Changes in market prices of residential premises adjusted for changes in the structure of sold premises taking place from period to period.

There are prices of residential premises located in multi-dwelling buildings, purchased by households. Indices are compiled using stratification method, that consists in dividing transactions into possibly homogeneous groups. Stratification is based on market segment (primary/secondary market), premises location and size. An elementary-level index is computed for each strata as a quotient of the average price in the current period and the average price in the base period (fourth quarter of the previous year). Indices for higher aggregation levels are calculated using a Laspeyres' formula with a weighting system based on the value of residential premises sold in the year preceding the year under survey.

Calculations take into account data on market transactions, i.e. sales on the free market (with some exclusions, e.g. sales between related parties) and sales under tender procedure. In case of lack of appropriate information in datasets from RCiWN, the breakdown into the primary and secondary market is based on the assumption that sales on the primary market concern transactions made on the free market by legal persons and the average price per 1 m2 of usable floor area is at least PLN 2,000. Transactions on the secondary market include the rest of market transactions concluded on the free market as well as sales under tender procedure.