Since 2002, the Central Residence Register (ZMR) has formed the data basis for recording the population status in Austria. In addition to main residence registrations, which are decisive for determining the population figure, other residences (so-called "secondary residences") are also recorded in the Central Residence Register. Yet, – in contrast to main residence registrations – these are not compiled according to population statistics criteria, i.e. without taking into account a minimum registration period and without additional quality assurance measures.