Prices and indices
Forecast tail
The points at the end of an index series that fall after the last settled month, projected rather than measured, flagged is_forecast with a lower and upper band.
Also called: index forecast, is_forecast, nowcast.
Definition
Forecast tail, as the data uses it
Because of registration lag, the last few months of a sold-price index are not yet measurable. Rather than stop the series early or publish a number that will move, MarketCode publishes those months as forecasts: each point carries is_forecast: true and a lo and hi band, and the series reports the last_settled_period so a reader knows where measurement ends.
The forecast is a projection from the settled series, not a prediction of policy or shocks. Treat the band as the honest width of what is known; a headline that quotes the forecast point without the band is quoting more precision than exists.
Tools
Tools that return it
House price index series
market_index_series()The published house-price INDEX for one postcode district or local authority: the level per month (base period = 100), the forecast tail flagged, and provenance saying how the index was built.
See also
Related terms
- Registration lag: The weeks to months between a sale completing and HM Land Registry registering it, which makes the most recent months of any sold-price series incomplete.
- Repeat-sales index: A price index built from pairs of sales of the same property, so it measures price change without being pulled by which properties happened to sell; the method behind MarketCode's sold-price and commercial capital indices.
FAQ
Questions about forecast tail
What does Forecast tail mean?
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The points at the end of an index series that fall after the last settled month, projected rather than measured, flagged is_forecast with a lower and upper band.
Which MarketCode tools return forecast tail?
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House price index series. Each runs as an MCP tool in Claude, ChatGPT, Codex and Cursor and as a REST endpoint with an API key, at the same price.
Is is_forecast the same thing?
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Yes. index forecast, is_forecast, nowcast are other names for what this entry defines; MarketCode uses "Forecast tail" in its tool descriptions and responses.
See it on a real address.
Thirty minutes, your property or area, every figure sourced.