How we prepare and compare property transaction data

The source and its limits

Our transaction records come from the National Property Information Centre (NAPIC) open transaction dataset. A recorded sale price describes one transaction. It is not an asking price, an auction reserve or a valuation of another property.

We keep a rolling selection of the published history. Area pages show the dates available in that selection. NAPIC can add or revise records; a recent sale may not appear yet. An empty search result means we did not find a record in our current data, rather than proof that no sale occurred.

Visit the NAPIC portal to inspect the source provider.

One place can have more than one recorded name

We retain the original road and scheme names alongside searchable versions. Simple normalization makes case, repeated spaces and supported abbreviations easier to search. Reviewed naming relationships can also help a familiar name lead to records filed under another label.

A similar name alone is not proof of the same location. A relationship used to help someone discover a record does not automatically combine its prices with another area's prices. District, property type and the evidence behind the match still matter.

Why an area can contain houses, shops and flats

A NAPIC scheme label can cover several property types. We show the recorded type and let you inspect each group. The default all-types view does not display a blended median.

An area median needs at least 8 priced sales of the selected type. It is withheld when the available history is capped, the district cannot be narrowed, the type is missing, or exclusions cannot be applied to the correct records. The page explains the reason.

Even within one type, size, tenure, condition and transaction date can differ. A type-specific median is a summary of those recorded sales, not an appraisal of a particular unit.

Sale price and price per square foot answer different questions

The median sale price is the middle recorded price, averaging the middle pair for an even number of sales. Median RM/sqft is calculated from individual usable price-per-area values; it is not the median price divided by the median size.

We convert supported source units to square feet and identify the area basis used. Land area and built-up area are different measurements. Missing or unsuitable area data can leave RM/sqft unavailable even when a recorded sale price exists.

What an above/below percentage means

A listing's percentage compares its auction reserve with the recorded benchmark selected by the matching rules. Those rules apply additional property-type, location and size checks. A lower reserve does not establish the property's market value, condition, eventual selling price or suitability for a buyer.

Some repeated-price groups are excluded from benchmarks under the existing evidence checks. Repetition alone is insufficient. Where exclusions or incomplete data prevent a defensible comparison, the comparison is withheld.

How a refresh becomes searchable

An import retains the source fields and prepares separate searchable names. Derived area pages are rebuilt from those records. An incomplete naming step must stop the rebuild rather than make existing areas disappear. These checks help keep the search index consistent; they cannot guarantee the original dataset contains every sale or that every source label is correct.

Use the records alongside your own budget

The upfront cash planner separates the purchase contribution from other entered costs. The affordability calculator explores a monthly budget, and the rental yield calculator tests entered rent against costs and repayments. Their inputs are estimates, not promises of financing or returns.

Found a missing or incorrect record?

Send the page URL, the name you searched and a public source that supports the correction to jj@owaoconsulting.com. Avoid sending identity documents or private account details. We can investigate a naming or extraction problem without presenting an unverified reported sale as a NAPIC record.