This is something I wanted to study since some time ago: How the prices per m2 will compare among the data from the Ministry of Housing and the Association of Notaries (official) and Fotocasa, one of the best real estate pages of Spain?
The general tendency is the same although there is a deviation between the official and the web one. That is normal because Fotocasa measures properties “For Sale” on its web and the official data considers “Sold” properties. What is interesting is that the difference, in the period from 2010 to 2012, is 11,91%. That, as an average, may be the difference between starting prices and closing prices. My own statistics show a 11% deviation so quite close to the one obtained in this study.
