The monthly business outlook survey in the building industry is part of the European system to harmonise European Commission business outlook surveys, and to which the 27 Member States of the European Union contribute.

Thus questionnaires, classifications and data processing methods have been harmonised to a large extent in the national institutes of the countries that have adopted this system.

Questions are formulated so that they can be answered quickly (most of the questions are qualitative with three response options expressed in the form "higher, lower, stable", or "more than normal, normal, less than normal").