself is half of the site's own 24-month outcode indexability threshold (MIN_SALES_24M = 20, lib/seo/gates.ts) applied per window, so any outcode that clears this rule also clears that one. This rule is unit-tested (tests/seo/data-index.test.mjs) — including the exact lopsided case above.

This run: 2,308 outcodes had at least one sale in either window; 2,233 met the rule and are published; 75 were excluded.

Exclusions

• Scotland and Northern Ireland: HM Land Registry Price Paid Data covers England and Wales only. Scottish and Northern Irish outcodes are absent from every window, not excluded by the sample rule.
• Outcodes below the minimum sample in either window (see above).
• No address-level or personal data is published — every row is an outcode-level aggregate.
• No property-type or new-build adjustment is applied — see Limitations.

Limitations

• Mix shift, not just price movement. A simple median reflects what actually sold, not a fixed basket of comparable homes. If an outcode with mostly terraces happens to see more flat sales — or one large new-build completion — in one window, its median can swing sharply even if no individual home's value changed. This is a known limitation of any area-level median (it is why HM Land Registry's own official House Price Index uses a repeat-sales / hedonic regression method, not a raw median) and is not unique to this index.
• Small samples are noisier. An outcode at the minimum sample of 10 is far more exposed to mix shift and single-transaction effects than one with hundreds of sales. Every row states its own sample size (n) precisely so this can be judged per-row rather than assumed.
• No adjustment for inflation, interest rates or regional cost of living — the figures are nominal sold prices, not real-terms.
• PPD is published with a reporting lag; the newest few weeks of any window may under-count sales still being registered.

Changelog

• Issue #1 (31 July 2026 data) — first publication.