"For longer than 10 years, gif's working group II ""Market Analyses and Forecasts"" has been working to enhance the German property market's transparency. As German official statistics hardly publish any data on the property market, nearly all information and market data is based on the reports of several real estate consultants and property advisors. Problems occur as these market reports by the private sector usually are published without common definitions and data differs widely between the single reports. gif's working group has initiated a discussion amongst the researchers working for these real estate advisors publishing market reports. As a result, a common set of harmonised definitions has been agreed on. This will help the market to be provided with data, that actually refers to common geographical areas and that has been generated by coordinated methods. At the same time, the gif working group has taken great effort to gather the relevant market players in a group exchanging information in order to improve the data quality. These definitions are now being presented to the public and posed for discussion. "