How to handle revisions to Türkiye’s Housing Price Index
TCMB’s Housing Price Index (KFE) is a statistical time series designed to track changes in housing-market prices; it is not a valuation of an individual property. The official TCMB page provides the time series through EVDS together with metadata and a revision-policy link, and it notes that the calculation methodology has been revised. When a historical index observation is used in an investment memo, record the dataset version and retrieval date. A value seen when a report was prepared can later be revised, so reopening the series months later may produce a different observation for an earlier period.
When two versions differ, first determine whether the difference reflects a new market month, a revision to previously published data or a methodological change. Comparing exported files without release dates can create the false impression that the market changed in an old month when the published series was actually revised. Maintain a compact data dictionary containing series name or code, geography, nominal or real status, period, extraction date and unit. If annual or cumulative growth is calculated locally, retain the formula and source observations used in the calculation.
A national or regional index is not a neighbourhood price
KFE is useful for market context and time comparison, but it does not replace property-level comparables. Province and micro-location, building age, size, view, occupancy, project characteristics and floor level can cause a specific unit to behave differently from the index. It is therefore unsafe to apply the index growth rate directly to an old apartment price and call the result “fair value.” Transaction analysis should use relevant comparables and professional valuation where required, while KFE remains a macro or regional reference.
When discussing nominal and real movements, state exactly which series was used and how inflation was treated. Saying “housing prices rose” can refer to nominal lira growth while purchasing-power-adjusted movement is different. Do not mix KFE with commercial-property or rent indicators simply because all are published by TCMB; each series has its own definition, population and methodology.
Create a revision log for recurring investment reports
Do not silently overwrite last month’s historical figures. Flag observations changed by an official revision and note whether the investment conclusion changes. If an acquisition rule depends on a growth threshold, re-test the rule after the update. For auditability, retain the source export or EVDS reference, series identifier and retrieval date. This makes it possible to distinguish a genuinely new market observation from a statistical reassessment of the past—the central discipline when working with a revised housing-price series.