Methodology
How the Hauscope Index is built
The Index measures the Asking Gap: how far asking prices sit from Hauscope’s evidence-based estimate of fair value. This page sets out where the numbers come from, the rules applied, what the Index cannot tell you, and who pays us — so you can judge the figures rather than take them on trust. Back to the Index →
1. What the Asking Gap is
For each property a buyer checks, we record two figures at that moment: the asking price as listed, and Hauscope’s evidence-based estimate of fair value. The gap between them, expressed as a percentage of the estimate, is that property’s Asking Gap. A positive gap means the asking price sits above what the evidence supports; a negative gap means it sits below.
The Index reports the median gap per postcode area, not the mean. A median is unmoved by a handful of extreme listings, which matters in a dataset where the extremes reflect estimate uncertainty as much as seller behaviour.
2. Where the data comes from
Every figure comes from Hauscope’s own report history. When a buyer runs a report, we freeze the asking price and the estimate as they were at that moment. The Index reads those frozen records — it never re-runs old properties through today’s model. An edition therefore stays true to the market it measured, and a past edition cannot be quietly improved after publication.
The estimate itself is built from HM Land Registry Price Paid data, local sold-price history, and EPC floor-area records. The valuation method is documented separately.
3. The rules
| Rule | Setting | Why |
|---|---|---|
| Window | 90 days | Captures the most areas above the sample floor. A 120-day window adds none. |
| One per property | latest check | A home checked five times is one data point, not five, so popular listings can’t weight an area. |
| Outlier cap | ±50% | Gaps beyond this cluster in areas with too few comparable sales for a reliable estimate. Removing them moves the national median by about 0.3 percentage points, so the headline does not depend on this choice. |
| Sample floor | n ≥ 30 | Below this, a single unusual listing moves the area’s median. |
| Geography | England & Wales | We hold no Scottish or Northern Irish sold-price data, so estimates there rest on absent comparables. See §5. |
The Index is rebuilt automatically on the 1st of each month under exactly these rules. Each edition stores the settings it was computed under, so an old figure can always be read back with the rules that produced it.
4. The biggest caveat: whose homes these are
These are properties real buyers chose to check on Hauscope. They are not a random sample of the market, and nothing here should be read as though they were.
Buyers plausibly lean towards listings they already suspected were priced high — wanting something to negotiate with. If so, overpriced homes are over-represented and the measured gap is too high, not too low. The honest reading is that the true whole-market gap is probably smaller than the Index shows. We would rather state that plainly than let the number carry more weight than it can bear.
The Index measures “homes buyers scrutinised”, not “all homes for sale”.
5. What we exclude, and why
- Scotland and Northern Ireland. Our sold-price data covers England & Wales only. Run on Scottish postcodes, the method produces artefacts — whole cities showing every property the same distance below “fair value”, which is a systematic offset in the estimate, not a market signal. We publish nothing rather than publish that.
- Areas below the sample floor. Some show dramatic figures on twenty or thirty properties. They are excluded even when — especially when — they would make a better headline than the areas we do publish.
- Extreme individual gaps. Capped at ±50%, as above. These are real listings, but the extreme percentage reflects uncertainty in the estimate where comparable sales are scarce.
6. What the Index cannot tell you
- It is not a sold-price measure. We do not yet track what these homes eventually sold for. A gap to asking price is not proof a home is overpriced — only that its asking price sits above the evidence we can see. Sellers routinely and rationally list above the evidence and negotiate down.
- It is not a valuation. Fair value here is an evidence-based estimate, not a RICS-regulated valuation and not a survey. It cannot see inside a property: condition, renovation, specification and layout are invisible to it.
- It is not yet a long time series. Our report history begins in April 2026, so the rolling window currently overlaps most of the data we hold. It becomes a genuine month-on-month read as history accrues.
- Area composition varies. The areas with the widest gaps skew towards detached family homes; inner-London areas skew towards flats. Comparing two areas compares two different mixes of property.
7. How Hauscope makes money
We think you should know this before you decide what the Index is worth.
Hauscope is free for buyers. We make money from local professionals — a mortgage broker, a surveyor, a conveyancer — who pay us a subscription to be the one person we introduce buyers to in their area, if the buyer asks for an introduction. That is our revenue: partner subscriptions. We are not paid per lead, we do not sell buyer details to panels or call centres, and we do not run advertising on these pages.
What that means for the Index: no partner, advertiser or estate agent can pay to change a figure on this page, or to change the estimate on any individual property report. The Index is computed from our report history by a scheduled job under the rules in §3, with no manual step at which a number could be adjusted, and no commercial input to the calculation at all.
We also have an obvious interest worth naming: an Index showing that asking prices exceed the evidence makes our product look useful. That is exactly why the national figure is published as it falls — small — rather than framed as a scandal, why the selection bias in §4 is stated as the biggest caveat rather than a footnote, and why the full ranked table is published including every area that undercuts the story.
8. Corrections
If you think a figure here is wrong, tell us and we will check it and publish a correction on this page rather than quietly amend it. Editions are stored as published. press@hauscope.com.
The Index is free to reproduce with attribution to Hauscope and a link to the Index page.