Frequently Asked Questions

Why GET rather than a JSON request body?

These requests select precomputed observations. Query parameters describe the dataset and filters. They do not submit a property for model inference or start a calculation job. The valuation API uses a different contract because it accepts a property specification.

Are there seven market products or ten?

Ten calculation/product families are grouped into seven query datasets. Market Activity combines sales and estimated price per square metre. Rental Market combines rent, capital value and yield. Grouping reduces the number of requests while preserving per-metric dates, units and coverage.

Can I request more than one area in a request?

Not in this contract. A market series request selects one LAD and one segment. Retrieve other selections separately with controlled concurrency. Pagination retrieves more observations for the same selection; it is not a multi-area batch.

Does no date mean all history?

No. Omitting both dates selects latest. Supply a lower date for history from that point or an upper date for available history through that point. Equal lower/upper dates select one exact period.

Is June's sales count the number sold in June?

No, it is a rolling 12-month count ending in June. Read period_start and period_end. Adjacent points overlap, so adding them is not an annual total.

Why do rent and property value have different months?

Rental publications can advance before core sale-derived estimates. The grouped response preserves those distinct dates. Yield discloses both inputs and their gap; it does not make the older capital estimate newer.

Why is a local share not 20% in each price band?

Bands are based on the England/Wales transaction-price distribution, not quintiles within each LAD. Local markets can be concentrated in particular national bands.

Is estimated price per square metre the median of every local sale?

No. It uses usable linked area evidence and estimation. Not every recorded sale has usable floor area. Trading counts can have broader coverage than the estimate.

Can I use the capital estimate as a valuation of a particular address?

It is a typical segment estimate, not an individual-property valuation. Use the separate Property Valuation API for a property-specific request.

Do delivery counts measure unsold new homes or planning consents?

Neither. They estimate new-dwelling delivery/certification activity. New-Build Share of Sales measures the composition of recorded trading, not the fraction of deliveries sold.

Why are studios combined with one-bedroom flats?

The supported public segmentation is studio_1. It does not imply reliable separate studio-only coverage. Other flat groups are two bedrooms and three-plus; house groups are two, three and four-plus.

Is the gross yield what a landlord earns?

It is annualised estimated rent divided by estimated segment capital value, before costs. It is not net yield, total return or the average of individual achieved investment yields.

Why can a mortgage-to-swap spread be negative?

The inputs refer to different instruments and publication/reference conventions. A negative historical comparison is not automatically a data error and is not a direct measure of lender profit.

Are indicative swaps tradeable prices?

No. They are analytical curve-derived equivalents. Actual executable quotes can differ in timing, conventions, credit terms and bid/offer.

Is market-implied inflation a CPI forecast?

No. It is market inflation compensation inferred from gilt pricing. It is not observed CPI and includes influences beyond expected inflation.

Can I ask for a rate 24 months ahead using a future to date?

No. Observation-date filters select retained observations or snapshots. Select a scenario/forward dataset and use horizon parameters for future assumptions.

Does 200 mean every value was available?

No. A valid selection may return unavailable metrics, null values or no observations. Read per-series availability and per-observation status. A 503, by contrast, means the service/release could not safely supply the data.

Does an old observation date tell me what was known then?

No. It selects historical observations from the chosen release, which may contain revisions. Reconstructing prior information requires a retained release from that time; the API does not fabricate vintages.

Can I request arbitrary maturities, property subtypes or custom shocks?

No. Use the documented selectors and retained nodes. The API does not interpolate customer nodes or infer unsupported categories.

How do I access both data families?

Your key needs the appropriate family permissions and dataset entitlements. Valuation access does not automatically include Data Bank access. Use each family's /datasets endpoint to discover the datasets and metrics your account can request.

Why is one month missing from an otherwise available series?

An estimate under review is returned with status: withheld_pending_review and a null value. Other months and unaffected metrics remain available. Display a gap rather than substituting zero or carrying an older estimate forward. This is a data-quality status, not an HTTP failure. See Coverage and Quality.