Jakość danych o cenach transakcyjnych na rynku nieruchomości

The paper presents specification an elementary problems of data quality reported transaction prices on the real estate market. These prices are the basis of market analysis and valuation of the property, which are doing for various needs. The poor quality of the input data causes the risk of erroneous results of these analyzes and valuations. The final part of the paper contains suggestions postulated legal and organizational changes that can improve the quality of transaction prices data.